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 When we say changing states, we are referring to much more than the dramatic states created by LSD, isolation tanks, REM. sleep, etc. We are also including normal states of consciousness, which we can imagine as kindled ‘default settings' of our various modalities. When any one of these settings returns to one of its default settings, it will, we conjecture, tend to entrain all the other modalities to the settings they habitually take in that state.
 To accomplish this, we must suggest that each modality be connected to every other one. A sight, a smell, a sound, or a tactile feeling can all inspire fear. Fear can motivate ideation. Ideation can inspire arousal. Changes in effect can initiate alterations in introspection. Introspection alters affect. State specific settings of individual modalities could initiate settings for other modalities.
 Our main hypothesis here is that all these intermodal connections, as operating as a single system, have a single Phenomenological correlate. The phenomena of subjective awareness.
 The structures associated with that modality then broadcasts are neuromagnetic signals to the temporal lobes, which then produces signals that then recruits various structures throughout the brain. Specifically, those structures whose associated modalities' values must be changed in order to accomplish the appropriate alteration in state. In the second section, we found the possibility that states are settings for the variable aspects of cognitive and sensory modalities. We also offered the suggestion that consciousness is the Phenomenological correlate of the feedback between the management of states on the one hand, and the various cognitive and sensory modalities, on the other. If all of these conclusions were to stand up to testing, we could conclude that the content of the brain's hypothesized endogenous magnetic signals might consist of a set of values for adjusting each sensory and cognitive rheostat. We might also conclude that neuromagnetic signalling is the context in which consciousness occurs.
 The specific mechanism whereby subjectivity is generated is out of the reach of this work. Nevertheless, we can say that the fact that multiple modalities are experienced simultaneously, together with our model's implication that they are ‘reset,' all at once, with each alteration in state suggests that our postulated neuromagnetic signals may come in pairs, with the two signals running slightly out of condition with one another. In this way, neuromagnetic signals, like the two laser beams used to produce a hologram, might be able to store information in a similar way, as has already been explored by Karl Pibhram. The speed at which neuromagnetic signals continue to propagate, and together with their capacity to recruit/alter multiple modalities suggests that the underlying mechanism have been selected to make instant choices on which specific portions to recruit in order to facilitate the behaviours acted out of the State, and to do so quickly.
 In this way, the onset time for the initiation of States is kept to a minimum, and with it, the times needed to make the initial, cognitive response to stimuli. When it comes to response to threats, or sighting prey, the evolutionary advantages are obvious.
 Higher-order theories of consciousness try to explain the distinctive properties of consciousness in terms of some relation obtaining between the conscious state in question and a higher-order representation of some sort (either a higher-order experience of that state, or a higher-order thought or belief about it). The most challenging properties to explain are those involved in phenomenal consciousness-the sort of state that has a subjective dimension, which has ‘feel’, or which it is like something to undergo.
 One of the advances made in recent years has been in distinguishing between different questions concerning consciousness. Not everyone agrees on quite which distinctions need to be drawn. But all are agreeing that we should distinguish creature consciousness from mental-state consciousness. It is one thing to say of an individual or organism that it is conscious (either in general or of something in particular). It is quite another thing to say of one of the mental states of a creature that it is conscious.
 It is also agreed that within creature-consciousness itself we should distinguish between intransitive and transitive variants. To say of an organism that it is conscious, and finds of its own sorted simplicities (intransitive) is to say just that it is awake, as opposing to an ever vanquishing state of unconsciousness, only to premises the fact, that the unconscious is literally resting, not of an awakening state. There do not appear to be any deep philosophical difficulties lurking here (or at least, they are not difficulties specific to the topic of consciousness, as opposed to mentality in general). But to say of an organism that it is conscious of such-and-such (transitive) is normally to say at least that it is perceiving such-and-such, or aware of such-and-such. So we say of the mouse that it is conscious of the cat outside its hole, in explaining why it does not come out is, perhaps, to mean that it perceives the cat's presence. To provide an account of transitive creature-consciousness would thus be to attempt a theory of perception.
 There is a choice to be made concerning transitive creature-consciousness, failure to notice which may be a potential source of confusion. For we have to decide whether the perceptual state in virtue of which an organism may be said to be transitively-conscious of something must itself be a conscious one (state-conscious). If we say ‘Yes’ then we will need to know more about the mouse than merely that it perceives the cat if we are to be assured that it is conscious of the cat-we will need to establish that its percept of the cat is itself conscious. If we say ‘No’, on the other hand, then the mouse's perception of the cat will be sufficient for the mouse to count as conscious of the cat, but we may have to say that although it is conscious of the cat, the mental state in virtue of which it is so conscious is not itself a conscious one! It may be best to by-pass any danger of confusion here by avoiding the language of transitive-creature-consciousness altogether. Nothing of importance would be lost to us by doing this. We can say simply that organism O observes or perceives x. We can then assert, explicitly, that if we wish, that its percept be or is not conscious.
 Turning now to the notion of mental-state consciousness, the major distinction here is between phenomenal consciousness, on the one hand-which is a property of states that it is like something to be in, which have a distinctive ‘feel’ (Nagel, 1974)-and various functionally-definable forms of access consciousness, on the other. Most theorists believe that there are mental states-such as occurrent thoughts or judgments-which are access-conscious (in whatever is the correct functionally-definable sense), but which are not phenomenally conscious. In contrast, there is considerable dispute as to whether mental states can be phenomenally-conscious without also being conscious in the functionally-definable sense-and even more dispute about whether phenomenal consciousness can be reductively explained in functional and/or representational terms.
 It seems plain that there is nothing deeply problematic about functionally-definable notions of mental-state consciousness, from a naturalistic perspective. For mental functions and mental representations are the staple fares of naturalistic accounts of the mind. But this leaves plenty of room for dispute about the form that the correct functional account should take. Some claim that for a state to be conscious in the relevant sense is for it to be poised to have an impact on the organism's decision-making processes, perhaps also with the additional requirement that those processes should be distinctively rational ones. Others think that the relevant requirement for access-consciousness is that the state should be suitably related to higher-order representations-experiences and/or beliefs-of that very state.
 What is often thought to be naturalistically problematic, in contrast, is phenomenal consciousness.  And what is really and deeply controversial is whether phenomenal consciousness can be explained in terms of some or other functionally-definable notion. Cognitive (or representational) theories maintain that it can. Higher-order cognitive theories maintain that phenomenal consciousness can be reductively explained in terms of representations (either experiences or beliefs) which are higher-order. Such theories concern us here.
 Higher-order theories, like cognitive/representational theories in general, assume that the right level at which to seek an explanation of phenomenal consciousness is a cognitive one, providing an explanation in terms of some combination of causal role and intentional content. All such theories claim that phenomenal consciousness consists in a certain kind of intentional or representational content (analog or ‘fine-grained’ in comparison with any concepts we may possess) figuring in a certain distinctive position in the causal architecture of the mind. They must therefore maintain that these latter sorts of mental property do not already implicate or presuppose phenomenal consciousness. In fact, all cognitive accounts are united in rejecting the thesis that the very properties of mind or mentality already presuppose phenomenal consciousness, as proposed by Searle (1992, 1997) for example.
 The major divides among representational theories of phenomenal consciousness in general, is between accounts that are provided in purely first-order terms and those that implicate higher-order representations of one sort or another (see below). These higher-order theorists will allow that first-order accounts-of the sort defended by Dretske (1995) and Tye (1995), for example-can already make some progress with the problem of consciousness. According to first-order views, phenomenal consciousness consists in analog or fine-grained contents that are available to the first-order processes that guide thought and action. So a phenomenally-conscious percept of red, for example, consisting in a state, with which the parallel contentual representations are red under which are betokened in such a way as to take food into thoughts about red, or into actions that are in one way or another guide by way of redness. Now, the point to note in favour of such an account is that it can explain the natural temptation to think that phenomenal consciousness is in some sense ineffable, or indescribable. This will be because such states have fine-grained contents that can slip through the mesh of any conceptual net. We can always distinguish many more shades of red than we have concepts for, or could describe in language (other than indexically -, e.g., ‘That shade’)
 The main motivation behind higher-order theories of consciousness, in contrast, derives from the belief that all (or at least most) mental-state types admit of both conscious and non-conscious varieties. Almost everyone now accepts, for example, (post-Freud) that beliefs and desires can be activated non-consciously. (Think, here, of the way in which problems can apparently become resolved during sleep, or while one's attention is directed to other tasks. Notice, that appearance to non-conscious intentional states is now routine in cognitive science.) And then if we ask what makes the difference between a conscious and a non-conscious mental state, one natural answer is that consciously states are states we are aware of them but not as to their actualization as based upon its nature. And if awareness is thought to be a form of creature-consciousness, then this will translate into the view that conscious states are states of which the subject is aware, or states of which the subject is creature-conscious. That is to say, these are states that are the objects of some sort of higher-order representation-whether to some higher-order of perception or experience, or a higher-order of belief or thought.
 One crucial question, then, is whether perceptual states as well as beliefs admit of both conscious and non-conscious varieties. Can there be, for example, such a thing as a non-conscious visual perceptual state? Higher-order theorists are united in thinking that there can. Armstrong (1968) uses the example of absent-minded driving to make the point. Most of us at some time have had the rather unnerving experience of ‘coming to’ after having been driving on ‘automatic pilot’ while our attention was directed elsewhere-perhaps having been day-dreaming or engaged in intense conversation with a passenger. We were apparently not consciously aware of any of the route we have recently taken, nor of any of the obstacles we avoided on the way. Yet we must surely have been seeing, or we would have crashed the car. Others have used the example of blind-sight. This is a condition in which subjects have had a portion of their primary visual cortex destroyed, and apparently become blind in a region of their visual field as a result. But it has now been known for some time that if subjects are asked to guess at the properties of their ‘blind’ field (e.g., whether it contains a horizontal or vertical grating, or whether it contains an ‘X’ or an ‘O’), they prove remarkably accurate. Subjects can also reach out and grasp objects in their ‘blind’ field with something like 80% or more of normal accuracy, and can catch a ball thrown from their ‘blind’ side, all without conscious awareness.
 More recently, a powerful case for the existence of non-conscious visual experience has been generated by the two-systems theory of vision proposed and defended by Milner and Goodale (1995). They review a wide variety of kinds of neurological and neuro-psychological evidence for the substantial independence of two distinct visual systems, instantiated in the temporal and parietal lobes respectively. They conclude that the parietal lobes provide a set of specialized semi-independent modules for the on-line visual control of action; Though the temporal lobes are primarily concerned with subsequent off-line functioning, such as visual learning and object recognition. And only the experiences generated by the temporal-lobe system are phenomenally conscious, on their account.
 (Note that this is not the familiar distinction between what and where visual systems, but is rather a successor to it. For the temporal-lobe system is supposed to have access both to property information and to spatial information. Instead, it is a distinction between a combined what-where system located in the temporal lobes and a how-to or action-guiding system located in the parietal lobes.)
 To get the flavour of Milner and Goodale's hypothesis, consider just one strand from the wealth of evidence they provide. This is a neurological syndrome called visual form agnosia, which results from damage localized to both temporal lobes, leaving primary visual cortex and the parietal lobes composed. (Visual form agnosia is normally caused by carbon monoxide poisoning, for reasons that are little understood.) Such patients cannot recognize objects or shapes, and may be capable of little conscious visual experience; still, their sensorimotor abilities remain largely intact
 One particular patient  has now been examined in considerable detail. While D.F. is severely agnosia, she is not completely lacking in conscious visual experience. Her capacities to perceive colours and textures are almost completely preserved. (Why just these sub-modules in her temporal cortex should have been spared is not known.) As a result, she can sometimes guess the identity of a presented object-recognizing a banana, say, from its yellow Collor and the distinctive texture of its surface. Nevertheless, she is unable to perceive the shape of the banana (whether straight or curved, say); Nor its orientation (upright or horizontal), nor of many of her sensorimotor abilities are close too normal-she would be able to reach out and grasp the banana, orienting her hand and wrist appropriately for its position and orientation, and using a normal and appropriate finger grip. Under experimental conditions it turns out that although D.F. is at chance in identifying the orientation of a broad line or letter box, she is almost normal when posting a letter through a similarly-shaped slot oriented at random angles. In the same way, although she is at chance when trying to choose as between the rectangular Forms of very different sizes, her reaching and grasping behaviours when asked to pick up such a Form are virtually indistinguishable from those of normal controls. It is very hard to make sense of this data without supposing that the sensorimotor perceptual system is functionally and anatomically distinct from the object-recognition/conscious system.
 There is a powerful case, then, for thinking that there are non-conscious as well as conscious visual percepts. While the perceptions that ground your thoughts when you plan in relation to the perceived environment (‘I'll pick up that one’) may be conscious, and while you will continue to enjoy conscious perceptions of what you are doing while you act, the perceptual states that actually guide the details of your movements when you reach out and grab the object will not be conscious ones, if Milner and Goodale (1995) are correct
 But what implication does this have for phenomenal consciousness? Must these non-conscious percepts also be lacking in phenomenal properties? Most people think so. While it may be possible to get oneself to believe that the perceptions of the absent-minded car driver can remain phenomenally conscious (perhaps lying outside of the focus of attention, or being instantly forgotten), it is very hard to believe that either blind-sight percepts or D.F.'s sensorimotor perceptual states might be phenomenally conscious ones. For these perceptions are ones to which the subjects of those states are blind, and of which they cannot be aware. And the question, then, is what makes the relevant difference? What is it about a conscious perception that renders it phenomenal, which a blind-sight perceptual state would correspondingly lack? Higher-order theorists are united in thinking that the relevant difference consists in the presence of something higher-order in the first case that is absent in the second. The core intuition is that a phenomenally conscious state will be a state of which the subject is aware.
 What options does a first-order theorist have to resist this conclusion? One is to deny the data, it can be said that the non-conscious states in question lack the kind of fineness of grain and richness of content necessary to count as genuinely perceptual states. On this view, the contrast discussed above isn't really a difference between conscious and non-conscious perceptions, but rather between conscious perceptions, on the one hand, and non-conscious belief-like states, on the other. Another option is to accept the distinction between conscious and non-conscious perceptions, and then to explain that distinction in first-order terms. It might be said, for example, that conscious perceptions are those that are available to belief and thought, whereas non-conscious ones are those that are available to guide movement. A final option is to bite the bullet, and insist that blind-sight and sensorimotor perceptual states are indeed phenomenally conscious while not being access-conscious. On this account, blind-sight percepts are phenomenally conscious states to which the subjects of those states are blind. Higher-order theorists will argue, of course, that none of these alternatives is acceptable.
 In general, then, higher-order theories of phenomenal consciousness claim the following: A phenomenally conscious mental state is a mental state (of a certain sort-see below) which either is, or is disposed to be, the object of a higher-order representation of a certain sort. Higher-order theorists will allow, of course, that mental states can be targets of higher-order representation without being phenomenally conscious. For example, a belief can give rise to a higher-order belief without thereby being phenomenally conscious. What is distinctive of phenomenal consciousness is that the states in question should be perceptual or quasi-perceptual ones (e.g., visual images as well as visual percepts). Moreover, most cognitive/representational theorists will maintain that these states must possess a certain kind of analog (fine-grained) or non-conceptual intentional content. What makes perceptual states, mental images, bodily sensations, and emotions phenomenally conscious, on this approach, is that they are conscious states with analog or non-conceptual contents. So putting these points together, we get the view that phenomenally conscious states are those states that possess fine-grained intentional contents of which the subject is aware, being the target or potential target of some sort of higher-order representation.
 There are then two main dimensions along which higher-order theorists disagree among themselves. One relate to whether the higher-order states in question are belief-like or perception-like. That taking to the former option is higher-order thought theorists, and those taking the latter are higher-order experience or ‘inner-sense’ theorists. The other disagreement is internal to higher-order thought approaches, and concerns whether the relevant relation between the first-order state and the higher-order thought is one of availability or not. That is, the question is whether a state is conscious by virtue of being disposed to give rise to a higher-order thought, or rather by virtue of being the actual target of such a thought. These are the options that will now concern us.
 According to this view, humans not only have first-order non-conceptual and/or analog perceptions of states of their environments and bodies, they also have second-order non-conceptual and/or analog perceptions of their first-order states of perception. Humans (and perhaps other animals) not only have sense-organs that scan the environment/body to produce fine-grained representations that can then serve to ground thoughts and action-planning, but they also have inner senses, charged with scanning the outputs of the first-order senses (i.e., perceptual experiences) to produce equally fine-grained, but higher-order, representations of those outputs (i.e., to produce higher-order experiences). A version of this view was first proposed by the British Empiricist philosopher John Locke (1690). In our own time it has been defended especially by Armstrong.
 (A terminological point: this view is sometimes called a ‘higher-order experience (HOE) theory’ of phenomenal consciousness; But the term ‘inner-sense theory’ is more accurate. For as we will see in section 5, there are versions of a higher-order thought (HOT) approaches that also implicate higher-order perceptions, but without needing to appeal to any organs of inner sense.
 (Another terminological point: ‘Inner-sense theory’ should more strictly be called ‘higher-order-sense theory’, since we of course have senses that are physically ‘inner’, such as pain-perception and internal touch-perception, which are not intended to fall under its scope. For these are first-order senses on a par with vision and hearing, differing only in that their purpose is to detect properties of the body rather than of the external world. According to the sort of higher-order theory under discussion in this section, these senses, too, determine what needs have their outputs scanned to produce higher-order analog contents in order for them to become phenomenally conscious. In what follows, however, the term ‘inner sense’ will be used to mean, more strictly, ‘higher-order sense’, since this terminology is now pretty firmly established.)
 A phenomenally conscious mental state is a state with analog/non-conceptual intentional content, which is in turn the target of a higher-order analog/non-conceptual intentional state, via the operations of a faculty of ‘inner sense’.
On this account, the difference between a phenomenally conscious percept of red and the sort of non-conscious percepts of red that guide the guesses of a blind-sighter and the activity of sensorimotor system, is as follows. The former is scanned by our inner senses to produce a higher-order analog state with the content experience of red or seems red, whereas the latter states are not-they remain merely first-order states with the analog content red.  In so remaining, they lack any dimension of seeming or subjectivity. According to inner-sense theory, it is our higher-order experiential themes produced by the operations of our inner-senses which make some mental states with analog contents, but not others, available to their subjects. And these same higher-order contents constitute the subjective dimension or ‘feel’ of the former set of states, thus rendering them phenomenally conscious.
 One of the main advantages of inner-sense theory is that it can explain how it is possible for us to acquire purely recognisable concepts of experience. For if we possess higher-order perceptual contents, then it should be possible for us to learn to recognize the occurrence of our own perceptual states immediately-or ‘straight off’-grounded in those higher-order analog contents. And this should be possible without those recognizable concepts thereby having any conceptual connections with our beliefs about the nature or content of the states recognized, nor with any of our surrounding mental concepts. This is then how inner-sense theory will claim to explain the familiar philosophical thought-experiments concerning one's own experiences, which are supposed to cause such problems for physicalist/naturalistic accounts of the mind.
 For example, I can think, ‘This type of experience [as of red] might have occurred in me, or might normally occur in others, in the absence of any of its actual causes and effects.’ So on any view of intentional content that sees content as tied to normal causes (i.e., to information carried) and/or to normal effects (i.e., teleological or an inferential role), this type of experience might occur without representing red. In the same sort of way, I will be able to think, ‘This type of experience [pain] might have occurred in me, or might occur in others, in the absence of any of the usual causes and effects of pains. There could be someone in whom these experiences occur but who isn't bothered by them, and where those experiences are never caused by tissue damage or other forms of a bodily insult. And conversely, there could be someone who behaves and acts just as I do when in pain, and in response to the same physical causes, but who is never subject to this type of experience.’ If we possess purely recognitional concepts of experience, grounded in higher-order percepts of those experiences, then the thinkability of such thoughts is both readily explicable, and apparently unthreatening to a naturalistic approach to the mind.
 Inner-sense theory does face a number of difficulties, however. If inner-sense theory were true, then how is it that there is no phenomenology distinctive of inner sense, in the way that there is a phenomenology associated with each outer sense? Since each of the outer senses gives rise to a distinctive set of Phenomenological properties, you might expect that if there were such a thing as inner sense, then there would also be a phenomenology distinctive of its operation. But there doesn't appear to be any.
 This point turns on the so-called ‘transparency’ of our perceptual experience (Harman, 1990). Concentrate as hard as you like on your ‘outer’ (first-order) experiences-you will not find any further Phenomenological properties arising out of the attention you pay to them, beyond those already belonging to the contents of the experiences themselves. Paying close attention to your experience of the Collor of the red rose, for example, just produces attention to the redness-a property of the rose. But put like this, however, the objection just seems to beg the question in favour of first-order theories of phenomenal consciousness. It assumes that first-order-‘outer’-perceptions already have a phenomenology independently of their targeting by inner sense. But this is just what an inner-sense theorist will deny. And then in order to explain the absence of any kind of higher-order phenomenology, an inner-sense theorist only needs to maintain that our higher-order experiences are never themselves targeted by an inner-sense-organ that might produce third-order analog representations of them in turn.
 Another objection to inner-sense theory is as follows if there really were an organ of inner sense, then it ought to be possible for it to malfunction, just as our first-order senses sometimes do. And in that case, it ought to be possible for someone to have a first-order percept with the analog content red causing a higher-order percept with the analog content seems-orange. Someone in this situation would be disposed to judge, ‘It is rouge red, but, till, it immediately stands as non-inferential (i.e., not influenced by beliefs about the object's normal Collor or their own physical state). But at the same time they would be disposed to judge, ‘It seems orange’. Not only does this sort of thing never apparently occur, but the idea that it might do so conflicts with a powerful intuition. This is that our awareness of our own experiences is immediate, in such a way that to believe that you are undergoing an experience of a certain sort is to be undergoing an experience of that sort. But if inner-sense theory is correct, then it ought to be possible for someone to believe that they are in a state of seeming-orange when they are actually in a state of seeming-red.
 A different sort of objection to inner-sense theory is developed by Carruthers (2000). It starts from the fact that the internal monitors postulated by such theories would need to have considerable computational complexity in order to generate the requisite higher-order experiences. In order to perceive an experience, the organism would need to have mechanisms to generate a set of internal representations with an analog or non-conceptual content representing the content of that experience, in all its richness and fine-grained detail. And notice that any inner scanner would have to be a physical device (just as the visual system of itself is) which depends upon the detection of those physical events in the brain that is the output of the various sensory systems (just as the visual system is a physical device that depends upon detection of physical properties of surfaces via the reflection of light). For it is hard to see how any inner scanner could detect the presence of an experience as experience. Rather, it would have to detect the physical realizations of experiences in the brain, and construct the requisite higher-order representation of the experiences that those physical events realize, on the basis of that physical-information input. This makes is seem inevitable that the scanning device that supposedly generates higher-order experiences of our first-order visual experience would have to be almost as sophisticated and complex as the visual system itself
 Now the problem that arises here is this. Given this complexity in the operations of our organs of inner sense, there had better be some plausible story to tell about the evolutionary pressures that led to their construction. For natural selection is the only theory that can explain the existence of organized functional complexity in nature. But there would seem to be no such stories on the market. The most plausible suggestion is that inner-sense might have evolved to subserve our capacity to think about the mental states of conspecific, thus enabling us to predict their actions and manipulate their responses. (This is the so-called ‘Machiavellian hypothesis’ to explain the evolution of intelligence in the great-ape lineage. But this suggestion presupposes that the organism must already have some capacity for higher-order thought, since such thoughts in which an inner sense is supposed to subserve. And yet, some higher-order thought theories can claim all of the advantages of inner-sense theory as an explanation of phenomenal consciousness, but without the need to postulate any ‘inner scanners’. At any rate, the ‘computational complexity objection’ to inner-sense theories remains as a challenge to be answered.
 Non-dispositionalist higher-order thought (HOT) theory is a proposal about the nature of state-consciousness in general, of which phenomenal consciousness is but one species. Its main proponent has been Rosenthal. The proposal is this: a conscious mental state M, of mine, is a state that is actually causing an activated belief (generally a non-conscious one) that I have M, and causing it non-inferentially. (The qualification concerning non-inferential causation is included to avoid one having to say that my non-conscious motives become conscious when I learn of them under psychoanalysis, or that my jealousy is conscious when I learn of it by interpreting my own behaviour.) An account of phenomenal consciousness can then be generated by stipulating that the mental state M should have an analog content in order to count as an experience, and that when M is an experience (or a mental image, bodily sensation, or emotion), it will be phenomenally conscious when (and only when) suitably targeted.
 A phenomenally conscious mental state is a state with analog/non-conceptual intentional content, which is the object of a higher-order thought, and which causes that thought non-inferentially.
 This account avoids some of the difficulties inherent in inner-sense theory, while retaining the latter's ability to explain the distinction between conscious and non-conscious perceptions. (Conscious perceptions will be analog states that are targeted by a higher-order thought, whereas perceptions such as those involved in blind-sight will be non-conscious by virtue of not being so targeted.) In particular, it is easy to see a function for higher-order thoughts, in general, and to tell a story about their likely evolution. A capacity to entertain higher-order thoughts about experiences would enable a creature to negotiate the is and seems distinction, perhaps learning not to trust its own experiences in certain circumstances, and to induce appearances in others, by deceit. And a capacity to entertain higher-order thoughts about thoughts (beliefs and desires) would enable a creature to reflect on, and to alter, its own beliefs and patterns of reasoning, as well as to predict and manipulate the thoughts and behaviours of others. Indeed, it can plausibly be claimed that it is our capacity to target higher-order thoughts on our own mental state in which underlies our status as rational agents. One well-known objection to this sort of higher-order thought theory is due to Dretske (1993). We are asked to imagine a case in which we carefully examine two line-drawings, say (or in Dretske's example, two patterns of differently-sized spots). These drawings are similar in almost all respects, but differ in just one aspect-in Dretske's example, one of the pictures contains a black spot that the other lacks. It is surely plausible that, in the course of examining these two pictures, one will have enjoyed a conscious visual experience of the respect in which they differ -, e.g., of the offending spot. But, as is familiar, one can be in this position while not knowing that the two pictures are different, or in what way they are different. In which case, since one can have a conscious experience (e.g., of the spot) without being aware that one is having it, consciousness cannot require higher-order awareness.
 Replies to this objection have been made by Seager (1994) and by Byrne (1997). They point out that it is one thing to have a conscious experience of the aspect that differentiates the two pictures, and quite another to experience consciously that the two pictures are differentiated by that aspect. That is, seeing the extra spot in one picture needn't mean seeing that this is the difference between the two pictures. So while scanning the two pictures one will enjoy conscious experience of the extra spot. A higher-order thought theorist will say that this means undergoing a percept with the content spot here which forms the target of a higher-order belief that one is undergoing a perception with that content. But this can perfectly well be true without undergoing a percept with the content spot here in this picture but absent here in that one. And it can also be true without forming any higher-order belief to the effect that one is undergoing a perception with the content spot here when looking at a given picture but not when looking at the other. In which case the purported counter-example isn't really a counter-example.
 A different sort of problem with the Non-dispositionalist version of higher-order thought theory relates to the huge number of beliefs that would have to be caused by any given phenomenally conscious experience. (This is the analogue of the ‘computational complexity’ objection to inner-sense theory,  Consider just how rich and detailed a conscious experience can be. It would seem that there can be an immense amount of which we can be consciously aware at any-one time. Imagine looking down on a city from a window high up in a tower-Form, for example. In such a case you can have phenomenally conscious percepts of a complex distribution of trees, roads, and buildings, colours on the ground and in the sky above, moving cars and pedestrians, . . . and so on. And you can-it seems-be conscious of all of this simultaneously. According to Non-dispositionalist higher-order thought theory, then, you would need to have a distinct activated higher-order belief for each distinct aspect of your experience is that, of just a few such beliefs with immensely complex contents. By contrast, the objection is the same, for which it seems implausible that all of this higher-order activity should be taking place, even if non-consciously, in every time someone is the subject of a complex conscious experience. For what would be the point? And think of the amount of cognitive space that these beliefs would take up,
 This objection to Non-dispositionalist forms of higher-order thought theory is considered at some length in Carruthers (2000), where a variety of possible replies are discussed and evaluated. Perhaps the most plausible and challenging such replies would be to deny the main premise lying behind the objection, concerning the rich and integrated nature of phenomenally conscious experience. Rather, the theory could align itself with Dennett's (1991) conception of consciousness as highly fragmented, with multiple streams of perceptual content being processed in parallel in different regions of the brain, and with no stage at which all of these contents are routinely integrated into a phenomenally conscious perceptual manifold. Rather, contents become conscious on a piecemeal basis, as a result of internal or external probing that gives rise to a higher-order belief about the content in question. (Dennett himself sees this process as essentially linguistic, with both probes and higher-order thoughts being formulated in natural language. This variant of the view, although important in its own right, is not relevant to our present concerns.) This serves to convey to us the mere illusion of riches, because wherever we direct our attention, there we find a conscious perceptual content. It is doubtful whether this sort of ‘fragmental’ account can really explain the phenomenology of our experience, however. For it still faces the objection that the objects of attention can be immensely rich and varied at any given moment, hence requiring there to be an equally rich and varied repertoire of higher-order thoughts tokened at the same time. Think of immersing yourself in the colours and textures of a Van Gogh painting, for example, or the scene as your look out at your garden-it would seem that one can be phenomenally conscious of a highly complex set of properties, which one could not even begin to describe or conceptualize in any detail. However, since the issues here are large and controversial, it cannot yet be concluded that Non-dispositionalist forms of higher-order thought theory have been decisively refuted.
 According to all forms of dispositionalist higher-order thought theory, the conscious status of an experience consists in its availability to higher-order thought (Dennett, 1978). As with the Non-dispositionalist version of the theory, in its simplest form we have here a quite general proposal concerning the conscious status of any type of occurrent mental state, which becomes an account of phenomenal consciousness when the states in question are experiences (or images, emotions, etc.) with analog content. The proposal is this: a conscious mental event M, of mine, is one that is disposed to cause an activated belief (generally a non-conscious one) that I have M, and to cause it non-inferentially.
A phenomenally conscious mental state is a state with analog/non-conceptual intentional content, which is held in a special-purpose short-term memory store in such a way as to be available to cause (non-inferentially) higher-order thoughts about any of the contents of that store.
 In contrast with the Non-dispositionalist form of theory, the higher-order thoughts that render a percept conscious are not necessarily actual, but potential, on this account. So the objection now disappears, that an unbelievable amount of cognitive space would have to be taken up with every conscious experience. (There need not actually be any higher-order thought occurring, in order for a given perceptual state to count as phenomenally conscious, on this view.) So we can retain our belief in the rich and integrated nature of phenomenally conscious experience-we just have to suppose that all of the contents in question are simultaneously available to higher-order thought. Nor will there be any problem in explaining why our faculty of higher-order thought should have evolved, nor why it should have access to perceptual contents in the first place-this can be the standard sort of story in terms of Machiavellian intelligence.
 It might be wondered how their mere availability to higher-order thoughts could confer on our perceptual states the positive properties distinctive of phenomenal consciousness-that is, of states having a subjective dimension, or a distinctive subjective feel. The answer may lie in the theory of content. Suppose that one agrees with Millikan (1984) that the representational content of a state depends, in part, upon the powers of the systems that consume that state. That is, suppose one thinks that what a state represents will depend, in part, on the kinds of inferences that the cognitive system is prepared to make in the presence of that state, or on the kinds of behavioural control that it can exert. In which case the presence of first-order perceptual representations to a consumer-system that can deploy a ‘theory of mind’, and which is capable of recognitizable applications of theoretically-embedded concepts of experience, may be sufficient to render those representations at the same time as higher-order ones. This would be what confers on our phenomenally conscious experiences the dimension of subjectivity. Each experience would at the same time (while also representing some state of the world, or of our own bodies) be a representation that we are undergoing just such an experience, by virtue of the powers of the ‘theory of mind’ consumer-system. Each percept of green, for example, would at one and the same time be an analog representation of green and an analog representation of seems green or experience of green. In fact, the attachment of a ‘theory of mind’ faculty to our perceptual systems may completely transform the contents of the latter's outputs.
 This account might seem to achieve all of the benefits of inner-sense theory, but without the associated costs. (Some potential drawbacks will be noted in a moment.) In particular, we can endorse the claim that phenomenal consciousness consists in a set of higher-order perceptions. This enables us to explain, not only the difference between conscious and non-conscious perception, but also how analog states come to acquire a subjective dimension or ‘feel’. And we can also explain how it can be possible for us to acquire some purely recognitizable concepts of experience (thus explaining the standard philosophical thought-experiments). But we don't have to appeal to the existence of any ‘inner scanners’ or organs of inner sense (together with their associated problems) in order to do this. Moreover, it should also be obvious why there can be no question of our higher-order contents getting out of line with their first-order counterparts, in such a way that one might be disposed to make recognitizable judgments of red and seems orange at the same time. This is because the content of the higher-order experience is parasitic on the content of the first-order one, being formed from it by virtue of the latter's availability to a ‘theory of mind’ system.
 On the downside, for which the account is not neutral on questions of semantic theory. On the contrary, it requires us to reject any form of pure input-semantics, in favour of some sort of consumer-semantics. We cannot then accept that intentional content reduces to informational content, nor that it can be explicated purely in terms of causal covariance relations to the environment. So anyone who finds such views attractive will think that the account is a hard one to swallow.
 What will no doubt be seen by most people as the biggest difficulty with dispositionalist higher-order thought theory, however, is that it may have to deny phenomenal consciousness to most species of non-human animals. This objection will be discussed, among others, in the section following, since it can arguably also be raised against any form of higher-order theory.
 There has been the whole host of objections raised against higher-order theories of phenomenal consciousness. Unfortunately, many of these objections, although perhaps intended as objections to higher-order theories as such, are often framed in terms of one or another particular version of such a theory. One general moral to be taken away from the present discussion should then be this: the different versions of a higher-order theory of phenomenal consciousness need to be kept distinct from one another, and critics should take care to state which version of the approach is under attack, or to frame objections that turn merely on the higher-order character of all of these approaches.
 One generic objection is that higher-order theory, when combined with plausible empirical claims about the representational powers of non-human animals, will conflict with our commonsense intuition that such animals enjoy phenomenally conscious experience. This objection can be pressed most forcefully against higher-order thought theories, of either variety; However it is also faced by inner-sense theory (depending on what account can be offered of the evolutionary function of organs of inner sense). Since there is considerable dispute as to whether even chimpanzees have the kind of sophisticated ‘theory of mind’ which would enable them to entertain thoughts about experiential states as such (Byrne and Whiten, 1988, 1998; Povinelli, 2000), it seems most implausible that many other species of a mammal (let alone reptiles, birds and fish) would qualify as phenomenally conscious, on these accounts. Yet the intuition that such creatures enjoy phenomenally conscious experiences is a powerful and deep-seated one, for many people.
 The grounds for this commonsense intuition can be challenged, however. (How, after all, are we supposed to know whether it is like something to be a bat?) And that intuition can perhaps be explained away as a mere by-product of imaginative identification with the animal. (Since our images of their experiences are phenomenally conscious, that the experience’s imageable is similarly conscious. But there is no doubt that one crux of resistance to higher-order theories will lie here, for many people.
 Another generic objection is that higher-order approaches cannot really explain the distinctive properties of phenomenal consciousness. Whereas the argument from animals is that higher-order representations aren't necessary for phenomenal consciousness, the argument here is that such representations aren't sufficient. It is claimed, for example, that we can easily conceive of creatures who enjoy the postulated kinds of higher-order representation, related in the right sort of way to their first-order perceptual states, but where those creatures are wholly lacking in phenomenal consciousness.
 In response to this objection, higher-order theorists will join forces with first-order theorists and others in claiming that these objectors pitch the standards for explaining phenomenal consciousness too high. We will insist that a reductive explanation of something-and of phenomenal consciousness in particular-don’t have to be such that we cannot conceive of the explanandum (that which is being explained) in the absence of the explanans (that which does the explaining). Rather, we just need to have good reason to think that the explained properties are constituted by the explaining ones, in such a way that nothing else needed to be added to the world once the explaining properties were present, in order for the world to contain the target phenomenon. But this is disputed territory. And it is on this ground that the battle for phenomenal consciousness may ultimately be won or lost
 While orthodox medical research adheres to a linear, deterministic physical model, alternative therapist typically theorize upon that which is indeterminately nonphysical and nonlinear relationships are significant to outcome and patient satisfaction. The concept of nonlocal reality as nuocontinuum helps resolve the differences in therapeutic approach, and lets us frame a worldview that recognizes the great value of both reductive science and holistic integration. It helps distinguish the levels of description appropriate to the discussion of each, and helps in examining the relationships among consciousness, nonlocal reality, and healing.
 Most recently addressed is to some informal discussion for which the problems of evaluating alternative therapies, but Dossey highlighted the stark philosophic division between orthodox and alternative health care models. While orthodox medical research adheres to a linear, deterministic physical model, alternative therapist typically postulates that indeterminate nonphysical and nonlinear relationships are significant to outcome and patient satisfaction. As Dossey summarizes that position, "Everything that counts cannot be counted."
 The problems, of course, go beyond the research issues. The respective models bring different attitudes and approaches to the therapeutic encounter. Further, their different philosophic languages limit discussions among practitioners. Rapproachment becomes all the more unlikely when each camp considers the other, "wrong." It is believed to be helpful if we were to visualize the conflict as deriving from different frames of reference. Our collective task then becomes the finding of a common frame of reference a "cosmos in common," to echo Heraclitus sufficiently broad and deep to encompass both linear and nonlinear, local and nonlocal therapeutic points of view.
 If we are to remain true to science, we must integrate the data that science provides us, and be willing to follow where the process leads. It is increasingly apparent that physics requires us to acknowledge meta considerations, that is, considerations that lie above and beyond physics. Those of us biomedical practitioners who base our work on physics cannot disparage as "merely metaphysics" a meta physics to which physics itself points.
 As a point of departure, I would like to "frame" in general outlines a worldview that recognizes the great value of both reductive science and holistic integration, and which helps distinguish the levels of description appropriate to the discussion of each. In doing so, I will suggest a new and unweighted ecumenical term for discussing the relationships among consciousness, nonlocal reality, and healing.
 The cosmos is the general descriptive term for all-that-is, which we have come to understand as an organic system of interrelated nested subsystems. Yet its most ancient representation in art is a circle. In our ordinary positivist view of things conditioned by science, the term denotes only the material nature of the universe, governed by the laws of physics. In the ordinary local cause-effect world, time-distance relationships apply, and the speed limit is that of light. Actions are mediated through a field, and forces are dissipated over distance.
 However, Bell's Theorem in quantum physics  establishes that "underneath" ordinary space-time phenomena there lies a deep nonlocal reality in which none of these limitations applies. To diagram cosmos one must find an appropriate way to divide the one circle. We might add an inner concentric circle, but the cosmos, as the term is currently used, would identify only the outer material "shell" of our experience of physical things. We have no agreed technical term for that which is "more" than matter, or beyond or outside it, or inside it. Syche has scientific validity as a psychological term. It denotes an inner personal dimension representing that aspect of experience that is normally unconscious to us, but which nevertheless influences individual human behaviour. However, in ordinary usage, the term psyche (soul, spirits) has no meaning apart from the individual human personality. To speak of the soul or spirit of matter (one hardly dare do so publicly) does not compute. Yet, now physics says there is a nonlocal more to the matter-work of the cosmos, and that domain is somehow related to the existence of consciousness.
 But there needs to be still another inner concentric circle, or at least a centre-point. Cosmologists are beginning to speak more openly about a purposeful cosmos. For example, Hawking has asked, "Why does the universe go to the integral of the bother of existing?" If science is to ask "Why" as Hawking does, it must seek the "meaning" of matter. But Meaning ordinarily has no significance in science. To speak of meaning is to speak of significance or order beyond superficial appearances. To speak of meaning in relation to the cosmos is to speak of metaphysics, the realm of religion and philosophy.
 Yet, such meaning is implicit in the anthropic principle of physics,  and in the strange attractors by which order emerges from chaotic chemical and nonlinear mathematical systems. Though such meaning is an idea new to modern science, religion and philosophy have variously described it as logos, to Way, and Word. In that of residing in "lure" of an orienting change, as mentioned by Whitehead, and in the function of the radial energy of which Teilhard spoke.
 Now, on scientific grounds alone, we must devise a "cosmorama" of at least three compartments, if it is to encompass the phenomena of the universe. Resolving and explaining these relationships may be quite complex; or it may be surprisingly simple. In any case, there are a number of questions to be answered, and a number of problems in physics and psychology that invite us to frame a unification theory.
 One principal problems in quantum physics is the question of observer effect. What is the role of consciousness in resolving the uncertainties of actions at the quantum level? Before an observation, the question of whether a quantum event has occurred can be resolved only by calculating a probability. The unconscious reality of the event is that it is a mix of the probabilities that it has happened and that it has not. That "wave function" of probabilities is said to "collapse" only at the point of observation, that is, only in the interaction of unconsciousness with consciousness.
 Schrödinger  illustrated the problem by describing a thought experiment involving a cat in a sealed box: If the quantum event happened, the cat would be poisoned; if not, when the box was opened, the cat would be found alive. Until then, we could know the result only as a calculation of probabilities. Under the condition’s Schrödinger described, we may think of the cat's condition only mathematically: the cat is both dead and alive, with equal probability. Only by the interaction of event with observer is the "wave function collapsed."
 If a tree falls in the forest when there is no one present to hear it, has there been a sound? That question can be resolved by adjusting the definition of sound. In the question of the quantum "event in the box" we are dealing with something much more fundamental. Can creation occur without an observer? Without consciousness? Or without at least the prospect of consciousness emerging from the act of creation? That may be the most basic question that begs resolving.
 Another of our unification problems is the virtual particle phenomenon. Some particles appear unpredictably, exist for extremely short periods of time, then disappear. Why does a particle appear in the force field suddenly, without apparent cause? What distinguishes stable particles from the temporary ones? Something in the force field? Something related to the act of observation?
 Another major concern of physics is the unification of the elemental physical forces. Study of the "several" forces has progressively merged them. Electricity and magnetism came to be understood as one force, not two. More recently, effects associated with the weak nuclear force were reconciled with electromagnetism, so that now we recognize one electroweak force. Further, there have been mathematical demonstrations that unify the electroweak and the strong nuclear force.
 If it could be demonstrated that the "electronuclear" force and the force of gravity are one super force (as has been widely expected), energy effects at the largest and the smallest scales of the universe would be explained. That unification process has led to a theory of a multidimensional universe, in which there are at least seven "extra" dimensions that account for the forces and the conservation laws (symmetries) of physics. They are not extra dimensions of space-time, for which one could devise bizarre travel itineraries, but abstract mathematical dimensions that in some sense constitute the nonlocal (non-space time) reality within which cosmos resides.
 However, the search for a unified theory has led to an apparent impasse, for theories of unification seem also to require a continuing proliferation of particles. A new messenger particle (or class of particles) called the Higgs boson, seems to be needed to explain how particles acquire mass, and to avoid having infinity terms (the result of a division by zero) crop up in the formulas that unify the forces. Leon Lederman, experimental physicist and Nobelist, calls it "The God Particle." He writes, "The Higgs field, the standard model, and our picture of how God made the universe depend on finding the Higgs boson."
 Still, major questions remain. To some others, particle physics has seemed to reach its limit, theoretically as well as experimentally. Oxford physicist Roger Penrose has written: If there is to be a final theory, it could only be a scheme of a very different nature. Rather than being a physical theory in the ordinary sense, it would have to remain a principle, as a mathematical principle of whose implementation might have itself involve nonmechanical subtlety.
 Perhaps the time has come for us to accept that cosmos has "infinity terms" after all.
 Psychology is conventionally defined as the study of behaviour, but for our purposes, it must be returned to the meaning implied in the roots of the word: the study of soul and spirit. Of course, the most obvious phenomenon of psychology is the emergence of consciousness. In the light of the anthropic principle of physics, we now must ask, as a distinctively psychological question, what purpose for the cosmos does consciousness serve?
 Another question: Jung has presented the evidence for an archetypal collective unconscious that, on the basis of current understandings, must certainly be inherited as the base-content of human nature. Archetypal genetics has yet to be defined. Symbol processing certainly does have its "local" physical aspect, in the function of the brain and the whole-body physiology that supports it. Nonetheless, that there is a nonlocal reality undergirding psyche is readily evident.
 The reality of the dream experience is nonlocal, unconfined by rules of time and space and normal effect. Further, it is nonlocal in that the reality extends beyond the individual, consistently following patterns evident throughout the recorded history of dream and myth. The psyche functions as though the brain, or at least its mechanisms of consciousness, is "observer" for the dream "event in the box" of an unconscious nonlocal collective reality. The archetypal unconscious suggests that there be a psychological substrate from which consciousness and its content have emerged.
 In the emergence of consciousness primally, and in the extension of consciousness in modern people through the dreaming process, the collective unconscious (self) seems to serve a nonlocal integrating function, yielding images that the conscious (ego) must differentiate from its "local" observations of the external space-time world. Thus, is consciousness extended.
 In that process, however, the ego must self-reflectively also "keep in mind" that our perception of the external physical world is not the reality of the physical world, but an interpretation of it; Nor is the external phenomenal world the only reality. To keep our interpretations of the physical world "honest," we must subject observation to tests of consistency and reason, but the calculus of consciousness is the calculus of whole process, both differential and integral. Consciousness cannot be extended, but is diminished, when it denies the reality of the unconscious.
 Jung has also pointed to certain meaningful associations between events in psyche and events in the physical world, but which are not related causally. He called such an association a synchronicity, which he defines as "an accusal connecting principle." These are simultaneous or closely associated conversions that not have connected physically, in any ordinary cause-effect way. However, they are connected meaningfully, that is, psychically. They may have very powerful impact on a person's psychic state and on the subsequent unfolding of personality. Jung studied them with Wolfgang Pauli, a quantum physicists in whose life such phenomena were overly frequent.
 A synchronicity seems to suggest that a nonlocal psychological reality either communicate with or is identical to the nonlocal reality known in physics. Since it is inconceivable to have two nonlocal realities coexisting separately from one, another, we can confidently assert that there is indeed, only one nonlocal reality.
 Another set of phenomena inviting consideration is that which includes group hysteria and mob action. A classic example is that of a high school band on a bus trip, on which all members get "food poisoning" simultaneously before a big game. After exhaustive epidemiological work, no evidence of infection or toxins is found, and the "cause" is attributed to significant amounts where stress and the power of suggestion lay. The mechanisms are entirely unconscious to the band members; it is as though their psyches have "communicated" in a way that makes them act together. Similarly, in mob action, though the members may be conscious of the anger that moves them, generally the event seems to be loaded with an unconscious dynamic within the group that prepares the way for the event itself.
 Physicist Paul Davy has written that one of the basic problems is constructing an adequate definition of the dimensionality. The ordinary dictionary definition describes a dimension in terms of magnitude or direction (height, depth, width), and we ordinarily think of the dimensions as perpendicular to each other. But that works only for the familiar spatial dimensions and the actions of ordinary objects. Imagine compressing all three-dimensional space toward a single point; As it comes close to a point, the concept of being perpendicular loses all meaning. Another problem is that it does not really make sense to think of time (which is a dimension, too) as perpendicular to anything.
 A dimension is one of the domains of action permitted to or on an object. By domain I mean something like a field of influence or action. Verticality is not a thing that acts on an object, but is rather than which permits and influences a movement in space, and which influences our description of the movement. For example, verticality is one particular aspect of abstract reality that determines the behaviour of an object. But the abstract is real! Take verticality away from three-dimensional space, and an object is permitted to move only in a way that we can analyse as a mix of horizontal and forward-backward motions. Take the horizontal away, and the object may move only along a straight line (one-dimensional space).  "String" theories, which approach a "Grand Unification" of all of the physical forces, posit dimensions beyond the four of the space-time. There is no theoretical limit to the number of dimensions, for external to space-time there is no concept of "container" or limit.
 Since all of the non-space time dimensions, by definition, are not extended in space or time, we must conceive of them as represented by points. Since they act together of o space-time, they must "intersect" or somehow communicate with the primal space-time point. For that reason (and because in the absence of space-time no point can be offset from another), we must imagine the dimensions as many points superimposed into one. Let's call it the SuperPaint. We may in fact imagine as many superimposed points (dimensions) as past and future experiments might require to explain the phenomena of creation.
 The initial conditions of our space-time universe are defined in that one SuperPaint; the Big Bang represents the explosive expansion of four of those dimensions, space-time. The creation-energy (super force) responsible for that expansion is concentrated in and at the multidimensional SuperPaint. Yet we must also think of other changes at the SuperPaint, for as energy levels dissipate immediately after the Big Bang, the super force quickly "evolves" into the four physical forces conventionally known.
 We have said that only the space-time dimensions are expanding, because the force dimensions ("contained" in the SuperPaint) are not spatial. By definition, we may not imagine non-space time points as extended in space. However, all points in expanding space-time must still "communicate" with the force dimensions (and the symmetry dimensions, but we are neglecting them for the moment). All points in space-time must intersect the force dimensions.
 It is as if the force dimensions too have been expanded to the size of space-time, for they are acting on each particle of energy/matter in the universe. One might imagine that one point has been stretched as a featureless elastic sheet, a continuum in which the point is everywhere the same.
 However, quantum theory deals with these forces as discrete waves/particles. For example, the force of gravity is communicated by gravitons; The strong nuclear force by gluons is the electromagnetic force by photons. If we conceive the stretched points of the dimensions as "sheets," the sheets must have waves in them. These "stretched sheets" which constitute the field in which energy interacts with particles to sustain (and indeed, to continue the creation of) the universe. As I have expressed it in a poem, it is the field "where the forces play pinball / with gravitons and gluons / and modulate / the all."
 Let us imagine again that space-time (four dimensions) is compressed toward a point. It is futile to ask what is outside that small pellet of space-time, for the concept of "outside ness" has no meaning but within space-time. As the pellet becomes smaller still, it shrinks toward nothingness, for a point is an abstract concept of zero dimensions, not extended in space or time, and thus it cannot "contain" anything. At that point, nothing exists except the thinker who is trying to imagine nothingness.
If we could model thought as only an epiphenomenon of matter, reached at a certain degree of complexity, it has no fundamental reality of its own. In that case, our thought experiment to shrink the cosmos reaches a point at which thought is extinguished, and the experiment must stop, if it is to follow the "rules" that it is modelling. However, by accepting that thought might have a reality of its own, and by considering the problem from a whole-system perspective, we were able to continue the thought experiment to the point at which only the thought remains. The epiphenomenon idea is not an adequate model of reality, since we can indeed continue the experiment under the conditions outlined.
 This "negative proof" is indirect, serving only to eliminate the epiphenomenon model. It does not prove that there is an independent and fundamental reality beyond space-time and matter; the experiments supporting Bell's Theorem do that. This line of thinking, however, does lead us to suggest that thought be a primary aspect of reality. It seems that the cosmos itself is saying with Descartes, "I think, therefore I am."
 Because of this inescapable "relativistic" connection between cosmos and thought, I cannot imagine creation ex nihilo (from nothing), for the concept of nothing always collides with the existence of the one who is the thinker. Nothing has any meaning apart from something. The dimension of thinking is required to imagine a zero-dimensional space-time.
 The epiphenomenon model posits that nothing is defined as the absence of matter. If that is so, thought is nothing; However, if it were nothing, I could not be thinking that thought, so thought must be of something. There can be no nothingness, for even if all that exists is reduced to nothingness, a dimension of reality remains. Reality requires at least one dimension in addition to space-time and that reality seems inseparable from the dimension of thought.
 What is missing from our existing scheme of dimensions is a description of that dimension that we could not eliminate by playing the videotape of creation in reverse: that reality at the SuperPaint from which the dimension of thought cannot be separated. That leads to a rather extravagant and intuitive proposal, following Anaxagoras: Thought is the missing particle, the missing dimension.
 Quantum physics already acknowledges the importance of consciousness as "observer." Consciousness is the substrate of thought. Thought is consciousness dimensionally extended, whether in time or some other dimension. Thought is process. Any unification of the laws of physics must necessarily take into account the thought/consciousness dimension, and thus must unify physics with psyche as well.
 In his book. The self-aware Universe, Admit Goswami uses the term consciousness to mean transcendental consciousness, which forms (or is) the nonlocal reality. Other physicists seem to define the term of cautiously, and one often wonders whether a given text about observer effect is referring to ordinary individual awareness, or to some more general property of psyche.
 It is useful to preserve the important distinction between consciousness and unconsciousness. Psychologically, ordinary human consciousness is the realm of ego and the cognitive functions called mind.  Neurologically it refers to a patient's observed state of awareness. The clinical unconscious is the realm of psyche, with both personal and collective aspects. Perhaps a better language will come along in time. Until then, let me suggest an interim language for discussing, and perhaps a framework for someday testing, the relationship between matter and psyche. Its proposal is that there is a unit of psyche, which I designate the neon, from the Greek word nous, for mind. Nuons represent the dimensions of thought that exist in (at, as) the SuperPaint defining the initial conditions of the Big Bang. As the domain of the force dimensions, those Nuons must be imagined to expand as a field or continuum (the nuocontinuum) as the space-time continuum expands, a "stretched sheet" with "waves" which are also Nuons. The Nuons of the SuperPaint are extended in space-time in a way conceptually analogous to the action of the forces.
 Yet Nuons must also be construed as the domain of the symmetries, such as the principle of conservation of energy, which are nonlocal. That is, they are everywhere in effect, without being constrained by the speed-limit of light. The nuocontinuum thus represents a multidimensional bridge between forces, symmetries, and space-time. Nuons collectively contain all potentialities, but the collective (nuocontinuum) is the unit, itself the symmetry that unifies the forces and symmetries. The Nuons is the "infinity particle" which solves the formulas.
 Does the nuocontinuum represent a fractal (fractional dimensions) such as those that give the mathematical order to the "chaos" images? Does it provide the prime tone of which the symmetries and the forces are harmonics? Whether construed mathematically or poetically, the nuocontinuum contains the information necessary to create a universe, but a universe that is organically creating itself.
 Human awareness, which occurs at a level of extraordinary complexity in the organization of space-time particles, would involve, not a "creation" of consciousness as an epiphenomenon, but a sensing of a quality that is already there, as the reality dimension of the cosmos. The observer effect at the quantum level (and the health of Schr”dinger's cat) is then to be understood as an interaction, not with a particle of concrete matter, but with the reality substrate from which matter arises.
 If we construe the whole nuocontinuum (rather than the experimenter) to be the "observer" of the quantum event in the box, we avoid much of the confusion and exasperation that Schroedinger's thought experiment evokes. Hawking wrote, "When I hear of Schroedinger's cat, and I reach for my gun." Even Einstein was repelled by quantum uncertainty. DeBroglie especially held out for an interpretation of quantum physics which supported concreteness. We rebel against the idea of a universe based on uncertainty, and we seek to assure ourselves that what we experience is a concrete reality.
 However, if the nuocontinuum is the observer that resolves the quantum uncertainty, our own individual sense of uncertainty is also resolved. The collapse of the particle wave function (the coming into being of the particle at a particular point in space-time) would be a function of the nuocontinuum acting as a whole, rather than as a local observer. The nuocontinuum is the observer who actualized creation the cosmic event in the box prior to the development of human consciousness. It is that cosmic observer who unifies the quantum effects of the electronuclear forces and the cosmic effects of gravity.
 The Nuocontinuum, then, designates an unlimited, infinite connecting principle that binds all that is. Because it accounts for the material characteristics of the cosmos, it is "Creator." Because it presents itself through the agency of human consciousness, it may be sensed as Person and named Holy Spirit or Great Mystery. It is the source of that compelling "passion" of which Teilhard spoke, "to become one with the world that envelops us." Thus, though well beyond the scope of this article, the concept has implications for depth psychology and for theology. It has potential to help humans globally recapture a sense of meaning to human life, and to understand the experiences of those whose terminologies differ. Unless we do so, or at least critical masses of us do, we remain at great risk for destroying ourselves.
 But its implications for the healing arts are also profound, for it makes us look at familiar concepts in quite a different light. In its affirmation of meaningful order in the cosmos as a whole, the nuocontinuum concept gives further definition and import to homeostasis as a healing, balancing principle that has more than physiological significance. When we invoke the term "placebo effect" we (usually unwittingly) are invoking a principle of the connectedness between an intervention and an effect, which now can be named and conceptualized. "Spontaneous remissions" of disease would be seen as something less than miracles but clearly more than merely chemical. After all, if physics can reach a limit to its powers of description, so too must be psychoneuroimmunology.
 Practitioners, have become aware of the connectedness principle, we will become more aware that our own attitudes and approaches are significant to treatment outcomes and patient satisfaction. We will then realize that even though an experiment may be "doubly-blind" to some experimenters and to some persons being tested, there may be other influences outside the cause-effect "loop" and connections of which other persons may be conscious. Further, we will better understand that there are different levels of connectivity at work in every action, which require different levels of description to explain. And we might become more sensitive to patient's hopes and expectations that so are often stated in religious terms.
 At this point in our harvest of knowledge, this synthesis is quite intuitive and speculative. However, even highly abstract drawings are often helpful in organizing thought. I hope that through some such synthesis as this, couched in whatever language, we will be given that courage to which Dossey eludes, to enter the "doorway through which we may encounter a radically new understanding of the physical world and our place in it." And, ones hope, assure the continued development of our abilities, together, to offer help to all in need of healing.
 We collectively glorify our ability to think as the distinguishing characteristic of humanity; we personally and mistakenly glorify our thoughts as the distinguishing pattern of whom we are. From the inner voice of thought-as-words to the wordless images within our minds, thoughts create and limit our personal world. Through thinking we abstract and define reality, reason about it, react to it, recall past events and plan for the future. Yet thinking remains both woefully underdeveloped in most of us, as well as grossly overvalued. We can best gain some perspective on thinking in terms of energies.
We are hanging in language. We are suspended in language in such a way that we cannot say what is up and what is down, Niels Bohr lamented in the 1920s when confronted with the paradoxes, absurdities, and seeming impossibilities encountered in the then newly discovered quantum domain. The problem, he insisted, was not the quantum wonderland itself, but our language, our ways of thinking and talking about it. His colleague, Werner Heisenberg, went a step further and proclaimed that events in the quantum wonderland are not only unspeakable, they are unimaginable.
 The same situation confronts today us when we try to talk about consciousness and how it relates to matter-energy. Go fishing for consciousness using the net of language and it always, inevitably, slips through the holes in our net. The limits of language-and imagination in talk about consciousness have been recently underlined, yet again, by the exchanges between philosopher Mark Woodhouse and physician Larry Dossey in the pages of Network.
 Essentially, both men take opposing positions regarding the appropriateness of "energy talk" as a way of describing or explaining consciousness or mental phenomena. Woodhouse defends the use of energy talk (and proposes what he seems to think is a novel solution); Dossey denies the appropriateness of talking about consciousness in terms of energy. In for Woodhouse, consciousness is energy ("each is the other"); for Dossey, consciousness is not energy. As a philosopher passionately committed to exploring the relationship between consciousness and matter, between mind and body, and, specifically, the question "Can we have a science of consciousness?" I think the dialogue between Woodhouse and Dossey opens up a crucially important issue for philosophy of mind and for a science of consciousness. I believe the "energy question" is central to any significant advance we may make into understanding consciousness and how it relates to the physical world.
 This relationship, is nevertheless, accredited by a double-aspect perspective: "Energy is the 'outside' of consciousness and consciousness is the 'inside' of energy throughout the universe." But making or that we have fallen into a fundamental philosophical error. As of urging to entice us for which we hold to bind of a particularly atypical sensibility for engaging the encounter with the narratives that belong to some "energy talk" about consciousness. But this study as at times happens to be of something to mention as a double-prospective that foregoes the most important point, and thereby fails to acknowledge what it is of true philosophically and by virtue of its existing character whose value we model.
 A major challenge facing philosophers and scientists of consciousness (and anybody else who wishes to talk about it) is finding appropriate concepts, words and metaphors. So much of our language is derived from our two most dominant senses: vision and touch. Vision feeds language with spatial metaphors, while touch-or rather, kinesthetics-feeds language with muscular push-pull metaphors. The visuo-muscular senses dominate our perception and interaction with the world, and consequently metaphors derived from these senses dominate our ways of conceiving and talking about the world. It is no accident that spatial and mechanical descriptions and explanations predominate in physics-the paradigm science (and our culture's paradigm for all knowledge). Given our evolutionary heritage, with its selective bias toward vision and kinesthetics, we live predominantly in a spatial-push-pull world-the world of classical mechanics, a "billiard-ball" universe of moving, colliding, and recoiling massive bodies. Ours is a world of matter in motion, of things in space acted on by physical forces.
 It should not be surprising, then, that when we come to talk about consciousness, our grooves of thinking channels us toward physics-talk-expressed today as "energy talk." Forces are felt-experienced in the body and we are tempted to think that the experience of force is identical to the energy exchanges between bodies described by physics. But this is to confuse the feeler's feeling (the subject) with what is felt (the object). More on this later.
 Previously mentioned, was that the Woodhouse-Dossey debate highlights yet again the limits of language when we try to talk about consciousness. This problem is at least as old as Descartes' mind-body dualism (though, as we will see, it is not confined to Cartesian dualism-it is there, too, in forms of idealism known as the "Perennial Philosophy"). When Descartes made his famous distinction between mind and matter, he found himself "suspended in the language" of physics. He could find no better way to define mind than negatively in the terminology of physics. He defined matter as that which occupies space"res’ extensa," extended things. He defined the mental world as "res comitans," thinking things-and thinking things differ from physical things in that they do not occupy space. The problem was how could material, physical, things interact with nonphysical things? What conceivably could be the nature of their point of contact-material or mental? Centuries later, Freud, too, resorted to physics-energy talk when to specify the "mechanisms" and dynamics of the psyche-e.g. his concept of the libido. Today, the same tendency to use energy technologically to converse in talking, as Dossey points out, is rife in much new age talk about consciousness, soul, and spirit, exemplified in Woodhouse's article and his book Paradigm Wars.
 Because of our reliance on the senses of vision and kinesthetics, we have an evolutionary predisposition, it seems, to talk in the language of physics or mechanics-and by that I mean "matter talk," or "energy talk." Yet all such talk seems to miss something essential when we come to speak of phenomena in the domain of the mind-for example, emotions, desires, beliefs, pains, and other felt qualities of consciousness. The inappropriate chunkiness of mechanistic metaphors borrowed from classical physics seems obvious enough. The mind just isn't at all like matter or machines, as Descartes was keenly aware. But then came Einstein's relativity, and the quantum revolution. First, Einstein's E = mc2 showed that matter was a form of energy, and so, with the advent of quantum theory, the material world began to dissolve into unimaginable, paradoxical bundles of energy or action. Matter itself was now understood to be a ghostly swirl of energy, and began to take on qualities formerly associated with mind. A great physicist, Sir James Jeans, even declared that "universe begins to look more like a great thought." Quantum events were so tiny, so undetermined, so un-mechanical in the classical sense, they seemed just the sort of thing that could respond to the influence of the mind.
 The quantum-consciousness connection was boosted further by the need (at least in one interpretation of quantum theory) to include the observer (and his/her consciousness) in any complete description of the collapse of the quantum wave function. According to this view, the quantum system must include the consciousness of the observer. Ghostly energy fields from relativity and the quantum-consciousness connection triggered the imaginations of pop-science writers and dabblers in new age pseudo-science: Quantum theory, many believe, has finally opened the way for science to explore and talk about the mind. But the excitement was-and is-premature. It involves the linguistic and conceptual sleight-of-hand, whereas the clucky mechanical language that is in fact a matter that was obviously at best in metaphoric principles, just when applied to consciousness, it now seemed more reasonable to use the language of energy literally-particularly if cloaked in the "spooky" garb of quantum physics. But this shift from "metaphorical matter" to "literal energy" was unwarranted, unfounded, and deceptive.
 Dissolving matter into energy makes neither of them are less conceptual. And the mark of the physical, as Descartes had pointed out, is that it is extended in space. Despite the insuperable problems with his dualism, Descartes' key insight remains valid: What distinguishes mind from matter is precisely that it does not occupy space. And this distinction holds just as fast between mind and energy-even so-called subtle energy (hypothetical "subtle energy" bodies are described as having extension, and other spatial attributes such as waves, vibrations, frequencies). Energy, even in the form of infinitesimal quanta or "subtle vibrations," still occupies space. And any theory of energy as a field clearly makes it spatial. Notions of "quantum consciousness" or "field consciousness"-and Woodhouse's "vibrations," "ripples," or "waves" of consciousness-therefore, are no more than vacuous jargon because they continue to fail to address the very distinction that Descartes formulated nearly four hundred years ago.
 But that's not even the most troublesome deficiency of energy talk. It is equitably to suppose that physicists were proficient to show that quanta of energy did not occupy space; Suppose the behaviour of quanta was so bizarre that they could do all sorts of "non-physical" things-such as transcend space and time; Suppose that even if it could be shown that quanta were not "physical" in Descartes' sense . . . even supposing all of this, any proposed identity between energy and consciousness would still be invalid.
 Energies talk fails to account for what is fundamentally most characteristic about consciousness, namely its subjectivity. No matter how fine-grained, or "subtle," energy could become, as an objective phenomenon it could never account for the fact of subjectivity-the "what-it-feels-like-from-within-experience." Ontologically, subjectivity cannot just emerge from wholly objective reality. Unless energy, at its ontologically most fundamental level, already came with some form of proto-consciousness, proto-experience, or proto-subjectivity, consciousness, experience, or subjectivity would never emerge or evolve in the universe.
 Which brings us to Woodhouse's "energy monism" model, and the notion that "consciousness is the 'inside' of energy throughout the universe." Despite Dossey's criticism of this position, I think Woodhouse is here proposing a version of the only ontology that can account for a universe where both matter-energy and consciousness are real. He briefly summarizes why dualism, idealism, and materialism cannot adequately account for a universe consisting of both matter/energy and consciousness. (He adds "Epiphenomenalism" to these three as though it were distinctly ontological. It is not. Epiphenomenalism is a form of property dualism, which in turn is a form of materialism.) He then proceeds to outline a "fifth" alternative: "Energy monism." And although I believe his fundamental insight is correct, his discussion of this model in terms of double-aspectism falls victim to a common error in metaphysics: He confuses epistemology with ontology.
 Woodhouse proposes that the weaknesses of the other ontologies-dualism, idealism, and materialism-can be avoided by adopting a "double-aspect theory that does not attempt to reduce either energy or consciousness to the other." And he goes on to build his alternative ontology on a double-aspect foundation. Now, I happen to be highly sympathetic with double-aspectism: It is a coherent and comprehensive (even "holistic") epistemology. As a way of knowing the world, double-aspectism opens up the possibility of a complementarity of subjective and objective perspectives.
 But a perspective on the world yields epistemology-it reveals’ something about how we know what we know about the world. It does not reveal the nature of the world, which is the aim of ontology. Woodhouse makes an illegitimate leap from epistemology to ontology when he says, "This [energy monism] is a dualism of perspective, not of fundamental stuff," and concludes that "each is the other." Given his epistemological double-aspectism, the best Woodhouse can claim to be an ontological agnostic (as, in fact, Dossey does). He can talk about viewing the world from two complementary perspectives, but he cannot talk about the nature of the world in itself. Certainly, he cannot legitimately conclude from talk about aspects or perspectives that the ultimate nature of the world is "energy monism" or that "consciousness is energy." Epistemology talk cannot yield ontology talk-as Kant, and later Bohr, were well aware. Kant said we cannot know the thing-in-itself. The best we can hope for is to know some details about the instrument of knowing. Bohr said that the task of quantum physics is not to describe reality as it is in itself, but to describe what we can say about reality.
 The issue of whether energy talk is appropriate for consciousness is to  resolve ontologically not epistemological ly. At issue is whether consciousness is or is not a form of energy-not whether it can be known from different perspectives. If it is a form of energy, then energy talk is legitimate. If not, energy talk is illegitimate. But the nature of consciousness is not to be "determined by perspective," as Woodhouse states: "insides and outsides are determined by perspectives." If "insides" (or "outsides") were merely a matter of perspective, then any ontology would do, as long as we allowed for epistemological dualism or complementarity (though, of course, the meaning of "inside" and "outside" would differ according to each ontology). What Woodhouse doesn't do (which he needs to do to make his epistemology grow ontological legs) has established an ontology compatible with his epistemology of "inside" and "outside." In short, he needs to establish an ontological distinction between consciousness and energy. But this is precisely what Woodhouse aim to avoid with his model of energy monism. Dossey is right, I think, to describe energy talk about consciousness as a legacy of Newtonian physics (i.e., of visuo-kinesthetic mechanics).  This applies equally to "classical energy talk," "quantum-energy talk," "subtle-energy talk," and Woodhouse's "dual-aspect energy talk." In an effort to defend energy talk about consciousness, Woodhouse substitutes epistemology for ontology, and leaves the crucial issue unresolved.
 Unless Woodhouse is willing to ground his double-aspect epistemology in an ontological complementarity that distinguishes mind from matter, but does not separate them, he runs the risk of unwittingly committing "reductionism all over again"-despite his best intentions. In fact, Woodhouse comes very close to proposing just the kind of complementary ontology his model needs: "Consciousness isn't just a different level or wave form of vibrating energy; it is the 'inside' of energy-the pole of interiority perfectly understandable to every person who has had a subjective experience of any kind" (emphasis added). This is ontology talk, not epistemology talk. Woodhouse's error is to claim that the distinction "inside" (consciousness) and "outside" (energy) is merely a matter of perspective.
 In order to defend his thesis of "energy monism," Woodhouse seems to want it both ways. On the one hand, he talks of being conscious and energy being ontologically identical"each is the other"; on the other, he makes a distinction between consciousness and energy: Energy is the 'outside' of consciousness and consciousness is the 'inside' of energy. He attempts to avoid the looming contradiction of consciousness and energy being both "identical yet distinct" by claiming that the identity is ontological while the distinction is epistemological. But the distinction cannot be merely epistemological-otherwise, as already pointed out, any ontology would do. But this is clearly not Woodhouse's position. Energy monism, as proposed by Woodhouse, is an ontological claim. Woodhouse admits as much when he calls energy monism "a fifth alternative" to the ontologism of dualism, idealism, materialism (and Epiphenomenalism [sic]) which he previously dismissed.
 Furthermore, Woodhouse "inside" and "outside" are not merely epistemological when he means them to be synonyms for "subjectivity" and "objectivity" respectively. Although subjectivity and objectivity are epistemological perspectives, they are not only that. Subjectivity and objectivity can have epistemological meaning only if they refer to some implications of a primary ontological distinction-between what Sartre (1956) called the "for-itself" and the "in-itself," between that which feels and that which is felt. Despite his claims to the contrary, Woodhouse's distinction between "inside" and "outside" is ontological-not mere epistemological. And as an ontological distinction between consciousness and energy, it is illegitimate to conclude from his double-aspect epistemology the identity claim that "consciousness is energy." Woodhouse's consciousness-energy monism confusion, it seems to me, is a result of: (1) a failure to distinguish between non-identity and separation, and (2) a desire to avoid the pitfalls of Cartesian dualism. The first is a mistake, the second is not-but he conflates the two. He seems to think that if he allows for a non-identity between consciousness and energy this is tantamount to their being ontologically separate (as in Cartesian dualism). But (1) does not encompass that of (2): Ontological distinction does not entail separation. It is possible to distinguish two phenomena (such as the form and substance of a thing), yet recognize them as inseparable elements of a unity. Unity does not mean identity, and distinction does not mean separation. (I will return to this point shortly.) This muddle between epistemology and ontology is my major criticism of Woodhouse's position. Though if he had the courage or foresight to follow through on his epistemological convictions, and recognize that his position is compatible with (and would be grounded by) an ontological complementarity of consciousness and energy.
The ontological level of understanding (though explicitly denied) in Woodhouse's double-aspect model-where consciousness ("inside") and energy (“outside”) is actual throughout the universe is none other than panpsychism, or what has been variously called pan experientialism (Griffin, 1997) and radical materialism (de Quincey, 1997). It is the fourth alternative to the major ontologism of dualism, idealism, and materialism, and has a very long lineage in the Western philosophical tradition-going all the way back to Aristotle and beyond to the Presocratics. Woodhouse does not acknowledge any of this lineage, as if his double-aspect model was a novel contribution to the mind-matter debate. Besides Aristotle's hylemorphism, he could have referred to Leibniz' monads, Whitehead "actual occasion," and de Chardin's "tangential energy" and the "within" as precursors to the distinction he makes between "inside" and "outside." This oversight weakens the presentation of his case. Of course, to have introduced any or all of these mind-body theories would have made Woodhouse's ontological omission all the more noticeable.
 One other weakness in Woodhouse's article is his reference to the Perennial Philosophy and the Great Chain of Being as supportive of energy talk that unites spiritual and physical realities. "The non-dual Source of some spiritual traditions . . . is said to express itself energetically (outwardly) on different levels in the Great Chain of Being (matter being the densest form of energy) . . ." Woodhouse is here referring to the many variations of idealist emanationism, where spirit is said to pour itself forth through a sequence of ontological levels and condense into matter. But just as I would say Woodhouse's energy monism unwittingly ultimately entails physicalist reductionism, my criticism of emanationism is that it, too, ultimately "physicalizes" spirit-which no idealist worth his or her salt would want to claim. Energy monism runs the same risk of "physicalizing" spirit as emanationism. So I see no support for Woodhouse's position as an alternative to dualism or materialism coming from the Perennial Philosophy. Both run the risk of covert dualism or covert materialism.
 Dossey's critique of Woodhouse's energy monism and energy talk, particularly his caution not to assume that the "nonlocal" phenomena of quantum physics are related to the "nonlocal" phenomena of consciousness and distant healing other than a commonalty of terminology is sound. The caution is wise. However, his critique of Woodhouse's "inside" and "outside" fails to address Woodhouse's confusing epistemology and ontology. If Dossey saw that Woodhouse's intent was to confine the "inside/outside" distinction to epistemology, he might not have couched his critique in ontological terms. Dossey says, "By emphasizing inside and outside, interior and exterior, we merely create new boundaries and interfaces that require their own explanations." The "boundaries and interfaces" Dossey is talking about being ontological, not epistemological. And to this extent, Dossey's critique misses the fact that Woodhouse is explicitly engaged in epistemology talk. On the other hand, Dossey is correct to assume that Woodhouse's epistemological distinction between "inside and outside" necessarily implies an ontological distinction-between "inside" (consciousness) and "outside" energy.
 Dossey's criticism of Woodhouse's energy monism, thus, rests on an ontological objection: Even if we do not yet have any idea of how to talk ontologically about consciousness, we at least know that (despite Woodhouse's contrary claim) consciousness and energy are not ontologically identical. There is an ontological distinction between "inside/consciousness" and "outside/energy." Thus, Dossey concludes, energy talk (which is ontological talk) is inappropriate for consciousness. On this, I agree with Dossey, and disagree with Woodhouse. However, Dossey goes on to take issue with Woodhouse's "inside/outside" distinction as a solution to the mind-body relation. If taken literally, Dossey's criticism is valid: "Instead of grappling with the nature of the connection between energy and consciousness, we are now obliged to clarify the nature of the boundary between 'inside' and 'outside' . . ." But I suspect that Woodhouse uses the spatial concepts "inside/outside" metaphorically because like the rest of us he finds our language short on nonphysical metaphors (though, as we will see, nonspatial metaphors are available).
 It may be, of course, that Woodhouse has not carefully thought through the implications of this spatial metaphor, and how it leaves him open to just the sort of critique that Dossey levels. Dossey, I presume, is as much concerned with Woodhouse's claim that "consciousness is energy," meaning it is the "inside" of energy, as he is about the difficulties in taking the spatial metaphor of "inside/outside" literally. On the first point, I share Dossey's concern. I am less concerned about the second. As long as we remember that talk of "interiority" and "exteriority" are metaphors, I believe they can be very useful ways of pointing toward a crucial distinction between consciousness and energy.
 The metaphor becomes a problem if we slip into thinking that it points to a literal distinction between two kinds of "stuff" (as Descartes did), or indeed to a distinction revealing two aspects of a single kind of "stuff." This latter slip seems to be precisely the mistake that Woodhouse makes with his energy monism. By claiming that consciousness is energy, Woodhouse in effect-despite his best intentions to the contrary-succeeds in equating (and this means "reducing") consciousness to physical "stuff." His mistake-and one that Dossey may be buying into-is to use "stuff-talk" for consciousness. It is a logical error to conclude from (1) there is only one kind of fundamental "stuff" (call it energy), and (2) this "stuff" has an interiority (call it consciousness), that (3) the interiority is also composed of that same "stuff” -, i.e., that consciousness is energy. It could be that "interiority/consciousness" is not "stuff" but something more collectively distinct ontologically-for examples, feeling or process-something which is intrinsic to, and therefore inseparable from, the "stuff." It could be that the world is made up of stuff that feels, where there is an ontological distinction between the feeling (subjectivity, experience, consciousness) and what is felt (objectivity, matter-energy).
 Dossey's rejection of the "inside/outside" metaphor seems to presume (à la Woodhouse) that "inside" means the interior of some "stuff" and is that "stuff"-in this case, energy-stuff. But that is not the position of panpsychist and process philosophers from Leibniz down through Bergson, James, and Whitehead, to Hartshorns and Griffin. If we make the switch from a "stuff-oriented" to a process oriented ontology, then the kind of distinction between consciousness and energy dimly implicit in Woodhouse's model avoids the kind of criticism that Dossey levels at the "inside/outside" metaphor. Process philosophers prefer to use "time-talk" over "space-talk." Instead of talking about consciousness in terms of "insides," they talk about "moments of experience"  or "duration."  Thus, if we view the relationship between consciousness and energy in terms of temporal processes rather than spatial stuff, we can arrive at an ontology similar to Whiteheads relationship between consciousness and energy is understood as temporal. It is the relationship between subjectivity and objectivity, where the subject is the present state of an experiential process, and the object is its prior state. Substitute "present" for "interior" and "past" or "prior" for "exterior" and we have a process ontology that avoids the "boundary" difficulties raised by Dossey. (There is no boundary between past and present-the one flows into the other; the present incorporates the past.) From the perspective of panpsychism or radical materialism, consciousness and energy, mind and matter, subject and object always go together. All matter-energy is intrinsically sentient and experiential. Sentience-consciousness and matter-energy are inseparable, but nevertheless distinct. On this view, consciousness is the process of matter-energy informing itself.
 Although our language is biassed toward physics-energy talk, full of mechanistic metaphors, this is clearly not the whole story. The vernacular of the marketplace, as well as the language of science itself, is also rich with non-mechanistic metaphors, metaphors that flow direct from experience itself. Ironically, not only do we apply these consciousness metaphors to the mind and mental events, but also to the world of matter in our attempts to understand its deeper complexities and dynamics. For example, systems theory and evolutionary biology-even at the reductionist level of molecular genetics-are replete with words such as "codes," "information," "meaning," "self-organizing," and the p-word: "purpose." So we are not limited to mechanistic metaphors when describing either the world of matter or the world of mind. But-and this is the important point-because of our bias toward visuo-muscular images, we tend to forget that metaphors of the mind are sui generis, and, because of our scientific and philosophical bias in favour of a mechanism, we often attempt to reduce metaphors of the mind to metaphors of matter. My proposal for consciousness talk is this: Recognize the limitations of mechanistic metaphors, and the inappropriateness of literal energy talk, when discussing consciousness. Instead, acknowledge the richness and appropriateness of metaphors of meaning when talking about the mind. In short: Drop mechanistic metaphors (energy talk) and take up meaning metaphors (consciousness talk) when talking about consciousness.
 One of the thorniest issues in "energy" and "consciousness" work is the tendency to confuse the two. Consciousness does not equal energy, yet the two are inseparable. Consciousness is the "witness" which experiences the flow of energy, but it is not the flow of energy. We might say consciousness is the felt interiority of energy/matter-but it is not energy.
 If we say that consciousness is a form of energy, then we have two options. Either It is a physical form of energy (even if it is very subtle energy), or It is not a physical form of energy. If we say that consciousness is a form of energy that is physical, then we are reducing consciousness (and spirit) to physics. And few of us, unless we are materialists, want to do that. If we say that consciousness is a form of energy that is not physical, then we need to say in what way psychic energy differs from physical energy. If we cannot explain what we mean by "psychic energy" and how it is different from physical energy, in that then we should ask ourselves why use the term "energy" at all? Our third alternative is to say that consciousness is not a form of energy (physical or nonphysical). This is not to imply that consciousness has nothing to do with energy. In fact, the position I emphasize in my graduate classes is that consciousness and energy always go together. They cannot ever be separated. But this is not to say they are not distinct. They are distinct-energy is energy, consciousness is consciousness-but they are inseparable (like two sides of a coin, or, better, like the shape and substance of a tennis ball. You can't separate the shape from the substance of the ball, but shape and substance are definitely distinct).
 So, for example, if someone has a kundalini experience, they may feel a rush of energy up the chakra system . . . but to say that the energy flow is consciousness is to mistake the object (energy flow) for the subject, for what perceives (consciousness) the object. Note the two importantly distinct words in the phrase "feel the rush of energy . . . " On the one hand there is the "feeling" (or the "feeler"), on the other, there is what is being felt or experienced (the energy). Even our way of talking about it reveals that we detect a distinction between feeling (consciousness) and what we feel (energy). Yes, the two go together, but they are not the same. Unity, or unification, or holism, does not equal identity. To say that one aspect of reality (say, consciousness) cannot be separated from another aspect of reality (say, matter-energy) is not to say both aspects of reality (consciousness and matter-energy) are identical.
 Consciousness, is neither identical to energy (monism) nor it a separate substance or energy in addition to physical matter or energy (dualism)-it is the "interiority," the what-it-feels-like-from-within, the subjectivity that is intrinsic to the reality of all matter and energy (panpsychism or radical materialism). If you take a moment to pay attention to what's going on in your own body right now, you'll see-or feel-what I mean: The physical matter of your body, including the flow of whatever energies are pulsing through you, is the "stuff" of your organism. But there is also a part of you that is aware of, or feels, the pumping of your blood (and other energy streams). That aspect of you that feels the matter-energy in your body is your consciousness. We could express it this way: "Consciousness is the process of matter-energy informing itself." Consciousness is the ability that matter-energy has to feel, to know, and to direct itself. The universe could be (and probably is) full of energy flows, vortices, and vibrations, but without consciousness, all this activity would be completely unfelt and unknown. Only because there is consciousness can the flow of energy be felt, known, and purposefully directed.
 Over the past three decades, philosophy of science has grown increasingly "local." Concerns have switched from general features of scientific practice to concepts, issues, and puzzles specific to particular disciplines. Philosophy of neuroscience is a natural result. This emerging area was also spurred by remarkable recent growth in the neuroscience. Cognitive and computational neuroscience continues to encroach upon issues traditionally addressed within the humanities, including the nature of consciousness, action, knowledge, and normativity. Empirical discoveries about brain structure and function suggest ways that "naturalistic" programs might develop in detail, beyond the abstract philosophical considerations in their favour
 The literature distinguishes "philosophy of neuroscience" and "neurophilosophy." The former concern foundational issues within the neuroscience. The latter concerns application of neuroscientific concepts to traditional philosophical questions. Exploring various concepts of representation employed in neuroscientific theories is an example of the former. Examining implications of neurological syndromes for the concept of a unified self is an example of the latter. In this entry, we will assume this distinction and discuss examples of both.
 Contrary to some opinion, actual neuroscientific discoveries have exerted little influence on the details of materialist philosophies of mind. The "neuroscientific milieu" of the past four decades has made it harder for philosophers to adopt dualism. But even the "type-type" or "central state" identity theories that rose to brief prominence in the late 1950s drew upon few actual details of the emerging neuroscience. Recall the favourite early example of a psychoneural identity claim: pain is identical to C-fibre firing. The "C fibres" turned out to be related to only a single aspect of pain transmission. Early identity theorists did not emphasize psychoneural identity hypotheses, admitting that their "neuro" terms were placeholder for concepts from future neuroscience. Their arguments and motivations were philosophical, even if the ultimate justification of the program was held to be empirical.
 The apology for this lacuna by early identity theorists was that neuroscience at that time was too nascent to provide any plausible identities. But potential identities were afoot. David Hubel and Torsten Wiesel's (1962) electro physiological demonstrations of the receptive field properties of visual neurons had been reported with great fanfare. Using their techniques, neuro physiologists began discovering neurons throughout visual cortex responsive to increasingly abstract features of visual stimuli: from edges to motion direction to colours to properties of faces and hands. More notably, Donald Hebb had published The Organization of Behaviour (1949) a decade earlier. Therein he offered detailed explanations of psychological phenomena in terms of known neural mechanisms and anatomical circuits. His psychological explananda included features of perception, learning, memory, and even emotional disorders. He offered these explanations as potential identities. One philosopher did take note of some available neuroscientific detail was Barbara Von Eckardt-Klein (1975). She discussed the identity theory with respect to sensations of touch and pressure, and incorporated then-current hypotheses about neural coding of sensation modality, intensity, duration, and location as theorized by Mountcastle, Libet, and Jasper. Yet she was a glaring exception. Largely, available neuroscience at the time was ignored by both philosophical friends and foes of early identity theories.
 Philosophical indifference to neuroscientific detail became "principled" with the rise and prominence of functionalism in the 1970s. The functionalists' favourite argument was based on multiple reliability: a given mental state or event can be realized in a wide variety of physical types (Putnam, 1967 and Fodor, 1974). So a detailed understanding of one type of realizing physical system (e.g., brains) will not shed light on the fundamental nature of mind. A psychological state-type is autonomous from any single type of its possible realizing physical mechanisms. Instead of neuroscience, scientifically-minded philosophers influenced by functionalism sought evidence and inspiration from cognitive psychology and "program-writing" artificial intelligence. These disciplines résumé being of themselves  away from underlying physical mechanisms and emphasize the "information-bearing" properties and capacities of representations (Haugeland, 1985). At this same time neuroscience was delving directly into cognition, especially learning and memory. For example, Eric Kandel (1976) proposed parasynaptic mechanisms governing transmitter release rates as a cell-biological explanation of simple forms of associative learning. With Robert Hawkins (1984) he demonstrated how cognitivist aspects of associative learning (e.g., Forming, second-order conditioning, overshadowing) could be explained cell-biologically by sequences and combinations of these basic forms implemented in higher neural anatomies. Working on the postsynaptic side, neuroscientists began unravelling the cellular mechanisms of long term potentiation (LTP). Physiological psychologists quickly noted its explanatory potential for various forms of learning and memory. Yet few "materialist" philosophers paid any attention. Why should they? Most were convinced functionalists, who believed that the "engineering level" details might be important to the clinician, but were irrelevant to the theorist of mind.
 A major turning point in philosophers' interest in neuroscience came with the publication of Patricia Churchland's Neurophilosophy (1986). The Churchlands (Pat and husband Paul) were already notorious for advocating eliminative materialism. In her (1986) book, Churchland distilled eliminativist arguments of the past decade, unified the pieces of the philosophy of science underlying them, and sandwiched the philosophy between a five-chapter introduction and neuroscience and a 70-page chapter on three then-current theories of brain function. She was unapologetic about her intent. She was introducing philosophy of science to neuroscientists and neuroscience to philosophers. Nothing could be more obvious, she insisted, than the relevance of empirical facts about how the brain works to concerns in the philosophy of mind. Her term for this interdisciplinary method was "co-evolution" (borrowed from biology). This method seeks resources and ideas from anywhere on the theory hierarchy above or below the question at issue. Standing on the shoulders of philosophers like Quine and Sellars, Churchland insisted that specifying some point where neuroscience ends and philosophy of science begins is hopeless because the boundaries are poorly defined. neuro philosophers would carefully choose resources from both disciplines as they saw fit.
 Three themes predominate Churchlands philosophical discussion: Developing an alternative to the logical empiricist theory of intertheoretic cause to be connected to property-dualistic arguments based on subjectivity and sensory qualia, and responding to anti-reductionist multiple reliability arguments. These projects have remained central to neurophilosophy over the past decade. John Bickle (1998) extends the principal insight of Clifford Hooker's (1981) post-empiricist theory of intertheoretic reduction. He quantifies key notions using a model-theoretic account of theory structure adapted from the structuralist program in philosophy of science. He also makes explicit the form of argument scientist’s employ to draw ontological conclusions (cross-theoretic identities, revisions, or eliminations) based on the nature of the intertheoretic reduction relations obtaining in specific cases. For example, physicists concluded that visible light, a theoretical posit of optics, is electromagnetic radiation within specified wavelengths, a theoretical posit of electromagnetism: a cross-theoretic ontological identity. In another case, however, chemists concluded that phlogiston did not exist: an elimination of a kind from our scientific ontology. Bickle explicates the nature of the reduction relation in a specific case using a semi-formal account of ‘an interior theoretic approximation’ inspired by structuralist results. Paul Churchland (1996) has carried on the attack on property-dualistic arguments for the ir reducibility of conscious experience and sensory qualia. He argues that acquiring some knowledge of existing sensory neuroscience increases one's ability to ‘imagine’ or ‘conceive of’ a comprehensive neurobiological explanation of consciousness. He defends this conclusion using a thought-experiment based on the history of optics and electromagnetism. Finally, the literature critical of the multiple reliability argument has begun to flourish. Although the multiple reliability argument remains influential among nonreductive physicalists, it no longer commanded the universal acceptance it once did. Replies to the multiple reliability argument based on neuroscientific details have appeared. For example, William Bechtel and Jennifer Mundale (1997, in press) argue that neuroscientists use psychological criteria in brain mapping studies. This fact undercuts the likelihood that psychological kinds are multiplying realized.
 Eliminative materialism (EM) is the conjunction of two claims. First, our common sense ‘belief-desire’ conception of mental events and processes, our ‘folk psychology,’ is a false and misleading account of the causes of human behaviour. Second, like other false conceptual frameworks from both folk theory and the history of science, it will be replaced by, rather than smoothly reduced or incorporated into, a future neuroscience. Folk psychology is the collection of common homilies about the causes of human behaviour. You ask me why Marica is not accompanying me this evening. I reply that her grant deadline is looming. You nod sympathetically. You understand my explanation because you share with me a generalization that relates beliefs about looming deadlines, desires about meeting professionally and financially significant ones, and ensuing free-time behaviour. It is the collection of these kinds of homilies that EM claims to be flawed beyond significant revision. Although this example involves only beliefs and desires, folk psychology contains an extensive repertoire of propositional attitudes in its explanatory nexus: hopes, intentions, fears, imaginings, and more. To the extent that scientific psychology (and neuroscience) retains folk concepts, EM applies to it as well.
 EM is physicalist in the classical sense, postulating some future brain science as the ultimately correct account of (human) behaviour. It is eliminative in predicting the future removal of folk psychological kinds from our post-neuroscientific ontology. EM proponents often employ scientific analogies. Oxidative reactions as characterized within elemental chemistry bear no resemblance to phlogiston release. Even the "direction" of the two processes differ. Oxygen is gained when an object burns (or rusts), phlogiston was said to be lost. The result of this theoretical change was the elimination of phlogiston from our scientific ontology. There is no such thing. For the same reasons, according to EM, continuing development in neuroscience will reveal that there are no such things as beliefs and desires as characterized by common sense.
 Here we focus only on the way that neuroscientific results have shaped the arguments for EM. Surprisingly, only one argument has been strongly influenced. (Most arguments for EM stress the failures of folk psychology as an explanatory theory of behaviour.) This argument is based on a development in cognitive and computational neuroscience that might provide a genuine alternative to the representations and computations implicit in folk psychological generalizations. Many eliminative materialists assume that folk psychology is committed to propositional representations and computations over their contents that mimic logical inferences. Even though discovering such an alternative has been an eliminativist goal for some time, neuroscience only began delivering on this goal over the past fifteen years. Points in and trajectories through vector spaces, as an interpretation of synaptic events and neural activity patterns in biological neural networks are key feature of this development. This argument for EM hinges on the differences between these notions of cognitive representation and the propositional attitudes of folk psychology (Churchland, 1987). However, this argument will be opaque to those with no background in contemporary cognitive and computational neuroscience, so we need to present a few scientific details. With these details in place, we will return to this argument for EM.
 At one level of analysis the basic computational element of a neural network (biological or artificial) is the neuron. This analysis treats neurons as simple computational devices, transforming inputs into output. Both neuronal inputs and outputs reflect biological variables. For the remainder of this discussion, we will assume that neuronal inputs are frequencies of action potentials (neuronal "spikes") in the axons whose terminal branches synapse onto the neuron in question. Neuronal output is the frequency of action potentials in the axon of the neuron in question. A neuron computes its total input (usually treated mathematically as the sum of the products of the signal strength along each input line times the synaptic weight on that line). It then computes a new activation state based on its total input and current activation state, and a new output state based on its new activation value. The neuron's output state is transmitted as a signal strength to whatever neurons on which its axon synapses. The output state reflects systematically the neuron's new activation state.
 Analysed at this level, both biological and artificial neural networks are interpreted naturally as vector-to-vector transformers. The input vector consists of values reflecting activity patterns in axons synapsing on the network's neurons from outside (e.g., from sensory transducers or other neural networks). The output vector consists of values reflecting the activity patterns generated in the network's neurons that project beyond the net (e.g., to motor effectors or other neural networks). Given that neurons' activity depends partly upon their total input, and total input depends partly on synaptic weights (e.g., parasynaptic neurotransmitter release rate, number and efficacy of postsynaptic receptors, availability of enzymes in synaptic cleft), the capacity of biological networks to change their synaptic pressures to initiate a plastic vector-to-vector transformer. In principle, a biological network with plastic synapses can come to implement any vector-to-vector transformation that its composition permits (number of input units, output units, processing layers, recurrence, cross-connections, etc.)
 The anatomical organization of the cerebellum provides a clear example of a network amendable to this computational interpretation. The cerebellum is the bulbous convoluted structure dorsal to the brainstem. A variety of studies (behavioural, neuropsychological, single-cell electros), implicate this structure in motor integration and fine motor coordination. Mossy fibres (axons) from neurons outside the cerebellum synapse on cerebellular granule cells, which in turn project to parallel fibres. Activity patterns’ across the collection of mossy fibres (frequency of action potentials per time unit in each fibre projecting into the cerebellum) provide values for the input vector. Parallel fibres make multiple synapses on the dendritic trees and cell bodies of cerebellular Purkinje neurons. Each Purkinje neuron "sums" its post-synaptic potentials (PSPs) and emits a train of action potentials down its axon based (partly) on its total input and previous activation state. Purkinje axons project outside the cerebellum. The network's output vectors is thus the ordered values representing the pattern of activity generated in each Purkinje axon. Changes to the efficacy of individual synapses on the parallel fibres and the Purkinje neurons alter the resulting PSPs in Purkinje axons, generating different axonal spiking frequencies. Computationally, this amounts to a different output vector to the same input activity pattern (plasticity).
 This interpretation puts the useful mathematical resources of dynamical systems into the hands of computational neuroscientists. Vector spaces are an example. For example, learning can be characterized fruitfully in terms of changes in synaptic weights in the network and subsequent reduction of error in network output. (This approach goes back to Hebb, 1949, although within the vector-space interpretation that follows.) A useful representation of this account is on a synaptic weight-error space, where one dimension represents the global error in the network's output to a given task, and all other dimensions represent the weight values of individual synapses in the network. Points in this multidimensional state space represent the global performance error correlated with each possible collection of synaptic weights in the network. As the weights change with each performance (in accordance with a biologically-implemented learning algorithm), the global error of network performance continually decreases. Learning is represented as synaptic weight changes correlated with a descent along the error dimension in the space (Churchland and Sejnowski, 1992). Representations (concepts) can be portrayed as partitions in multidimensional vector spaces. An example is a neuron activation vector space. A graph of such a space contains one dimension for the activation value of each neuron in the network (or some subset). A point in this space represents one possible pattern of activity in all neurons in the network. Activity patterns generated by input vectors that the network has learned to group together will cluster around a (hyper-) point or sub volume in the activity vector space. Any input pattern sufficiently similar to this group will produce an activity pattern lying in geometrical proximity to this point or sub volume. Paul Churchland (1989) has argued that this interpretation of network activity provides a quantitative, neurally-inspired basis for prototype theories of concepts developed recently in cognitive psychology.
 Using this theoretical development, has offered a novel argument for EM. According to this approach, activity vectors are the central kind of representation and vector-to-vector transformations are the central kind of computation in the brain. This contrasts sharply with the propositional representations and logical/semantic computations postulated by folk psychology. Vectorial content is unfamiliar and alien to common sense. This cross-theoretic difference is at least as great as that between oxidative and phlogiston concepts, or kinetic-corpuscular and caloric fluid heat concepts. Phlogiston and caloric fluid are two "parade" examples of kinds eliminated from our scientific ontology due to the nature of the intertheoretic relation obtaining between the theories with which they are affiliated and the theories that replaced these. The structural and dynamic differences between the folk psychological and emerging cognitive neuroscientific kinds suggest that the theories affiliated with the latter will also correct significantly the theory affiliated with the former. This is the key premise of an eliminativist argument based on predicted intertheoretic relations. And these intertheoretic contrasts are no longer just an eliminativist's goal. Computational and cognitive neuroscience has begun to deliver an alternative kinematics for cognition, one that provides no structural analogue for the propositional attitudes.
 Certainly the replacement of propositional contents by vectorial alternatives implies significant correction to folk psychology. But does it justifies EM? Even though this central feature of folk-psychologically posits in the finding of no analogues in one hot theoretical development in recent cognitive and computational neuroscience, there might be other aspects of cognition that folk psychology gets right. Within neurophilosophy, concluding that a cross-theoretic identity claim is true (e.g., folk psychological state F is identical to neural state N) or that an eliminativist claim is true (there is no such thing as folk psychological state F) depends on the nature of the intertheoretic reduction obtaining between the theories affiliated with the posits in question. But the underlying account of intertheoretic reduction recognizes a spectrum of possible reductions, ranging from relatively "smooth" through "significantly revisionary" to "extremely bumpy." Might the reduction of folk psychology and a "vectorial" neurobiology occupy the middle ground between "smooth" and "bumpy" intertheoretic reductions, and hence suggest a "revisionary" conclusion? The reduction of classical equilibrium thermodynamics to statistical mechanics to microphysics provides a potential analogy. John Bickle  argues on empirical grounds that such a outcome is likely. He specifies conditions on "revisionary" reductions from historical examples and suggests that these conditions are obtaining between folk psychology and cognitive neuroscience as the latter develops. In particular, folk psychology appears to have gotten right the grossly-specified functional profile of many cognitive states, especially those closely related to sensory input and behavioural output. It also appears to get right the "intentionality" of many cognitive states-the object that the state is of or about-even though cognitive neuroscience eschews its implicit linguistic explanation of this feature. Revisionary physicalism predicts significant conceptual change to folk psychological concepts, but denies total elimination of the caloric fluid-phlogiston variety.
 The philosophy of science is another area where vector space interpretations of neural network activity patterns have impacted philosophy. In the Introduction to his (1989) book, Paul Churchland asserts that it will soon be impossible to do serious work in the philosophy of science without drawing on empirical work in the brain and behavioural sciences. To justify this claim, he suggests neurocomputational reformulation of key concepts from this area. At the heart is a neurocomputational account of the structure of scientific theories. Problems with the orthodox "sets-of-sentences" view have been known for more than three decades. Churchland advocates replacing the orthodox view with one inspired by the "vectorial" interpretation of neural network activity. Representations implemented in neural networks (as discussed above) compose a system that corresponds to important distinctions in the external environment, are not explicitly represented as such within the input corpus, and allow the trained network to respond to inputs in a fashion that continually reduces error. These are exactly the functions of theories. Churchland is bold in his assertion: an individual's theory-of-the-world is a specific point in that individual's error-synaptic weight vector space. It is a configuration of synaptic weights that partitions the individual's activation vector space into subdivisions that reduce future error messages to both familiar and novel inputs.
 This reformulation invites an objection, however. Churchland boasts that his theory of theories is preferable to existing alternatives to the orthodox "sets-of-sentences" account-for example, the semantic view (Suppe, 1974; van Fraassen, 1980)-because his is closer to the "buzzing brains" that use theories. But as Bickle notes, neurocomputational models based on the mathematical resources described above are a long way into the realm of abstractia. Even now, they remain little more than novel (and suggestive) applications of the mathematics of quasi-linear dynamical system to simplified schemata of brain circuitries. neuro philosophers owe some account of identifications across ontological categories before the philosophy of science community will accept the claim that theories are points in high-dimensional state spaces implemented in biological neural networks. (There is an important methodological assumption lurking in this objection.
 Churchlands neurocomputational reformulation of scientific and epistemological concepts build on this account of theories. He sketches "neutralized" accounts of the theory-ladenness of perception, the nature of concept unification, the virtues of theoretical simplicity, the nature of Kuhnian paradigms, the kinematics of conceptual change, the character of abduction, the nature of explanation, and even moral knowledge and epistemological normativity. Conceptual redeployment, for example, is the activation of an already-existing prototype representation-a counterpoint or region of a partition of a high-dimensional vector space in a trained neural network-a novel type of input pattern. Obviously, we can't here do justice to Churchlands various attempts at reformulation. We urge the intrigued reader to examine his suggestions in their original form. But a word about philosophical methodology is in order. Churchland is not attempting "conceptual analysis" in anything resembling its traditional philosophical sense and neither, typically, are neuro philosophers. (This is why a discussion of neuro philosophical reformulation fits with a discussion of EM.) There are philosophers who take the discipline's ideal to be a relatively simple set of necessary and sufficient conditions, expressed in non-technical natural language, governing the application of important concepts (like justice, knowledge, theory, or explanation). These analyses should square, to the extent possible, with pre-theoretical usage. Ideally, they should preserve synonymy. Other philosophers view this ideal as sterile, misguided, and perhaps deeply mistaken about the underlying structure of human knowledge. neuro philosophers tend to reside in the latter camp. Those who dislike philosophical speculation about the promise and potential of nascent science in an effort to reformulate ("reform-ulate") traditional philosophical concepts have probably already discovered that neurophilosophy is not for them. But the charge that neurocomputational reformulation of the sort Churchland attempts are "philosophically uninteresting" or "irrelevant" because they fail to provide "adequate analyses" of theory, explanation, and the like will get ignored among many contemporary philosophers, as well as their cognitive-scientific and neuroscientific friends. Before we leave the neuro philosophical applications of this theoretical development from recent cognitive/computational neuroscience, one more point of scientific detail is in order. The popularity of treating the neuron as the basic computational unit among neural modelers, as opposed to cognitive modelers, is declining rapidly. Compartmental modelling enables computational neuroscientists to mimic activity in and interactions between patches of neuronal membrane. This endorses modelers to control and manipulate a variety of subcellular factors that determine action potentials per time unit (including the topology of membrane structure in individual neurons, variations in ion channels across membrane patches, field properties of post-synaptic potentials depending on the location of the synapse on the dendrite or soma). Modelers can "custom-build" the neurons in their target circuitry without sacrificing the ability to study circuit properties of networks. For these reasons, few serious computational neuroscientists continue to work at a level that treats neurons as unstructured computational devices. But the above interpretative points still stand. With compartmental modelling, not only are simulated neural networks interpretable as vector-to-vector transformers. The neurons composing them are, too.
 The Philosophy of science, and scientific epistemology are not the only area where philosophers have lately urged the relevance of neuroscientific discoveries. Kathleen Akins argues that a "traditional" view of the senses underlies the variety of sophisticated "naturalistic" programs about intentionality. Current neuroscientific understanding of the mechanisms and coding strategies implemented by sensory receptors shows that this traditional view is mistaken. The traditional view holds that sensory systems are "veridical" in at least three ways. (1) Each signal in the system correlates with a small range of properties in the external (to the body) environment. (2) The structure in the relevant relations between the external properties the receptors are sensitive to is preserved in the structure of the relations between the resulting sensory states. And (3) the sensory system reconstructively in faithfully, without fictive additions or embellishments, the external events. Using recent neurobiological discoveries about response properties of thermal receptors in the skin as an illustration, Akins shows that sensory systems are "narcissistic" rather than "veridical." All three traditional assumptions are violated. These neurobiological details and their philosophical implications open novel questions for the philosophy of perception and for the appropriate foundations for naturalistic projects about intentionality. Armed with the known neurophysiology of sensory receptors, for example, our "philosophy of perception" or of "perceptual intentionality" will no longer focus on the search for correlations between states of sensory systems and "veridically detected" external properties. This traditional philosophical (and scientific) project rests upon a mistaken "veridical" view of the senses. Neuroscientific knowledge of sensory receptor activity also shows that sensory experience does not serve the naturalist well as a "simple paradigm case" of an intentional relation between representation and world. Once again, available scientific detail shows the naivety of some traditional philosophical projects.
 Focussing on the anatomy and physiology of the pain transmission system, Valerie Hardcastle (1997) urges a similar negative implication for a popular methodological assumption. Pain experiences have long been philosophers' favourite cases for analysis and theorizing about conscious experience generally. Nevertheless, every position about pain experiences has been defended recently: eliminativist, a variety of objectivists view, relational views, and subjectivist views. Why so little agreement, despite agreement that pain experience is the place to start an analysis or theory of consciousness? Hardcastle urges two answers. First, philosophers tend to be uninformed about the neuronal complexity of our pain transmission systems, and build their analyses or theories on the outcome of a single component of a multi-component system. Second, even those who understand some of the underlying neurobiology of pain tends to advocate gate-control theories. But the best existing gate-control theories are vague about the neural mechanisms of the gates. Hardcastle instead proposes a dissociable dual system of pain transmission, consisting of a pain sensory system closely analogous in its neurobiological implementation to other sensory systems, and a descending pain inhibitory system. She argues that this dual system is consistent with recent neuroscientific discoveries and accounts for all the pain phenomena that have tempted philosophers toward particular (but limited) theories of pain experience. The neurobiological uniqueness of the pain inhibitory system, contrasted with the mechanisms of other sensory modalities, renders pain processing atypical. In particular, the pain inhibitory system dissociates pains sensation from stimulation of nociceptors (pain receptors). Hardcastle concludes from the neurobiological uniqueness of pain transmission that pain experiences are atypical conscious events, and hence not a good place to start theorizing about or analysing the general type.
 Developing and defending theories of content is a central topic in current philosophy of mind. A common desideratum in this debate is a theory of cognitive representation consistent with a physical or naturalistic ontology. We'll here describe a few contributions neuro philosophers have made to this literature.
 When one perceives or remembers that he is out of coffee, his brain state possesses intentionality or "aboutness." The percept or memory is about one's being out of coffee, and it represents one for being out of coffee. The representational state has content. A psychosemantics seeks to explain what it is for a representational state to be about something: to provide an account of how states and events can have specific representational content. A physicalist psychosemantics seeks to do this using resources of the physical sciences exclusively. neuro philosophers have contributed to two types of physicalist psychosemantics: the Functional Role approach and the Informational approach.
 The core claim of functional roles of semantics holds that a representation has its content in virtue of relations it bears to other representations. Its paradigm application is to concepts of truth-functional logic, like the conjunctive ‘and’ or disjunctive ‘or.’ A physical event instantiates the ‘and’ function just in case it maps two true inputs onto a single true output. Thus an expression bears the relations to others that give it the semantic content of ‘and.’ Proponents of functional role semantics propose similar analyses for the content of all representations (Form 1986). A physical event represents birds, for example, if it bears the right relations to events representing feathers and others representing beaks. By contrast, informational semantics associates content to a state depending upon the causal relations obtaining between the state and the object it represents. A physical state represents birds, for example, just in case an appropriate causal relation obtains between it and birds. At the heart of informational semantics is a causal account of information. Red spots on a face carry the information that one has measles because the red spots are caused by the measles virus. A common criticism of informational semantics holds that mere causal covariation is insufficient for representation, since information (in the causal sense) is by definition, always veridical while representations can misrepresent. A popular solution to this challenge invokes a teleological analysis of ‘function.’ A brain state represents X by virtue of having the function of carrying information about being caused by X (Dretske 1988). These two approaches do not exhaust the popular options for a psychosemantics, but are the ones to which neuro philosophers have contributed.
 Paul Churchlands allegiance to functional role semantics goes back to his earliest views about the semantics of terms in a language. In his (1979) book, he insists that the semantic identity (content) of a term derive from its place in the network of sentences of the entire language. The functional economies envisioned by early functional role semanticists were networks with nodes corresponding to the objects and properties denoted by expressions in a language. Thus one node, appropriately connected, might represent birds, another feathers, and another beaks. Activation of one of these would tend to spread to the others. As ‘connectionist’ network modelling developed, alternatives arose to this one-representation-per-node ‘localist’ approach. By the time Churchland provided a neuroscientific elaboration of functional role semantics for cognitive representations generally, he too had abandoned the ‘localist’ interpretation. Instead, he offered a ‘state-space semantics’.
 We saw in the section just above how (vector) state spaces provide a natural interpretation for activity patterns in neural networks (biological and artificial). A state-space semantics for cognitive representations is a species of functional role semantics because the individuation of a particular state depends upon the relations obtaining between it and other states. A representation is a point in an appropriate state space, and points (or sub volumes) in a space are individuated by their relations to other points (locations, geometrical proximity). Churchland illustrates a state-space semantics for neural states by appealing to sensory systems. One popular theory in sensory neuroscience of how the brain codes for sensory qualities (like Collor) are the opponent process account. Churchland describes a three-dimensional activation vector state-space in which all Collor perceivable by humans is represented as a point (or sub value). Each dimension corresponds to activity rates in one of three classes of photoreceptors present in the human retina and their efferent paths: The red-green opponent pathway, yellow-blue opponent pathway, and black-white (contrast) opponent pathway. Photons striking the retina are transduced by the receptors, producing an activity rate in each of the segregated pathways. The characterized Cellos have a triplet of activation frequency rates. Each dimension in that three-dimensional space will represent average frequency of action potentials in the axons of one class of ganglion cells projecting out of the retina. Face-to-face, the Collor perceivable by humans will be a region of that space. For example, an orange stimulus produces a relatively low level of activity in both the red-green and yellow-blue opponent pathways (x-axis and y-axis, respectively), and middle-range activity in the black-white (contrast) opponent pathways (z-axis). Pink stimuli, on the other hand, produce low activity in the red-green opponent pathway, middle-range activity in the yellow-blue opponent pathway, and high activity in the black-white (contrast) an opponent pathway. The location of each colour in the space generates a ‘colour solid.’ Location on the solid and geometrical proximity between regions reflect structural similarities between the perceived colours. Human gustatory representations are points in a four-dimensional state space, with each dimension coding for activity rates generated by gustatory stimuli in each type of taste receptor (sweet, salty, sour, bitter) and their segregated efferent pathways. When implemented in a neural network with structural and hence computational resources as vast as the human brain, the state space approach to psychosemantics generates a theory of content for a huge number of cognitive states.
 Jerry Fodor and Ernest LePore  raise an important challenge to Churchlands psychosemantics. Location in a state space alone seems insufficient to fix a state's representational content. Churchland never explains why a point in a three-dimensional state space represents the Collor, as opposed to any other quality, object, or event that varies along three dimensions. Churchlands account achieves its explanatory power by the interpretation imposed on the dimensions. Fodor and LePore allege that Churchland never specifies how a dimension comes to represent, e.g., degree of saltiness, as opposed to yellow-blue wavelength opposition. One obvious answer appeals to the stimuli that form the ‘external’ inputs to the neural network in question. Then, for example, the individuating conditions on neural representations of colours are that opponent processing neurons receive input from a specific class of photoreceptors. The latter in turn have electromagnetic radiation (of a specific portion of the visible spectrum) as their activating stimuli. However, this appeal to ‘external’ stimuli as the ultimate individuating conditions for representational content makes the resulting approach a version of informational semantics. Is this approach consonant with other neurobiological details?
 The neurobiological paradigm for informational semantics is the feature detector: One or more neurons that are (i) maximally responsive to a particular type of stimulus, and (ii) have the function of indicating the presence of that stimulus type. Examples of such stimulus-types for visual feature detectors include high-contrast edges, motion direction, and colours. A favourite feature detector among philosophers is the alleged fly detector in the frog. Lettvin et al. (1959) identified cells in the frog retina that responded maximally to small shapes moving across the visual field. The idea that these cells' activity functioned to detect flies rested upon knowledge of the frogs' diet. Using experimental techniques ranging from single-cell recording to sophisticated functional imaging, neuroscientists have recently discovered a host of neurons that are maximally responsive to a variety of stimuli. However, establishing condition (ii) on a feature detector is much more difficult. Even some paradigm examples have been called into question. David Hubel and Torsten Wiesel's (1962) Nobel Prize winning work establishing the receptive fields of neurons in striate cortices are often interpreted as revealing cells whose function is edge detection. However, Lehky and Sejnowski (1988) have challenged this interpretation. They trained an artificial neural network to distinguish the three-dimensional shape and orientation of an object from its two-dimensional shading pattern. Their network incorporates many features of visual neurophysiology. Nodes in the trained network turned out to be maximally responsive to edge contrasts, but did not appear to have the function of edge detection.
 Kathleen Akins (1996) offers a different neuro philosophical challenge to informational semantics and its affiliated feature-detection view of sensory representation. We saw in the previous section how Akins argues that the physiology of thermoreceptor violates three necessary conditions on ‘veridical’ representation. From this fact she draws doubts about looking for feature detecting neurons to ground a psychosemantics generally, including thought contents. Human thoughts about flies, for example, are sensitive to numerical distinctions between particular flies and the particular locations they can occupy. But the ends of frog nutrition are well served without a representational system sensitive to such ontological refinements. Whether a fly seen now is numerically identical to one seen a moment ago, need not, and perhaps cannot, figure into the frog's feature detection repertoire. Akins' critique casts doubt on whether details of sensory transduction will scale up to encompass of some adequately unified psychosemantics. It also raises new questions for human intentionality. How do we get from activity patterns in "narcissistic" sensory receptors, keyed not to "objective" environmental features but rather only to effects of the stimuli on the patch of tissue enervative, to the human ontology replete with enduring objects with stable configurations of properties and relations, types and their tokens (as the "fly-thought" example presented above reveals), and the rest? And how did the development of a stable, and rich ontology confer survival advantages to human ancestors?
 Consciousness has reemerged as a topic in philosophy of mind and the cognitive and brain sciences over the past three decades. Instead of ignoring it, many physicalists now seek to explain it (Dennett, 1991). Here we focus exclusively on ways those neuroscientific discoveries have impacted philosophical debates about the nature of consciousness and its relation to physical mechanisms. Thomas Nagel argues that conscious experience is subjective, and thus permanently recalcitrant to objective scientific understanding. He invites us to ponder ‘what it is like to be a bat’ and urges the intuition that no amount of physical-scientific knowledge (including neuroscientific) supplies a complete answer. Nagel's intuition pump has generated extensive philosophical discussion. At least two well-known replies make direct appeal to neurophysiology. John Biro suggests that part of the intuition pumped by Nagel, that bat experience is substantially different from human experience, presupposes systematic relations between physiology and phenomenology. Kathleen Akins (1993a) delves deeper into existing knowledge of bat physiology and reports much that is pertinent to Nagel's question. She argues that many of the questions about bat subjectivity that we still consider open hinge on questions that remain unanswered about neuroscientific details. One example of the latter is the function of various cortical activity profiles in the active bat.
 More recently philosopher David Chalmers (1996) has argued that any possible brain-process account of consciousness will leave open an ‘explanatory gap’ between the brain process and properties of the conscious experience. This is because no brain-process theory can answer the "hard" question: Why should that particular brain process give rise to conscious experience? We can always imagine ("conceive of") a universe populated by creatures having those brain processes but completely lacking conscious experience. A theory of consciousness requires an explanation of how and why some brain process causes consciousness replete with all the features we commonly experience. The fact that the hard question remains unanswered shows that we will probably never get a complete explanation of consciousness at the level of neural mechanisms. Paul and Patricia Churchland have recently offered the following diagnosis and reply. Chalmers offer a conceptual argument, based on our ability to imagine creatures possessing brains like ours but wholly lacking in conscious experience. But the more one learns about how the brain produces conscious experience-and literature is beginning to emerge (e.g., Gazzaniga, 1995)-the harder it becomes to imagine a universe consisting of creatures with brain processes like ours but lacking consciousness. This is not just to bare assertions. The Churchlands appeal to some neurobiological detail. For example, Paul Churchland (1995) develops a neuroscientific account of consciousness based on recurrent connections between thalamic nuclei (particularly "diffusely projecting" nuclei like the intralaminar nuclei) and the cortex. Churchland argues that the thalamocortical recurrency accounts for the selective features of consciousness, for the effects of short-term memory on conscious experience, for vivid dreaming during REM. (rapid-eye movement) sleep, and other "core" features of conscious experience. In other words, the Churchlands are claiming that when one learns about activity patterns in these recurrent circuits, one can't "imagine" or "conceive of" this activity occurring without these core features of conscious experience. (Other than just mouthing the words, "I am now imagining activity in these circuits without selective attention/the effects of short-term memory/vivid dreaming . . . ")
 A second focus of sceptical arguments about a complete neuroscientific explanation of consciousness is sensory qualia: the introspectable qualitative aspects of sensory experience, the features by which subjects discern similarities and differences among their experiences. The colours of visual sensations are a philosopher's favourite example. One famous puzzle about colour qualia is the alleged conceivability of spectral inversions. Many philosophers claim that it is conceptually possible (if perhaps physically impossible) for two humans not to differ neurophysiological, while the Collor that fire engines and tomatoes appear to have to one subject is the Collor that grass and frogs appear to have to the other (and vice versa). A large amount of neuroscientifically-informed philosophy has addressed this question. A related area where neurophilosophical considerations have emerged concerns the metaphysics of colours themselves (rather than Collor experiences). A longstanding philosophical dispute is whether colours are objective property’s Existing external to perceiver or rather identifiable as or dependent upon minds or nervous systems. Some recent work on this problem begins with characteristics of Collor experiences: For example that Collor similarity judgments produce Collor orderings that align on a circle. With this resource, one can seek mappings of phenomenology onto environmental or physiological regularities. Identifying colours with particular frequencies of electromagnetic radiation does not preserve the structure of the hue circle, whereas identifying colours with activity in opponent processing neurons does. Such a tidbit is not decisive for the Collor objectivist-subjectivist debate, but it does convey the type of neurophilosophical work being done on traditional metaphysical issues beyond the philosophy of mind.
 We saw in the discussion of Hardcastle (1997) two sections above that Neurophilosophers have entered disputes about the nature and methodological import of pain experiences. Two decades earlier, Dan Dennett (1978) took up the question of whether it is possible to build a computer that feels pain. He compares and notes pressure between neurophysiological discoveries and common sense intuitions about pain experience. He suspects that the incommensurability between scientific and common sense views is due to incoherence in the latter. His attitude is wait-and-see. But foreshadowing Churchland's reply to Chalmers, Dennett favours scientific investigations over conceivability-based philosophical arguments.
 Neurological deficits have attracted philosophical interest. For thirty years philosophers have found implications for the unity of the self in experiments with commissurotomy patients. In carefully controlled experiments, commissurotomy patients display two dissociable seats of consciousness. Patricia Churchland scouts philosophical implications of a variety of neurological deficits. One deficit is blind-sight. Some patients with lesions to primary visual cortex report being unable to see items in regions of their visual fields, yet perform far better than chance in forced guess trials about stimuli in those regions. A variety of scientific and philosophical interpretations have been offered. Ned Form (1988) worries that many of these conflate distinct notions of consciousness. He labels these notions ‘phenomenal consciousness’ (‘P-consciousness’) and ‘access consciousness’ (‘A-consciousness’). The former is that which, ‘what it is like-ness of experience. The latter is the availability of representational content to self-initiated action and speech. Form argues that P-consciousness is not always representational whereas A-consciousness is. Dennett and Michael Tye  are sceptical of non-representational analyses of consciousness in general. They provide accounts of blind-sight that do not depend on Form's distinction.
 Many other topics are worth neurophilosophical pursuit. We mentioned commissurotomy and the unity of consciousness and the self, which continues to generate discussion. Qualia beyond those of Collor and pain have begun to attract neurophilosophical attention has self-consciousness. The first issues to arise in the ‘philosophy of neuroscience’ (before there was a recognized area) was the localization of cognitive functions to specific neural regions. Although the ‘localization’ approach had dubious origins in the phrenology of Gall and Spurzheim, and was challenged severely by Flourens throughout the early nineteenth century, it reemerged in the study of aphasia by Bouillaud, Auburtin, Broca, and Wernicke. These neurologists made careful studies (where possible) of linguistic deficits in their aphasic patients followed by brain autopsies postmortem. Broca's initial study of twenty-two patients in the mid-nineteenth century confirmed that damage to the left cortical hemisphere was predominant, and that damage to the second and third frontal convolutions was necessary to produce speech production deficits. Although the anatomical coordinates’ Broca postulates for the ‘speech production centres do not correlate exactly with damage producing production deficits, both are that in this area of frontal cortex and speech production deficits still bear his name (‘Broca's area’ and ‘Broca's aphasia’). Less than two decades later Carl Wernicke published evidence for a second language centre. This area is anatomically distinct from Broca's area, and damage to it produced a very different set of aphasic symptoms. The cortical area that still bears his name (‘Wernicke's area’) is located around the first and second convolutions in temporal cortex, and the aphasia that bears his name (‘Wernicke's aphasia’) involves deficits in language comprehension. Wernicke's method, like Broca's, was based on lesion studies: a careful evaluation of the behavioural deficits followed by post mortem examination to find the sites of tissue damage and atrophy. Lesion studies suggesting more precise localization of specific linguistic functions remain a cornerstone to this day in aphasic research
 Lesion studies have also produced evidence for the localization of other cognitive functions: for example, sensory processing and certain types of learning and memory. However, localization arguments for these other functions invariably include studies using animal models. With an animal model, one can perform careful behavioural measures in highly controlled settings, then ablate specific areas of neural tissue (or use a variety of other techniques to Form or enhance activity in these areas) and remeasure performance on the same behavioural tests. But since we lack an animal model for (human) language production and comprehension, this additional evidence isn't available to the neurologist or neurolinguist. This fact makes the study of language a paradigm case for evaluating the logic of the lesion/deficit method of inferring functional localization. Philosopher Barbara Von Eckardt (1978) attempts to make explicit the steps of reasoning involved in this common and historically important method. Her analysis begins with Robert Cummins' early analysis of functional explanation, but she extends it into a notion of structurally adequate functional analysis. These analyses break down a complex capacity C into its constituent capacity’s c1, c2, . . .  cn, where the constituent capacities are consistent with the underlying structural details of the system. For example, human speech production (complex capacity C) results from formulating a speech intention, then selecting appropriate linguistic representations to capture the content of the speech intention, then formulating the motor commands to produce the appropriate sounds, then communicating these motor commands to the appropriate motor pathways (constituent capacity’s c1, c2, . . . , cn). A functional-localization hypothesis has the form: Brain structure S in an organism (type) O has constituent capacity ci, where ci is a function of some part of O. An example, Brains Broca's area (S) in humans (O) formulates motor commands to produce the appropriate sounds (one of the constituent capacities ci). Such hypotheses specify aspects of the structural realization of a functional-component model. They are part of the theory of the neural realization of the functional model.
 Armed with these characterizations, Von Eckardt argues that inference to a functional-localization hypothesis proceeds in two steps. First, a functional deficit in a patient is hypothesized based on the abnormal behaviour the patient exhibits. Second, localization of function in normal brains is inferred on the basis of the functional deficit hypothesis plus the evidence about the site of brain damage. The structurally-adequate functional analysis of the capacity connects the pathological behaviour to the hypothesized functional deficit. This connection suggests four adequacy conditions on a functional deficit hypothesis. First, the pathological behaviour P (e.g., the speech deficits characteristic of Broca's aphasia) must result from failing to exercise some complex capacity C (human speech production). Second, there must be a structurally-adequate functional analysis of how people exercise capacity C that involves some constituent capacity ci (formulating motor commands to produce the appropriate sounds). Third, the operation of the steps described by the structurally-adequate functional analysis minus the operation of the component performing ci (Broca's area) must result in pathological behaviour P. Fourth, there must not be a better available explanation for why the patient does P. Arguments to a functional deficit hypothesis on the basis of pathological behaviour is thus an instance of argument to the best available explanation. When postulating a deficit in a normal functional component provides the best available explanation of the pathological data, we are justified in drawing the inference.
 Von Eckardt applies this analysis to a neurological case study involving a controversial reinterpretation of agnosia. Her philosophical explication of this important neurological method reveals that most challenges to localization arguments of whether to argue only against the localization of a particular type of functional capacity or against generalizing from localization of function in one individual to all normal individuals. (She presents examples of each from the neurological literature.) Such challenges do not impugn the validity of standard arguments for functional localization from deficits. It does not follow that such arguments are unproblematic. But they face difficult factual and methodological problems, not logical ones. Furthermore, the analysis of these arguments as involving a type of functional analysis and inference to the best available explanation carries an important implication for the biological study of cognitive function. Functional analyses require functional theories, and structurally adequate functional analyses require checks imposed by the lower level sciences investigating the underlying physical mechanisms. Arguments to best available explanation are often hampered by a lack of theoretical imagination: the available explanations are often severely limited. We must seek theoretical inspiration from any level of theory and explanation. Hence making explicit the ‘logic’ of this common and historically important form of neurological explanation reveals the necessity of joint participation from all scientific levels, from cognitive psychology down to molecular neuroscience. Von Eckardt anticipated what came to be heralded as the ‘co-evolutionary research methodology,’ which remains a centerpiece of neurophilosophy to the present day.
 Over the last two decades, evidence for localization of cognitive function has come increasingly from a new source: the development and refinement of neuroimaging techniques. The form of localization-of-function argument appears not to have changed from that employing lesion studies (as analysed by Von Eckardt). Instead, these imaging technologies resolve some of the methodological problems that plage lesion studies. For example, researchers do not need to wait until the patient dies, and in the meantime probably acquires additional brain damage, to find the lesion sites. Two functional imaging techniques are prominent: Positron emission tomography, or PET, and functional magnetic resonance imaging, or MRI. Although these measure different biological markers of functional activity, both now have a resolution down to around 1mm.  As these techniques increase spatial and temporal resolution of functional markers and continue to be used with sophisticated behavioural methodologies, the possibility of localizing specific psychological functions to increasingly specific neural regions continues to grow
 What we now know about the cellular and molecular mechanisms of neural conductance and transmission is spectacular. The same evaluation holds for all levels of explanation and theory about the mind/brain: maps, networks, systems, and behaviour. This is a natural outcome of increasing scientific specialization. We develop the technology, the experimental techniques, and the theoretical frameworks within specific disciplines to push forward our understanding. Still, a crucial aspect of the total picture gets neglected: the relationship between the levels, the ‘glue’ that binds knowledge of neuron activity to subcellular and molecular mechanisms, network activity patterns to the activity of and connectivity between single neurons, and behaviour to network activity. This problem is especially glaring when we focus on the relationship between ‘cognitivist’ psychological theories, postulating information-bearing representations and processes operating over their contents, and the activity patterns in networks of neurons. Co-evolution between explanatory levels still seems more like a distant dream rather than an operative methodology.
 It is here that some neuroscientists appeal to ‘computational’ methods. If we examine the way that computational models function in more developed sciences (like physics), we find the resources of dynamical systems constantly employed. Global effects (such as large-scale meteorological patterns) are explained in terms of the interaction of ‘local’ lower-level physical phenomena, but only by dynamical, nonlinear, and often chaotic sequences and combinations. Addressing the interlocking levels of theory and explanation in the mind/brain using computational resources that have worked to bridge levels in more mature sciences might yield comparable results. This methodology is necessarily interdisciplinary, drawing on resources and researchers from a variety of levels, including higher levels like experimental psychology, ‘program-writing’ and ‘connectionist’ artificial intelligence, and philosophy of science.
 However, the use of computational methods in neuroscience is not new. Hodgkin, Huxley, and Katz incorporated values of voltage-dependent potassium conductance they had measured experimentally in the squid giant axon into an equation from physics describing the time evolution of a first-order kinetic process. This equation enabled them to calculate best-fit curves for modelled conductance versus time data that reproduced the S-shaped (sigmoidal) function suggested by their experimental data. Using equations borrowed from physics, Rall (1959) developed the cable model of dendrites. This theory provided an account of how the various inputs from across the dendritic tree interact temporally and spatially to determine the input-output properties of single neurons. It remains influential today, and has been incorporated into the genesis software for programming neurally realistic networks. More recently, David Sparks and his colleagues have shown that a vector-averaging model of activity in neurons of superior colliculi correctly predicts experimental results about the amplitude and direction of saccadic eye movements. Working with a more sophisticated mathematical model, Apostolos Georgopoulos and his colleagues have predicted direction and amplitude of hand and arm movements based on averaged activity of 224 cells in motor cortices. Their predictions have borne out under a variety of experimental tests. We mention these particular studies only because we are familiar with them. We could multiply examples of the fruitful interaction of computational and experimental methods in neuroscience easily by one-hundred-fold. Many of these extend back before ‘computational neuroscience’ was a recognized research endeavour.
 We've already seen one example, the vector transformation account, of neural representation and computation, under active development in cognitive neuroscience. Other approaches using ‘cognitivist’ resources are also being pursued.  Many of these projects draw upon ‘cognitivist’ characterizations of the phenomena to be explained. Many exploit ‘cognitivist’ experimental techniques and methodologies. Some even attempt to derive ‘cognitivist’ explanations from cell-biological processes (e.g., Hawkins and Kandel 1984). As Stephen Kosslyn puts it, cognitive neuroscientists employ the ‘information processing’ view of the mind characteristic of cognitivism without trying to separate it from theories of brain mechanisms. Such an endeavour calls for an interdisciplinary community willing to communicate the relevant portions of the mountain of detail gathered in individual disciplines with interested nonspecialists: not just people willing to confer with those working at related levels, but researchers trained in the methods and factual details of a variety of levels. This is a daunting requirement, but it does offer some hope for philosophers wishing to contribute to future neuroscience. Thinkers trained in both the ‘synoptic vision’ afforded by philosophy and the factual and experimental basis of genuine graduate-level science would be ideally equipped for this task. Recognition of this potential niche has been slow among graduate programs in philosophy, but there is some hope that a few programs are taking steps to fill it.
 In the final analysis there will be philosophers unprepared to accept that, if a given cognitive capacity is psychologically real, then there must be an explanation of how it is possible for an individual in the course of human development to acquire that cognitive capacity, or anything like it, can have a role to play in philosophical accounts of concepts and conceptual abilities. The most obvious basis for such a view would be a Frégean distrust of “psychology” that leads to a rigid division of labour between philosophy and psychology. The operative thought is that the task of a philosophical theory of concepts is to explain what a given concept is or what a given conceptual ability consist in. This, it is frequently maintained, is something that can be done in complete independence of explaining how such a concept or ability might be acquired. The underlying distinction is one between philosophical questions centring around concept possession and psychological questions centring around concept possibilities for an individual to acquire that ability, then it cannot be psychologically real. Nevertheless, this distinction is, however, strictly one does adhere to the distinction, it provides no support for a rejection of any given cognitive capacity for which is psychologically real. The neo-Frégean distinction is directly against the view that facts about how concepts are acquired have a role to play in explaining and individualizing concepts. But this view does not have to be disputed by a supporter as such, nonetheless, all that the supporter is to commit is that the principle that no satisfactory account of what a concept is should make it impossible to provide explanation of how that concept can be acquired. That is, that this principle has nothing to say about the further question of whether the psychological explanation has a role to play in a constitutive explanation of the concept, and hence is not in conflict with the neo-Frégean distinction.
 A full account of the structure of consciousness, will need to illustrate those higher, conceptual forms of consciousness to which little attention on such an account will take and about how it might emerge from given points of value, is the thought that an explanation of everything that is distinctive about consciousness will emerge out of an account of what it is for a subject to be capable of thinking about himself. But, to a proper understanding of the complex phenomenon of consciousness. There are no facts about linguistic mastery that will determine or explain what might be termed the cognitive dynamics that are individual processes that have found their way forward for a theory of consciousness, it sees, to chart the characteristic features individualizing the various distinct conceptual forms of consciousness in a way that will provide a taxonomy of unconsciousness and they, to show how these manifest the characterlogical functions a can to determine at the level of content. What is hoped is now clear is that these forms of higher forms of consciousness emerge from a rich foundation of non-conceptual representations of thought, which can only expose and clarify their conviction that these forms of conscious thought hold the key, not just to an eventful account of how mastery of the conscious paradigms, but to a proper understanding of the plexuity of self-consciousness and/or the overall conjecture of consciousness that stands alone as to an everlasting vanquishment into the ever unchangeless state of unconsciousness, and its abysses is only held by its incestuousness.
EVOLVING PRINCIPLES OF THOUGHT
                               
BOOK FOUR
SYSTEMATIC DELINEATION
Finding to a theory that magnifies the role of decisions, or free selection from among equally possible alternatives, in order to show that what appears to be objective or fixed by nature is in fact an artefact of human convention, similar to conventions of etiquette, or grammar, or law. Thus one might suppose that moral rules owe more to social convention than to anything imposed from outside, or have  supposedly inexorable necessities are in fact the shadow of our linguistic conventions. The disadvantage of conventionalism is that it must show that alternative, equally workable conventions could have been adopted, and it is often easy to believe that, for example, if we hold that some ethical norm such as respect for promises or property is conventional, we ought to be able to show that human needs would have been equally well satisfied by a system involving a different norm, and this may be hard to establish.
 A convention also suggested by Paul Grice (1913-88) directing participants in conversation to pay heed to an accepted purpose or direction of the exchange. Contributions made without paying this attention are liable to be rejected for other reasons than straightforward falsity: Something rue but unhelpful or inappropriate may meet with puzzlement or rejection. We can nevertheless, infer from the fact that it would be inappropriate to say something in some circumstance that what would be aid, were we to say it, would be false. This inference was frequently and in ordinary language philosophy, it being argued, for example, that since we do not normally say ‘there sees to be a barn there’ when there is unmistakably a barn there, it is false that on such occasions there seems to be a barn there.
 There are two main views on the nature of theories. According to the ‘received view’ theories are partially interpreted axiomatic systems, according to the semantic view, a theory is a collection of models (Suppe, 1974). However, a natural language comes ready interpreted, and the semantic problem is no that of the specification but of understanding the relationship between terms of various categories (names, descriptions, predicates, adverbs . . .) and their meanings. An influential proposal is that this relationship is best understood by attempting to provide a ‘truth definition’ for the language, which will involve giving terms and structure of different kinds have on the truth-condition of sentences containing them.
 The axiomatic method . . . as, . . . a proposition lid down as one from which we may begin, an assertion that we have taken as fundamental, at least for the branch of enquiry in hand. The axiomatic method is that of defining as a set of such propositions, and the ‘proof procedures’ or finding of how a proof ever gets started. Suppose I have as premises (1) p and (2) p ➞ q. Can I infer q? Only, it seems, if I am sure of, (3) (p & p ➞q) ➞q. Can I then infer q? Only, it seems, if I am sure that (4) (p & p ➞ q) ➞ q) ➞ q. For each new axiom (N) needing a further axiom (N + 1) telling me that the set so far implies q, and the regress never stops. The usual solution is to treat a system as containing not only axioms, but also rules of reference, allowing movement fro the axiom. The rule ‘modus ponens’ allow us to pass from the first two premises to 'q'. Charles Dodgson Lutwidge (1832-98) better known as Lewis Carroll’s puzzle shows that it is essential to distinguish two theoretical categories, although there may be choice about which to put in which category.
 This type of theory (axiomatic) usually emerges as a body of (supposes) truths that are not nearly organized, making the theory difficult to survey or study a whole. The axiomatic method is an idea for organizing a theory (Hilbert 1970): one tries to select from among the supposed truths a small number from which all others can be seen to be deductively inferable. This makes the theory rather more tractable since, in a sense, all the truths are contained in those few. In a theory so organized, the few truths from which all others are deductively inferred are called axioms. In that, just as algebraic and differential equations, which were used to study mathematical and physical processes, could they be made mathematical objects, so axiomatic theories, like algebraic and differential equations, which are means of representing physical processes and mathematical structures, could be made objects of mathematical investigation.
 In the traditional (as in Leibniz, 1704), many philosophers had the conviction that all truths, or all truths about a particular domain, followed from a few principles. These principles were taken to be either metaphysically prior or epistemologically prior or in the fist sense, they were taken to be entities of such a nature that what exists is ‘caused’ by them. When the principles were taken as epistemologically prior, that is, as axioms, they were taken to be epistemologically privileged either, e.g., self-evident, not needing to be demonstrated or (again, inclusive ‘or’) to be such that all truths do follow from them (by deductive inferences). Gödel (1984) showed that treating axiomatic theories as themselves mathematical objects, that mathematics, and even a small part of mathematics, elementary number theory, could not be axiomatized, that, more precisely, any class of axioms that in such that we could effectively decide, of any proposition, whether or not it was in the class, would be too small to capture all of the truths.
 The use of a model to test for the consistency of an axiomatized system is older than modern logic. Descartes’s algebraic interpretation of Euclidean geometry provides a way of showing that if the theory of real numbers is consistent, so is the geometry. Similar mapping had been used by mathematicians in the 19th century for example to show that if Euclidean geometry is consistent, so are various non-Euclidean geometries. Model theory is the general study of this kind of procedure: The study of interpretations of formal system. Proof theory studies relations of deductibility as defined purely syntactically, that is, without reference to the intended interpretation of the calculus. More formally, a deductively valid argument starting from true premises, that yields the conclusion between formulae of a system. But once the notion of an interpretation is in place we can ask whether a formal system meets certain conditions. In particular, can it lead us from sentences that are true under some interpretation to ones that are false under the same interpretation? And if a sentence is true under all interpretations, is it also a theorem of the system? We can define a notion of validity (a formula is valid if it is true in all interpretations) and semantic consequence, its formula is written as,
{A1 . . . An} ⊨ B
if it is true in all interpretations in which they are true) The central questions for a calculus will be whether all and only its theorems are valid, and whether {A1 . . . An} ⊨ B, if and only if {A1. . . . An} ⊢ B. These are the questions of the soundness and completeness of a formal system. For the propositional calculus this turns into the question of whether the proof theory delivers as theorems all and only tautologies. There are many axiomatizations of the propositional calculus that are consistent an complete. Gödel proved in 1929 that first-order predicate calculus is complete: any formula that is true under every interpretation is a theorem of the calculus.
 The propositional calculus or logical calculus whose expressions are character representation sentences or propositions, and constants representing operations on those propositions to produce others of higher complexity. The operations include conjunction, disjunction, material implication and negation (although these need not be primitive). Propositional logic was partially anticipated by the Stoics but researched maturity only with the work of Frége, Russell, and Wittgenstein.
 The concept introduced by Frége of a function taking a number of names as arguments, and delivering one proposition as the value. The idea is that ‘χ love’s y’ is a propositional function, which yields the proposition ‘John loves Mary’ from those two arguments (in that order). A propositional function is therefore roughly equivalent to a property or relation. In Principia Mathematica, Russell and Whitehead take propositional functions to be the fundamental function, since the theory of descriptions could be taken as showing that other expressions denoting functions are incomplete symbols.
 Keeping in mind, the two classical truth-values that a statement, proposition, or sentence can take. It is supposed in classical (two-valued) logic, that each statement has one of these values, and none has both. A statement is then false if and only if it is not true. The basis of this scheme is that to each statement there corresponds a determinate truth condition, or way the world must be for it to be true, and otherwise false. Statements may be felicitous or infelicitous in other dimensions (polite, misleading, apposite, witty, etc.) but truth is the central normative governing assertion. Considerations of vagueness may introduce greys into a black-and-white scheme. For the issue of whether falsity is the only way of failing to be true.
 Formally, it is nonetheless, that any suppressed premise or background framework of thought necessary to make an argument valid, or a position tenable. More formally, a presupposition has been defined as a proposition whose truth is necessary for either the truth or the falsity of another statement. Thus, if ‘p’ presupposes ‘q’, ‘q’ must be true for p to be either true or false. In the theory of knowledge of Robin George Collingwood (1889-1943), any propositions capable of truth or falsity stand on a bed of ‘absolute presuppositions’ which are not properly capable of truth or falsity, since a system of thought will contain no way of approaching such a question. It was suggested by Peter Strawson (1919-), in opposition to Russell’s theory of ‘definite’ descriptions, that ‘there exists a King of France’ is a presupposition of ‘the King of France is bald’, the latter being neither true, nor false, if there is no King of France. It is, however, a little unclear whether the idea is that no statement at all is made in such a case, or whether a statement i can made, but fails of being one a true and oppose of either true ids false. The former option preserves classical logic, since we can still say that every statement is either true or false, but the latter does not, since in classical logic the law of ‘bivalence’ holds, and ensures that nothing at all is presupposed for any proposition to be true or false. The introduction of presupposition therefore means that either a third truth-value is found, ‘intermediate’ between truth and falsity, or classical logic is preserved, but it is impossible to tell whether a particular sentence expresses a proposition that is a candidate for truth ad falsity, without knowing more than the formation rules of the language. Each suggestion carries costs, and there is some consensus that at least where definite descriptions are involved, examples like the one given are equally well handed by regarding the overall sentence false when the existence claim fails.
 A proposition may be true or false it is said to take the truth-value true, and if the latter the truth-value false. The idea behind the term is the analogy between assigning a propositional variable one or other of these values, as a formula of the propositional calculus, and assigning an object as the value of many other variable. Logics with intermediate values are called many-valued logics. Then, a truth-function of a number of propositions or sentences is a function of them that has a definite truth-value, depends only on the truth-values of the constituents. Thus (p & q) is a combination whose truth-value is true when ‘p’ is true and ‘q’ is true, and false otherwise, ¬ p is a truth-function of ‘p’, false when ‘p’ is true and true when ‘p’ is false. The way in which the value of the whole is determined by the combinations of values of constituents is presented in a truth table.
 In whatever manner, truths of fact cannot be reduced to any identity and our only way of knowing them is a posteriori, by reference to the facts of the empirical world.
 A proposition is knowable a priori if it can be known without experience of the specific course of events in the actual world. It may, however, be allowed that some experience is required to acquire the concepts involved in an a priori proposition. Some thing is knowable only a posteriori if it can be known a priori. The distinction given one of the fundamental problem areas of epistemology. The category of a priori propositions is highly controversial, since it is not clear how pure thought, unaided by experience, can give rise to any knowledge at all, and it has always been a concern of empiricism to deny that it can. The two great areas in which it seems to be so are logic and mathematics, so empiricists have commonly tried to show either that these are not areas of real, substantive knowledge, or that in spite of appearances their knowledge that we have in these areas is actually dependent on experience. The former line tries to show sense trivial or analytic, or matters of notation conventions of language. The latter approach is particularly y associated with Quine, who denies any significant slit between propositions traditionally thought of as a priori, and other deeply entrenched beliefs that occur in our overall view of the world.
 Another contested category is that of a priori concepts, supposed to be concepts that cannot be ‘derived’ from experience, but which are presupposed in any mode of thought about the world, time, substance, causation, number, and self are candidates. The need for such concept s, and the nature of the substantive a prior  knowledge to which they give rise, is the central concern of Kant ‘s Critique of Pure Reason.
 Likewise, since their denial does not involve a contradiction, there is merely contingent: Their could have been in other ways a hold of the actual world, but not every possible one. Some examples are ‘Caesar crossed the Rubicon’ and ‘Leibniz was born in Leipzig’, as well as propositions expressing correct scientific generalizations. In Leibniz’s view truths of fact rest on the principle of sufficient reason, which is a reason why it is so. This reason is that the actual world (by which he means the total collection of things past, present and future) is better than any other possible world and therefore created by God. The foundation of his thought is the conviction that to each individual there corresponds a complete notion, knowable only to God, from which is deducible all the properties possessed by the individual at each moment in its history. It is contingent that God actualizes te individual that meets such a concept, but his doing so is explicable by the principle of ‘sufficient reason’, whereby God had to actualize just that possibility in order for this to be the best of all possible worlds. This thesis is subsequently lampooned by Voltaire (1694-1778), in whom of which was prepared to take refuge in ignorance, as the nature of the soul, or the way to reconcile evil with divine providence.
 In defending the principle of sufficient reason sometimes described as the principle that nothing can be so without there being a reason why it is so. But the reason has to be of a particularly potent kind: eventually it has to ground contingent facts in necessities, and in particular in the reason an omnipotent and perfect being would have for actualizing one possibility than another. Among the consequences of the principle is Leibniz’s relational doctrine of space, since if space were an infinite box there could be no reason for the world to be at one point in rather than another, and God placing it at any point violate the principle. In Abelard’s (1079-1142), as in Leibniz, the principle eventually forces te recognition that the actual world is the best of all possibilities, since anything else would be inconsistent with the creative power that actualizes possibilities.
 If truth consists in concept containment, then it seems that all truths are analytic and hence necessary; and if they are all necessary, surely they are all truths of reason. In that not every truth can be reduced to an identity in a finite number of steps; in some instances revealing the connection between subject and predicate concepts would require an infinite analysis, while this may entail that we cannot prove such proposition as a prior, it does not appear to show that proposition could have been false. Intuitively, it seems a better ground for supposing that it is a necessary truth of a special sort. A related question arises from the idea that truths of fact depend on God’s decision to create the best world: If it is part of the concept of this world that it is best, how could its existence be other than necessary? An accountable and responsively answered explanation would be so, that any relational question that brakes the norm lay eyes on its existence in the manner other than hypothetical necessities, i.e., it follows from God’s decision to create the world, but God had the power to create this world, but God is necessary, so how could he have decided to do anything else? Leibniz says much more about these matters, but it is not clear whether he offers any satisfactory solutions.
 The view that the terms in which we think of some area are sufficiently infected with error for it to be better to abandon them than to continue to try to give coherent theories of their use. Eliminativism should be distinguished from scepticism that claims that we cannot know the truth about some area; eliminativism claims rather that there are no truth there to be known, in the terms that we currently think. An eliminativist about theology simply counsels abandoning the terms or discourse of theology, and that will include abandoning worries about the extent of theological knowledge.
 Eliminativists in the philosophy of mind counsel abandoning the whole network of terms mind, consciousness, self, qualia that usher in the problems of mind and body. Sometimes the argument for doing this is that we should wait for a supposed future understanding of ourselves, based on cognitive science and better than any our current mental descriptions provide, sometimes it is supposed that physicalism shows that no mental description of ourselves could possibly be true.
 Greek scepticism centred on the value of enquiry and questioning, scepticism is now the denial that knowledge or even rational belief is possible, either about some specific subject-matter, e.g., ethics, o r in any atra whatsoever. Classically, scepticism springs from the observation that the best methods in some area seem to fall short of giving us contact with the truth, e.g., there is a gulf between appearance and reality, and in frequency cites the conflicting judgements that our methods deliver, with the result that questions of truth become undecidable.
 Sceptical tendencies emerged in the 14th-century writings of Nicholas of Autrecourt. His criticisms of any certainty beyond the immediate deliverance of the senses and basic logic, and in particular of any knowledge of either intellectual or material substances, anticipate the later scepticism of Balye and Hume. The; later distinguishes between Pyrrhonistic and excessive scepticism, which he regarded as unlivable, and the more mitigated scepticism that accepts every day or commonsense beliefs (not as the delivery of reason, but as due more to custom and habit), but is duly wary of the power of reason to give us much more. Mitigated scepticism is thus closer to the attitude fostered by ancient scepticism from Pyrrho through to Sexus Empiricus. Although the phrase ‘Cartesian scepticism’ is sometimes used, Descartes himself was not a sceptic, but in the method of doubt, uses a sceptical scenario in order to begin the process of finding a secure mark of knowledge. Descartes himself trusts a category of ‘clear and distinct’ ideas, not far removed from the phantasia kataleptiké of the Stoics.
 Scepticism should not be confused with relativism, which is a doctrine about the nature of truth, and may be motivated by trying to avoid scepticism. Nor is it identical with eliminativism, which counsels abandoning an area of thought altogether, not because we cannot know the truth, but because there are no truths capable of being framed in the terms we use.
 Descartes’s theory of knowledge starts with the quest for certainty, for an indubitable starting-point or foundation on the basis alone of which progress is possible. This is eventually found in the celebrated ‘Cogito ergo sum’: I think therefore I am. By locating the point of certainty in my own awareness of my own self, Descartes gives a first-person twist to the theory of knowledge that dominated them following centuries in spite of various counter-attacks on behalf of social and public starting-points. The metaphysical associated with this priority are the famous Cartesian dualism, or separation of mind and matter into two different but interacting substances, Descartes rigorously and rightly sees that it takes divine dispensation to certify any relationship between the two realms thus divided, and to prove the reliability of the senses invokes a ‘clear and distinct perception’ of highly dubious proofs of the existence of a benevolent deity. This has not met general acceptance: as Hume drily puts it, ‘to have recourse to the veracity of the supreme Being, in order to prove the veracity of our senses, is surely making a very unexpected circuit’.
 In his own time Descartes’s conception of the entirely separate substance of the mind was recognized to give rise to insoluble problems of the nature of the causal connection between the two. It also gives rise to the problem, insoluble in its own terms, of other minds. Descartes’s notorious denial that non-human animals are conscious is a stark illustration of the problem. In his conception of matter Descartes also gives preference to rational cogitation over anything derived from the senses. Since we can conceive of the matter of a ball of wax surviving changes to its sensible qualities, matter is not an empirical concept, but eventually an entirely geometrical one, with extension and motion as its only physical nature. Descartes’s thought, as reflected in Leibniz, that the qualities of sense experience have no resemblance to qualities of things, so that knowledge of the external world is essentially knowledge of structure rather than of filling. On this basis Descartes erects a remarkable physics. Since matter is in effect the same as extension there can be no empty space or ‘void’, since there is no empty space motion is not a question of occupying previously empty space, but is to be thought of in terms of vortices (like the motion of a liquid).
 Although the structure of Descartes’s epistemology, theories of mind, and theory of matter have been rejected many times, their relentless exposure of the hardest issues, their exemplary clarity, and even their initial plausibility, all contrives to make him the central point of reference for modern philosophy.
 The self conceived as Descartes presents it in the first two Meditations: aware only of its own thoughts, and capable of disembodied existence, neither situated in a space nor surrounded by others. This is the pure self of ‘I-ness’ that we are tempted to imagine as a simple unique thing that make up our essential identity. Descartes’s view that he could keep hold of this nugget while doubting everything else is criticized by Lichtenberg and Kant, and most subsequent philosophers of mind.
 Descartes holds that we do not have any knowledge of any empirical proposition about anything beyond the contents of our own minds. The reason, roughly put, is that there is a legitimate doubt about all such propositions because there is no way to deny justifiably that our senses are being stimulated by some cause (an evil spirit, for example) which is radically different from the objects that we normally think affect our senses.
 He also points out, that the senses (sight, hearing, touch, etc., are often unreliable, and ‘it is prudent never to trust entirely those who have deceived us even once’, he cited such instances as the straight stick that looks ben t in water, and the square tower that look round from a distance. This argument of illusion, has not, on the whole, impressed commentators, and some of Descartes’ contemporaries pointing out that since such errors come to light as a result of further sensory information, it cannot be right to cast wholesale doubt on the evidence of the senses. But Descartes regarded the argument from illusion as only the first stage in softening up process which would ‘lead the mind away from the senses’. He admits that there are some cases of sense-base  belief about which doubt would be insane, e.g., the belief that I am sitting here by the fire, wearing a winter dressing gown’.
 Descartes was to realize that there was nothing in this view of nature that could explain or provide a foundation for the mental, or from direct experience as distinctly human. In a mechanistic universe, he said, there is no privileged place or function for mind, and the separation between mind and matter is absolute. Descartes was also convinced, that the immaterial essences that gave form and structure to this universe were coded in geometrical and mathematical ideas, and this insight led him to invent algebraic geometry.
 A scientific understanding of these ideas could be derived, said Descartes, with the aid of precise deduction, and he also claimed that the contours of physical reality could be laid out in three-dimensional coordinates. Following the publication of Newton’s Principia Mathematica in 1687, reductionism and mathematical modelling became the most powerful tools of modern science. And the dream that the entire physical world could be known and mastered through the extension and refinement of mathematical theory became the central feature and guiding principle of scientific knowledge.
 Having to its  recourse of knowledge, its cental questions include the origin of knowledge, the place of experience in generating knowledge, and the place of reason in doing so, the relationship between knowledge and certainty, and between knowledge and the impossibility of error, the possibility of universal scepticism, and the changing forms of knowledge that arise from new conceptualizations of the world. All of these issues link with other central concerns of philosophy, such as the nature of truth and the natures of experience and meaning.
 Foundationalism was associated with the ancient Stoics, and in the modern era with Descartes (1596-1650). Who discovered his foundations in the ‘clear and distinct’ ideas of reason? Its main opponent is Coherentism, or the view that a body of propositions mas be known without a foundation in certainty, but by their interlocking strength, than as a crossword puzzle may be known to have been solved correctly even if each answer, taken individually, admits of uncertainty. Difficulties at this point led the logical passivists to abandon the notion of an epistemological foundation altogether, and to flirt with the coherence theory of truth. It is widely accepted that trying to make the connection between thought and experience through basic sentences depends on an untenable ‘myth of the given’.
 Still in spite of these concerns, the problem, least of mention, is of defining knowledge in terms of true beliefs plus some favoured relations between the believer and the facts that began with Plato’s view in the “Theaetetus,” that knowledge is true belief, and some logos. Due of its nonsynthetic epistemology, the enterprising of studying the actual formation of knowledge by human beings, without aspiring to certify those processes as rational, or its proof against ‘scepticism’ or even apt to yield the truth. Natural epistemology would therefore blend into the psychology of learning and the study of episodes in the history of science. The scope for ‘external’ or philosophical reflection of the kind that might result in scepticism or its refutation is markedly diminished. Despite the fact that the terms of modernity are so distinguished as exponents of the approach include Aristotle, Hume, and J. S. Mills.
 The task of the philosopher of a discipline would then be to reveal the correct method and to unmask counterfeits. Although this belief lay behind much positivist philosophy of science, few philosophers now subscribe to it. It places too well a confidence in the possibility of a purely previous ‘first philosophy’, or viewpoint beyond that of the work one’s way of practitioners, from which their best efforts can be measured as good or bad. These standpoints now seem that too many philosophers to be a fanciefancy, that the more modest of tasks that are actually adopted at various historical stages of investigation into different areas with the aim not so much of criticizing but more of systematization, in the presuppositions of a particular field at a particular tie. There is still a role for local methodological disputes within the community  investigators of some phenomenon, with one approach charging that another is unsound or unscientific, but logic and philosophy will not, on the modern view, provide an independent arsenal of weapons for such battles, which indeed often come to seem more like political bids for ascendancy within a discipline.
 This is an approach to the theory of knowledge that sees an important connection between the growth of knowledge and biological evolution. An evolutionary epistemologist claims that the development of human knowledge processed through some natural selection process, the best example of which is Darwin’s theory of biological natural selection. There is a widespread misconception that evolution proceeds according to some plan or direct, but it has neither, and the role of chance ensures that its future course will be unpredictable. Random variations in individual organisms create tiny differences in their Darwinian fitness. Some individuals have more offsprings than others, and the characteristics that increased their fitness thereby become more prevalent in future generations. Once upon a time, at least a mutation occurred in a human population in tropical Africa that changed the haemoglobin molecule in a way that provided resistance to malaria. This enormous advantage caused the new gene to spread, with the unfortunate consequence that sickle-cell anaemia came to exist.
 Chance can influence the outcome at each stage: First, in the creation of genetic mutation, second, in wether the bearer lives long enough to show its effects, thirdly, in chance events that influence the individual’s actual reproductive success, and fourth, in whether a gene even if favoured in one generation, is, happenstance, eliminated in the next, and finally in the many unpredictable environmental changes that will undoubtedly occur in the history of any group of organisms. As Harvard biologist Stephen Jay Gould has so vividly expressed that process over again, the outcome would surely be different. Not only might there not be humans, there might not even be anything like mammals.
 We will often emphasis the elegance of traits shaped by natural selection, but the common idea that nature creates perfection needs to be analysed carefully. The extent to which evolution achieves perfection depends on exactly what you mean. If you mean “Does natural selections always take the best path for the long-term welfare of a species?” The answer is no. That would require adaption by group selection, and this is, unlikely. If you mean “Does natural selection creates every adaption that would be valuable?” The answer again, is no. For instance, some kinds of South American monkeys can grasp branches with their tails. The trick would surely also be useful to some African species, but, simply because of bad luck, none have it. Some combination of circumstances started some ancestral South American monkeys using their tails in ways that ultimately led to an ability to grab onto branches, while no such development took place in Africa. Mere usefulness of a trait does not necessitate a means in that what will understandably endure phylogenesis or evolution.
 This is an approach to the theory of knowledge that sees an important connection between the growth of knowledge and biological evolution. An evolutionary epistemologist claims that the development of human knowledge proceeds through some natural selection process, the best example of which is Darwin’s theory of biological natural selection.  The three major components of the model of natural selection are variation selection and retention. According to Darwin’s theory of natural selection, variations are not pre-designed to do certain functions. Rather, these variations that do useful functions are selected. While those that do not employ of some coordinates in that are regainfully purposed are also, not to any of a selection, as duly influenced of such a selection, that may have responsibilities for the visual aspects of a variational intentionally occurs. In the modern theory of evolution, genetic mutations provide the blind variations: Blind in the sense that variations are not influenced by the effects they would have-the likelihood of a mutation is not correlated with the benefits or liabilities that mutation would confer on the organism, the environment provides the filter of selection, and reproduction provides the retention. Fatnesses are achieved because those organisms with features that make them less adapted for survival do not survive in connection with other organisms in the environment that have features that are better adapted. Evolutionary epistemology applies this blind variation and selective retention model to the growth of scientific knowledge and to human thought processes overall.
 The parallel between biological evolution and conceptual or ‘epistemic’ evolution can be seen as either literal or analogical. The literal version of evolutionary epistemology deeds biological evolution as the main cause of the growth of knowledge. On this view, called the ‘evolution of cognitive mechanic programs’, by Bradie (1986) and the ‘Darwinian approach to epistemology’ by Ruse (1986), that growth of knowledge occurs through blind variation and selective retention because biological natural selection itself is the cause of epistemic variation and selection. The most plausible version of the literal view does not hold that all human beliefs are innate but rather than the mental mechanisms that guide the acquisitions of non-innate beliefs are themselves innately and the result of biological natural selection. Ruse, (1986) demands of a version of literal evolutionary epistemology that he links to sociolology (Rescher, 1990).
 On the analogical version of evolutionary epistemology, called the ‘evolution of theory’s program’, by Bradie (1986). The ‘Spenserians approach’ (after the nineteenth century philosopher Herbert Spencer) by Ruse (1986), the development of human knowledge is governed by a process analogous to biological natural selection, rather than by an instance of the mechanism itself. This version of evolutionary epistemology, introduced and elaborated by Donald Campbell (1974) as well as Karl Popper, sees the [partial] fit between theories and the world as explained by a mental process of trial and error known as epistemic natural selection.
 Both versions of evolutionary epistemology are usually taken to be types of naturalized epistemology, because both take some empirical facts as a starting point for their epistemological project. The literal version of evolutionary epistemology begins by accepting evolutionary theory and a materialist approach to the mind and, from these, constructs an account of knowledge and its developments. In contrast, the metaphorical version does not require the truth of biological evolution: It simply draws on biological evolution as a source for the model of natural selection. For this version of evolutionary epistemology to be true, the model of natural selection need only apply to the growth of knowledge, not to the origin and development of species. Crudely put, evolutionary epistemology of the analogical sort could still be true even if Creationism is the correct theory of the origin of species.
 Although they do not begin by assuming evolutionary theory, most analogical evolutionary epistemologists are naturalized epistemologists as well, their empirical assumptions, least of mention, implicitly come from psychology and cognitive science, not evolutionary theory. Sometimes, however, evolutionary epistemology is characterized in a seemingly non-naturalistic fashion. Campbell (1974) says that ‘if one is expanding knowledge beyond what one knows, one has no choice but to explore without the benefit of wisdom’, i.e., blindly. This, Campbell admits, makes evolutionary epistemology close to being a tautology (and so not naturalistic). Evolutionary epistemology does assert the analytic claim that when expanding one’s knowledge beyond what one knows, one must precessed to something that is already known, but, more interestingly, it also makes the synthetic claim that when expanding one’s knowledge beyond what one knows, one must proceed by blind variation and selective retention. This claim is synthetic because it can be empirically falsified. The central claim of evolutionary epistemology is synthetic, not analytic. If the central contradictory, which they are not. Campbell is right that evolutionary epistemology does have the analytic feature he mentions, but he is wrong to think that this is a distinguishing feature, since any plausible epistemology has the same analytic feature (Skagestad, 1978).
 Two extraordinary issues lie to awaken the literature that involves questions about ‘realism’, i.e., What metaphysical commitment does an evolutionary epistemologist have to make? Progress, i.e., according to evolutionary epistemology, does knowledge develop toward a goal? With respect to realism, many evolutionary epistemologists endorse that is called ‘hypothetical realism’, a view that combines a version of epistemological ‘scepticism’ and tentative acceptance of metaphysical realism. With respect to progress, the problem is that biological evolution is not goal-directed, but the growth of human knowledge seems to be. Campbell (1974) worries about the potential dis-analogy here but is willing to bite the stone of conscience and admit that epistemic evolution progress toward a goal (truth) while biologic evolution does not. Many another has argued that evolutionary epistemologists must give up the ‘truth-topic’ sense of progress because a natural selection model is in essence, is non-teleological, as an alternative, following Kuhn (1970), and embraced in the accompaniment with evolutionary epistemology.
 Among the most frequent and serious criticisms levelled against evolutionary epistemology is that the analogical version of the view is false because epistemic variation is not blind (Skagestad, 1978, 613-16, and Ruse, 1986, ch.2 (. Stein and Lipton (1990) have argued, however, that this objection fails because, while epistemic variation is not random, its constraints come from heuristics that, for the most part, are selective retention. Further, Stein and Lipton come to the conclusion that heuristics are analogous to biological pre-adaptions, evolutionary pre-biological pre-adaptions, evolutionary cursors, such as a half-wing, a precursor to a wing, which have some function other than the function of their descendable structures: The function of descendable structures, the function of their descendable character embodied to its structural foundations, is that of the guidelines of epistemic variation is, on this view, not the source of disanalogy, but the source of a more articulated account of the analology.
 Many evolutionary epistemologists try to combine the literal and the analogical versions (Bradie, 1986, and Stein and Lipton, 1990), saying that those beliefs and cognitive mechanisms, which are innate results from natural selection of the biological sort and those that are innate results from natural selection of the epistemic sort. This is reasonable as long as the two parts of this hybrid view are kept distinct. An analogical version of evolutionary epistemology with biological variation as its only source of blondeness would be a null theory: This would be the case if all our beliefs are innate or if our non-innate beliefs are not the result of blind variation. An appeal to the legitimate way to produce a hybrid version of evolutionary epistemology since doing so trivializes the theory. For similar reasons, such an appeal will not save an analogical version of evolutionary epistemology from arguments to the effect that epistemic variation is blind (Stein and Lipton, 1990).
 Although it is a new approach to theory of knowledge, evolutionary epistemology has attracted much attention, primarily because it represents a serious attempt to flesh out a naturalized epistemology by drawing on several disciplines. In science is relevant to understanding the nature and development of knowledge, then evolutionary theory is among the disciplines worth a look. Insofar as evolutionary epistemology looks there, it is an interesting and potentially fruitful epistemological programme.
 What makes a belief justified and what makes a true belief knowledge? Thinking that whether a belief deserves one of these appraisals is natural depends on what caused the depicted branch of knowledge to have the belief. In recent decades a number of epistemologists have pursued this plausible idea with a variety of specific proposals. Some causal theories of knowledge have it that a true belief that ‘p’ is knowledge just in case it has the right causal connection to the fact that ‘p’. Such a criterion can be applied only to cases where the fact that ‘p’ is a sort that can enter into causal relations, as this seems to exclude mathematically and the necessary facts and perhaps any fact expressed by a universal generalization, and proponents of this sort of criterion have usually supposed that it is limited to perceptual representations where knowledge of particular facts about subjects’ environments.
 For example, Armstrong (1973), predetermined that a  position held by a belief in the form ‘This perceived object is ‘F’ is [non-inferential] knowledge if and only if the belief is a completely reliable sign that the perceived object is ‘F’, that is, the fact that the object is ‘F’ contributed to causing the belief and its doing so depended on properties of the believer such that the laws of nature dictated that, for any subject ‘χ’ and perceived object ‘y’, if ‘χ’ has those properties and believed that ‘y’ is ‘F’, then ‘y’ is ‘F’. (Dretske (1981) offers a rather similar account, in terms of the belief’s being caused by a signal received by the perceiver that carries the information that the object is ‘F’).
 Goldman (1986) has proposed an importantly different causal criterion, namely, that a true belief is knowledge if it is produced by a type of process that is ‘globally’ and ‘locally’ reliable. Causing true beliefs is sufficiently high is globally reliable if its propensity. Local reliability has to do with whether the process would have produced a similar but false belief in certain counterfactual situations alternative to the actual situation. This way of marking off true beliefs that are knowledge does not require the fact believed to be causally related to the belief, and so it could in principle apply to knowledge of any kind of truth.
 Goldman requires the global reliability of the belief-producing process for the justification of a belief, he requires it also for knowledge because justification is required for knowledge. What he requires for knowledge, but does not require for justification is local reliability. His idea is that a justified true belief is knowledge if the type of process that produced it would not have produced it in any relevant counterfactual situation in which it is false. Its purported theory of relevant alternatives can be viewed as an attempt to provide a more satisfactory response to this tension in our thinking about knowledge. It attempts to characterize knowledge in a way that preserves both our belief that knowledge is an absolute concept and our belief that we have knowledge.
 According to the theory, we need to qualify rather than deny the absolute character of knowledge. We should view knowledge as absolute, reactive to certain standards (Dretske, 1981 and Cohen, 1988). That is to say, in order to know a proposition, our evidence need not eliminate all the alternatives to that preposition, rather for ‘us’, that we can know our evidence eliminates al the relevant alternatives, where the set of relevant alternatives (a proper subset of the set of all alternatives) is determined by some standard. Moreover, according to the relevant alternatives view, and the standards determining that of the alternatives is raised by the sceptic are not relevant. If this is correct, then the fact that our evidence cannot eliminate the sceptic’s alternative does not lead to a sceptical result. For knowledge requires only the elimination of the relevant alternatives, so the relevant alternative view preserves in both strands in our thinking about knowledge. Knowledge is an absolute concept, but because the absoluteness is relative to a standard, we can know many things.
 The interesting thesis that counts as a causal theory of justification (in the meaning of ‘causal theory’ intended here) is that: A belief is justified in case it was produced by a type of process that is ‘globally’ reliable, that is, its propensity to produce true beliefs-that can be defined (to a good approximation) As the proportion of the beliefs it produces (or would produce) that is true  is sufficiently great.
 This proposal will be adequately specified only when we are told (i) how much of the causal history of a belief counts as part of the process that produced it, (ii) which of the many types to which the process belongs is the type for purposes of assessing its reliability, and (iii) relative to why the world or worlds are the reliability of the process type to be assessed  the actual world, the closet worlds containing the case being considered, or something else? Let ‘us’ look at the answers suggested by Goldman, the leading proponent of a reliabilist account of justification.
   (1) Goldman (1979, 1986) takes the relevant belief producing process to include only the proximate causes internal to the believer. So, for instance, when recently I believed that the telephone was ringing the process that produced the belief, for purposes of assessing reliability, includes just the causal chain of neural events from the stimulus in my ear’s inward ands other concurrent brain states on which the production of the belief depended: It does not include any events’ as the telephone, or the sound waves travelling between it and my ears, or any earlier decisions I made that were responsible for my being within hearing distance of the telephone at that time. It does seem intuitively plausible of a belief depends should be restricted to internal omnes proximate to the belief. Why? Goldman does not tell ‘us’. One answer that some philosophers might give is that it is because a belief’s being justified at a given time can depend only on facts directly accessible to the believer’s awareness at that time (for, if a believer ought to holds only beliefs that are justified, she can tell at any given time what beliefs would then be justified for her). However, this cannot be Goldman’s answer because he wishes to include in the relevantly process neural events that are not directly accessible to consciousness.
   (2) Once the reliabilist has told ‘us’ how to delimit the process producing a belief, he needs to tell ‘us’ which of the many types to which it belongs is the relevant type. Coincide, for example, the process that produces your current belief that you see a book before you. One very broad type to which that process belongs would be specified by ‘coming to a belief as to something one perceives as a result of activation of the nerve endings in some of one’s sense-organs’. A constricted type, in which that unvarying processes belong would be specified by ‘coming to a belief as to what one sees as a result of activation of the nerve endings in one’s retinas’. A still narrower type would be given by inserting in the last specification a description of a particular pattern of activation of the retina’s particular cells. Which of these or other types to which the token process belongs is the relevant type for determining whether the type of process that produced your belief is reliable?
 If we select a type that is too broad, as having the same degree of justification various beliefs that intuitively seem to have different degrees of justification. Thus the broadest type we specified for your belief that you see a book before you apply also to perceptual beliefs where the object seen is far away and seen only briefly is less justified. On the other hand, is we are allowed to select a type that is as narrow as we please, then we make it out that an obviously unjustified but true belief is produced by a reliable type of process. For example, suppose I see a blurred shape through the fog far in a field and unjustifiedly, but correctly, believe that it is a sheep: If we include enough details about my retinal image is specifying te type of the visual process that produced that belief, we can specify a type is likely to have only that one instanced and is therefore 100 percent reliable. Goldman conjectures (1986) that the relevant process type is ‘the narrowest type that is casually operative’. Presumably, a feature of the process producing beliefs were causally operatives in producing it just in case some alternative feature instead, but it would not have led to that belief. (We need to say ‘some’ here rather than ‘any’, because, for example, when I see an oak or pine tree, the particular ‘like-minded’ material bodies of my retinal image are casually clearly toward the operatives in producing my belief that what is seen as a tree, even though there are alternative shapes, for example, ‘pineish’ or ‘birchness’ ones, that would have produced the same belief.)
   (3) Should the justification of a belief in a hypothetical, non-actual example turn on the reliability of the belief-producing process in the possible world of the example? That leads to the implausible result in that in a world run by a Cartesian demon-a powerful being who causes the other inhabitants of the world to have rich and coherent sets of perceptual and memory impressions that are all illusory the perceptual and memory beliefs of the other inhabitants are all unjustified, for they are produced by processes that are, in that world, quite unreliable. If we say instead that it is the reliability of the processes in the actual world that matters, we get the equally undesired result that if the actual world is a demon world then our perceptual and memory beliefs are all unjustified.
 Goldman’s solution (1986) is that the reliability of the process types is to be gauged by their performance in ‘normal’ worlds, that is, worlds consistent with ‘our general beliefs about the world  . . . ‘about the sorts of objects, events and changes that occur in it’. This gives the intuitively right results for the problem cases just considered, but indicate by inference an implausible proportion of making compensations for alternative tending toward justification. If there are people whose general beliefs about the world are very different from mine, then there may, on this account, be beliefs that I can correctly regard as justified (ones produced by processes that are reliable in what I take to be a normal world) but that they can correctly regard as not justified.
 However, these questions about the specifics are dealt with, and there are reasons for questioning the basic idea that the criterion for a belief’s being justified is its being produced by a reliable process. Thus and so, doubt about the sufficiency of the reliabilist criterion is prompted by a sort of example that Goldman himself uses for another purpose. Suppose that being in brain-state ‘B’ always causes one to believe that one is in brained-state ‘B’. Here the reliability of the belief-producing process is perfect, but ‘we can readily imagine circumstances in which a person goes into grain-state ‘B’ and therefore has the belief in question, though this belief is by no means justified’ (Goldman, 1979). Doubt about the necessity of the condition arises from the possibility that one might know that one has strong justification for a certain belief and yet that knowledge is not what actually prompts one to believe. For example, I might be well aware that, having read the weather bureau’s forecast that it will be much hotter tomorrow. I have ample reason to be confident that it will be hotter tomorrow, but I irrationally refuse to believe it until Wally tells me that he feels in his joints that it will be hotter tomorrow. Here what prompts me to believe dors not justify my belief, but my belief is nevertheless justified by my knowledge of the weather bureau’s prediction and of its evidential force: I can advert to any disavowable inference that I ought not to be holding the belief. Indeed, given my justification and that there is nothing untoward about the weather bureau’s prediction, my belief, if true, can be counted knowledge. This sorts of example raises doubt whether any causal conditions, are it a reliable process or something else, is necessary for either justification or knowledge.
 Philosophers and scientists alike, have often held that the simplicity or parsimony of a theory is one reason, all else being equal, to view it as true. This goes beyond the unproblematic idea that simpler theories are easier to work with and gave greater aesthetic appeal.
 One theory is more parsimonious than another when it postulates fewer entities, processes, changes or explanatory principles: The simplicity of a theory depends on essentially the same consecrations, though parsimony and simplicity obviously become the same. Demanding clarification of what makes one theory simpler or more parsimonious is plausible than another before the justification of these methodological maxims can be addressed.
 If we set this description problem to one side, the major normative problem is as follows: What reason is there to think that simplicity is a sign of truth? Why should we accept a simpler theory instead of its more complex rivals? Newton and Leibniz thought that the answer was to be found in a substantive fact about nature. In “Principia,” Newton laid down as his first Rule of Reasoning in Philosophy that ‘nature does nothing in vain . . . ‘for Nature is pleased with simplicity and affects not the pomp of superfluous causes’. Leibniz hypothesized that the actual world obeys simple laws because God’s taste for simplicity influenced his decision about which world to actualize.
 The tragedy of the Western mind, described by Koyré, is a direct consequence of the stark Cartesian division between mind and world. We discovered the ‘certain principles of physical reality’, said Descartes, ‘not by the prejudices of the senses, but by the light of reason, and which thus possess so great evidence that we cannot doubt of their truth’. Since the real, or that which actually exists external to ourselves, was in his view only that which could be represented in the quantitative terms of mathematics, Descartes concludes that all quantitative aspects of reality could be traced to the deceitfulness of the senses.
 The most fundamental aspect of the Western intellectual tradition is the assumption that there is a fundamental division between the material and the immaterial world or between the realm of matter and the realm of pure mind or spirit. The metaphysical frame-work based on this assumption is known as ontological dualism.  As the word dual implies, the framework is predicated on an ontology, or a conception of the nature of God or Being, that assumes reality has two distinct and separable dimensions. The concept of Being as continuous, immutable, and having a prior or separate existence from the world of change dates from the ancient Greek philosopher Parmenides. The same qualities were associated with the God of the Judeo-Christian tradition, and they were considerably amplified by the role played in theology by Platonic and Neoplatonic philosophy.
 Nicolas Copernicus, Galileo, Johannes Kepler, and Isaac Newton were all inheritors of a cultural tradition in which ontological dualism was a primary article of faith. Hence the idealization of the mathematical ideal as a source of communion with God, which dates from Pythagoras, provided a metaphysical foundation for the emerging natural sciences. This explains why, the creators of classical physics believed that doing physics was a form of communion with the geometrical and mathematical form’s resident in the perfect mind of God. This view would survive in a modified form in what is now known as Einsteinian epistemology and accounts in no small part for the reluctance of many physicists to accept the epistemology associated with the Copenhagen Interpretation.
 At the beginning of the nineteenth century, Pierre-Sinon LaPlace, along with a number of other French mathematicians, advanced the view that the science of mechanics constituted a complete view of nature. Since this science, by observing its epistemology, had revealed itself to be the fundamental science, the hypothesis of God was, they concluded, entirely unnecessary.
 LaPlace is recognized for eliminating not only the theological component of classical physics but the ‘entire metaphysical component’ as well’. The epistemology of science requires, he said, that we proceed by inductive generalizations from observed facts to hypotheses that are ‘tested by observed conformity of the phenomena’. What was unique about LaPlace’s view of hypotheses was his insistence that we cannot attribute reality to them. Although concepts like force, mass, motion, cause, and laws are obviously present in classical physics, they exist in LaPlace’s view only as quantities. Physics is concerned, he argued, with quantities that we associate as a matter of convenience with concepts, and the truths about nature are only the quantities.
 As this view of hypotheses and the truths of nature as quantities were extended in the nineteenth century to a mathematical description of phenomena like heat, light, electricity, and magnetism. LaPlace’s assumptions about the actual character of scientific truths seemed correct. This progress suggested that if we could remove all thoughts about the ‘nature of’ or the ‘source of’ phenomena, the pursuit of strictly quantitative concepts would bring us to a complete description of all aspects of physical reality. Subsequently, figures like Comte, Kirchhoff, Hertz, and Poincaré developed a program for the study of nature hat was quite different from that of the original creators of classical physics.
 The seventeenth-century view of physics as a philosophy of nature or as natural philosophy was displaced by the view of physics as an autonomous science that was ‘the science of nature’. This view, which was premised on the doctrine of positivism, promised to subsume all of the nature with a mathematical analysis of entities in motion and claimed that the true understanding of nature was revealed only in the mathematical description. Since the doctrine of positivism assumes that the knowledge we call physics resides only in the mathematical formalism of physical theory, it disallows the prospect that the vision of physical reality revealed in physical theory can have any other meaning. In the history of science, the irony is that positivism, which was intended to banish metaphysical concerns from the domain of science, served to perpetuate a seventeenth-century metaphysical assumption about the relationship between physical reality and physical theory.
 Epistemology since Hume and Kant has drawn back from this theological underpinning. Indeed, the very idea that nature is simple (or uniform) has come in for a critique. The view has taken hold that a preference for simple and parsimonious hypotheses is purely methodological: It is constitutive of the attitude we call ‘scientific’ and makes no substantive assumption about the way the world is.
 A variety of otherwise diverse twentieth-century philosophers of science have attempted, in different ways, to flesh out this position. Two examples must suffice here: Hesse (1969) as, for summaries of other proposals. Popper (1959) holds that scientists should prefer highly falsifiable (improbable) theories: He tries to show that simpler theories are more falsifiable, also Quine (1966), in contrast, sees a virtue in theories that are highly probable, he argues for a general connection between simplicity and high probability.
 Both these proposals are global. They attempt to explain why simplicity should be part of the scientific method in a way that spans all scientific subject matters. No assumption about the details of any particular scientific problem serves as a premiss in Popper’s or Quine’s arguments.
 Newton and Leibniz thought that the justification of parsimony and simplicity flows from the hand of God: Popper and Quine try to justify these methodologically median of importance is without assuming anything substantive about the way the world is. In spite of these differences in approach, they have something in common. They assume that all users of parsimony and simplicity in the separate sciences can be encompassed in a single justifying argument. That recent developments in confirmation theory suggest that this assumption should be scrutinized. Good (1983) and Rosenkrantz (1977) has emphasized the role of auxiliary assumptions in mediating the connection between hypotheses and observations. Whether a hypothesis is well supported by some observations, or whether one hypothesis is better supported than another by those observations, crucially depends on empirical background assumptions about the inference problem here. The same view applies to the idea of prior probability (or, prior plausibility). In of a single hypo-physical science if chosen as an alternative to another even though they are equally supported by current observations, this must be due to an empirical background assumption.
 Principles of parsimony and simplicity mediate the epistemic connection between hypotheses and observations. Perhaps these principles are able to do this because they are surrogates for an empirical background theory. It is not that there is one background theory presupposed by every appeal to parsimony; This has the quantifier order backwards. Rather, the suggestion is that each parsimony argument is justified only to each degree that it reflects an empirical background theory about the subjective matter. On this theory is brought out into the open, but the principle of parsimony is entirely dispensable (Sober, 1988).
 This ‘local’ approach to the principles of parsimony and simplicity resurrects the idea that they make sense only if the world is one way rather than another. It rejects the idea that these maxims are purely methodological. How defensible this point of view is, will depend on detailed case studies of scientific hypothesis evaluation and on further developments in the theory of scientific inference.
 It is usually not found of one and the same that, an inference is a (perhaps very complex) act of thought by virtue of which act (1) I pass from a set of one or more propositions or statements to a proposition or statement and (2) it appears that the latter are true if the former is or are. This psychological characterization has occurred over a wider summation of literature under more lesser than inessential variations. Desiring a better characterization of inference is natural. Yet attempts to do so by constructing a fuller psychological explanation fail to comprehend the grounds on which inference will be objectively valid-A point elaborately made by Gottlob Frége. Attempts to understand the nature of inference through the device of the representation of inference by formal-logical calculations or derivations better (1) leave ‘us’ puzzled about the relation of formal-logical derivations to the informal inferences they are supposedly to represent or reconstruct, and (2) leaves ‘us’ worried about the sense of such formal derivations. Are these derivations inference? Are not informal inferences needed in order to apply the rules governing the constructions of formal derivations (inferring that this operation is an application of that formal rule)? These are concerns cultivated by, for example, Wittgenstein.
 Coming up with an adequate characterization of inference-and even working out what would count as a very adequate characterization here  is demandingly by no means nearly some resolved philosophical problem.
 The rule of inference, as for raised by Lewis Carroll, the Zeno-like problem of how a ‘proof’ ever gets started. Suppose I have as premises (i) ‘p’ and (ii) p ➝ q. Can I infer ‘q’? Only, it seems, if I am sure of (iii) (p & p ➝q) ➝ q. Can I then infer ‘q’? Only, it seems, if I am sure that (iv) (p & p ➝ q & (p & p ➝ q) ➝ q) ➝ q. For each new axiom (N) I need a further axiom (N + 1) telling me that the set so far implies ‘q’, and the regress never stops. The usual solution is to treat a system as containing not only axioms, but also rules of inference, allowing movement from the axioms. The rule ‘modus ponens’ allow ‘us’ to pass from the first premise to ‘q’. Carroll’s puzzle shows that distinguishing two theoretical categories is essential, although there may be choice about which theses to put in which category.
 Traditionally, a proposition that is not a ‘conditional’, as with the ‘affirmative’ and ‘negative’, modern opinion is wary of the distinction, since what appears categorical may vary with the choice of a primitive vocabulary and notation. Apparently categorical propositions may also turn out to be disguised conditionals: ‘X’ is intelligent (categorical?) Equivalent, if ‘X’ is given a range of tasks, she does them better than many people (conditional?). The problem is not merely one of classification, since deep metaphysical questions arise when facts that seem to be categorical and therefore solid, come to seem by contrast conditional, or purely hypothetical or potential.
 Its condition of some classified necessity is so proven sufficient that if ‘p’ is a necessary condition of ‘q’, then ‘q’ cannot be true unless ‘p’; is true? If ‘p’ is a sufficient condition, thus steering well is a necessary condition of driving in a satisfactory manner, but it is not sufficient, for one can steer well but drive badly for other reasons. Confusion may result if the distinction is not heeded. For example, the statement that ‘A’ causes ‘B’ may be interpreted to mean that ‘A’ is itself a sufficient condition for ‘B’, or that it is only a necessary condition fort ‘B’, or perhaps a necessary parts of a total sufficient condition. Lists of conditions to be met for satisfying some administrative or legal requirement frequently attempt to give individually necessary and jointly sufficient sets of conditions.
 What is more, that if any proposition of the form ‘if p then q’. The condition hypothesized, ‘p’. Is called the antecedent of the conditionals, and ‘q’, the consequent? Various kinds of conditional have been distinguished.  Its weakest is that of ‘material implication’, merely telling that either ‘not-p’, or ‘q’. Stronger conditionals include elements of ‘modality’, corresponding to the thought that ‘if p is truer then q must be true’. Ordinary language is very flexible in its use of the conditional form, and there is controversy whether conditionals are better treated semantically,  yielding differently finds of conditionals with different meanings, or pragmatically, in which case there should be one basic meaning with surface differences arising from other implicatures.
 It follows from the definition of ‘strict implication’ that a necessary proposition is strictly implied by any proposition, and that an impossible proposition strictly implies any proposition. If strict implication corresponds to ‘q follows from p’, then this means that a necessary proposition follows from anything at all, and anything at all follows from an impossible proposition. This is a problem if we wish to distinguish between valid and invalid arguments with necessary conclusions or impossible premises.
 The Humean problem of induction is that if we would suppose that there is some property ‘A’ concerning and observational or an experimental situation, and that out of a large number of observed instances of ‘A’, some fraction m/n (possibly equal to 1) has also been instances of some logically independent property ‘B’. Suppose further that the background proportionate circumstances not specified in these descriptions has been varied to a substantial degree and that there is no collateral information available concerning the frequency of ‘B’s’ among ‘A’s or concerning causal or nomologically connections between instances of ‘A’ and instances of ‘B’.
 In this situation, an ‘enumerative’ or ‘instantial’ induction inference would move rights from the premise, that m/n of observed ‘A’s’ are ‘B’s’ to the conclusion that approximately m/n of all ‘A’s’ are ‘B’s. (The usual probability qualification will be assumed to apply to the inference, rather than being part of the conclusion.) Here the class of ‘A’s’ should be taken to include not only unobserved ‘A’s’ and future ‘A’s’, but also possible or hypothetical ‘A’s’ (an alternative conclusion would concern the probability or likelihood of the adjacently observed ‘A’ being a ‘B’).
 The traditional or Humean problem of induction, often referred to simply as ‘the problem of induction’, is the problem of whether and why inferences that fit this schema should be considered rationally acceptable or justified from an epistemic or cognitive standpoint, i.e., whether and why reasoning in this way is likely to lead to true claims about the world. Is there any sort of argument or rationale that can be offered for thinking that conclusions reached in this way are likely to be true in the corresponding premisses is true  ‒or even that their chances of truth are significantly enhanced?
 Hume’s discussion of this issue deals explicitly only with cases where all observed ‘A’s’ are ‘B’s’ and his argument applies just as well to the more general case. His conclusion is entirely negative and sceptical: Inductive inferences are not rationally justified, but are instead the result of an essentially a-rational process, custom or habit. Hume (1711-76) challenges the proponent of induction to supply a cogent line of reasoning that leads from an inductive premise to the corresponding conclusion and offers an extremely influential argument in the form of a dilemma (a few times referred to as ‘Hume’s fork’), that either our actions are determined, in which case we are not responsible for them, or they are the result of random events, under which case we are also not responsible for them.
 Such reasoning would, he argues, have to be either deductively demonstrative reasoning in the concerning relations of ideas or ‘experimental’, i.e., empirical, that reasoning concerning matters of fact or existence. It cannot be the former, because all demonstrative reasoning relies on the avoidance of contradiction, and it is not a contradiction to suppose that ‘the course of nature may change’, that an order that was observed in the past and not of its continuing against the future: But it cannot be, as the latter, since any empirical argument would appeal to the success of such reasoning about an experience, and the justifiability of generalizing from experience are precisely what is at issue-so that any such appeal would be question-begging. Hence, Hume concludes that there can be no such reasoning (1748).
 An alternative version of the problem may be obtained by formulating it with reference to the so-called Principle of Induction, which says roughly that the future will resemble the past or, somewhat better, that unobserved cases will resemble observed cases. An inductive argument may be viewed as enthymematic, with this principle serving as a supposed premiss, in which case the issue is obviously how such a premiss can be justified. Hume’s argument is then that no such justification is possible: The principle cannot be justified a prior because having possession of been true in experiences without obviously begging the question is not contradictory to have possession of been true in experiences without obviously begging the question.
 The predominant recent responses to the problem of induction, at least in the analytic tradition, in effect accept the main conclusion of Hume’s argument, namely, that inductive inferences cannot be justified in the sense of showing that the conclusion of such an inference is likely to be true if the premise is true, and thus attempt to find another sort of justification for induction. Such responses fall into two main categories: (i) Pragmatic justifications or ‘vindications’ of induction, mainly developed by Hans Reichenbach (1891-1953), and (ii) ordinary language justifications of induction, whose most important proponent is Frederick, Peter Strawson (1919-). In contrast, some philosophers still attempt to reject Hume’s dilemma by arguing either (iii) That, contrary to appearances, induction can be inductively justified without vicious circularity, or (iv) that an anticipatory justification of induction is possible after all. In that:
   (1) Reichenbach’s view is that induction is best regarded, not as a form of inference, but rather as a ‘method’ for arriving at posits regarding, i.e., the proportion of ‘A’s’ remain additionally of ‘B’s’. Such a posit is not a claim asserted to be true, but is instead an intellectual wager analogous to a bet made by a gambler. Understood in this way, the inductive method says that one should posit that the observed proportion is, within some measure of an approximation, the true proportion and then continually correct that initial posit as new information comes in.
 The gambler’s bet is normally an ‘appraised posit’, i.e., he knows the chances or odds that the outcome on which he bets will actually occur. In contrast, the inductive bet is a ‘blind posit’: We do not know the chances that it will succeed or even that success is that it will succeed or even that success is possible. What we are gambling on when we make such a bet is the value of a certain proportion in the independent world, which Reichenbach construes as the limit of the observed proportion as the number of cases increases to infinity. Nevertheless, we have no way of knowing that there are even such a limit, and no way of knowing that the proportion of ‘A’s’ are in addition of ‘B’s’ converges in the end on some stable value than varying at random. If we cannot know that this limit exists, then we obviously cannot know that we have any definite chance of finding it.
 What we can know, according to Reichenbach, is that ‘if’ there is a truth of this sort to be found, the inductive method will eventually find it’. That this is so is an analytic consequence of Reichenbach’s account of what it is for such a limit to exist. The only way that the inductive method of making an initial posit and then refining it in light of new observations can fail eventually to arrive at the true proportion is if the series of observed proportions never converges on any stable value, which means that there is no truth to be found pertaining the proportion of ‘A’s additionally constitute ‘B’s’. Thus, induction is justified, not by showing that it will succeed or indeed, that it has any definite likelihood of success, but only by showing that it will succeed if success is possible. Reichenbach’s claim is that no more than this can be established for any method, and hence that induction gives ‘us’ our best chance for success, our best gamble in a situation where there is no alternative to gambling.
 This pragmatic response to the problem of induction faces several serious problems. First, there are indefinitely many other ‘methods’ for arriving at posits for which the same sort of defence can be given-methods that yield the same results as the inductive method over time but differ arbitrarily before long. Despite the efforts of others, it is unclear that there is any satisfactory way to exclude such alternatives, in order to avoid the result that any arbitrarily chosen short-term posit is just as reasonable as the inductive posit. Second, even if there is a truth of the requisite sort to be found, the inductive method is only guaranteed to find it or even to come within any specifiable distance of it in the indefinite long run. All the same, any actual application of inductive results always takes place in the presence to the future eventful states in making the relevance of the pragmatic justification to actual practice uncertainly. Third, and most important, it needs to be emphasized that Reichenbach’s response to the problem simply accepts the claim of the Humean sceptic that an inductive premise never provides the slightest reason for thinking that the corresponding inductive conclusion is true. Reichenbach himself is quite candid on this point, but this does not alleviate the intuitive implausibility of saying that we have no more reason for thinking that our scientific and commonsense conclusions that result in the induction of it ‘ . . .  is true’ than, to use Reichenbach’s own analogy (1949), a blind man wandering in the mountains who feels an apparent trail with his stick has for thinking that following it will lead him to safety.
 An approach to induction resembling Reichenbach’s claiming in that those particular inductive conclusions are posits or conjectures, than the conclusions of cogent inferences, is offered by Popper. However, Popper’s view is even more overtly sceptical: It amounts to saying that all that can ever be said in favour of the truth of an inductive claim is that the claim has been tested and not yet been shown to be false.
   (2) The ordinary language response to the problem of induction has been advocated by many philosophers, none the less, Strawson claims that the question whether induction is justified or reasonable makes sense only if it tacitly involves the demand that inductive reasoning meet the standards appropriate to deductive reasoning, i.e., that the inductive conclusions are shown to follow deductively from the inductive assumption. Such a demand cannot, of course, be met, but only because it is illegitimate: Inductive and deductive reasons are simply fundamentally different kinds of reasoning, each possessing its own autonomous standards, and there is no reason to demand or expect that one of these kinds meet the standards of the other. Whereas, if induction is assessed by inductive standards, the only ones that are appropriate, then it is obviously justified.
 The problem here is to understand to what this allegedly obvious justification of an induction amount. In his main discussion of the point (1952), Strawson claims that it is an analytic true statement that believing it a conclusion for which there is strong evidence is reasonable and an analytic truth that inductive evidence of the sort captured by the schema presented earlier constitutes strong evidence for the corresponding inductive conclusion, thus, apparently yielding the analytic conclusion that believing it a conclusion for which there is inductive evidence is reasonable. Nevertheless, he also admits, indeed insists, that the claim that inductive conclusions will be true in the future is contingent, empirical, and may turn out to be false (1952). Thus, the notion of reasonable belief and the correlative notion of strong evidence must apparently be understood in ways that have nothing to do with likelihood of truth, presumably by appeal to the standard of reasonableness and strength of evidence that are accepted by the community and are embodied in ordinary usage.
 Understood in this way, Strawson’s response to the problem of inductive reasoning does not speak to the central issue raised by Humean scepticism: The issue of whether the conclusions of inductive arguments are likely to be true. It amounts to saying merely that if we reason in this way, we can correctly call ourselves ‘reasonable’ and our evidence ‘strong’, according to our accepted community standards. Nevertheless, to the undersealing of issue of wether following these standards is a good way to find the truth, the ordinary language response appears to have nothing to say.
   (3) The main attempts to show that induction can be justified inductively have concentrated on showing that such as a defence can avoid circularity. Skyrms (1975) formulate, perhaps the clearest version of this general strategy. The basic idea is to distinguish different levels of inductive argument: A first level in which induction is applied to things other than arguments: A second level in which it is applied to arguments at the first level, arguing that they have been observed to succeed so far and hence are likely to succeed in general: A third level in which it is applied in the same way to arguments at the second level, and so on. Circularity is allegedly avoided by treating each of these levels as autonomous and justifying the argument at each level by appeal to an argument at the next level.
 One problem with this sort of move is that even if circularity is avoided, the movement to higher and higher levels will clearly eventually fail simply for lack of evidence: A level will reach at which there have been enough successful inductive arguments to provide a basis for inductive justification at the next higher level, and if this is so, then the whole series of justifications collapses. A more fundamental difficulty is that the epistemological significance of the distinction between levels is obscure. If the issue is whether reasoning in accord with the original schema offered above ever provides a good reason for thinking that the conclusion is likely to be true, then it still seems question-begging, even if not flatly circular, to answer this question by appeal to anther argument of the same form.
   (4) The idea that induction can be justified on a pure priori basis is in one way the most natural response of all: It alone treats an inductive argument as an independently cogent piece of reasoning whose conclusion can be seen rationally to follow, although perhaps only with probability from its premise. Such an approach has, however, only rarely been advocated (Russell, 19132 and BonJour, 1986), and is widely thought to be clearly and demonstrably hopeless.
 Many on the reasons for this pessimistic view depend on general epistemological theses about the possible or nature of anticipatory cognition. Thus if, as Quine alleges, there is no a prior justification of any kind, then obviously a prior justification for induction is ruled out. Or if, as more moderate empiricists have in claiming some preexistent knowledge should be analytic, then again a prevenient justification for induction seems to be precluded, since the claim that if an inductive premise ids truer, then the conclusion is likely to be true does not fit the standard conceptions of ‘analyticity’. A consideration of these matters is beyond the scope of the present spoken exchange.
 There are, however, two more specific and quite influential reasons for thinking that an early approach is impossible that can be briefly considered, first, there is the assumption, originating in Hume, but since adopted by very many of others, that a move forward in  the defence of induction would have to involve ‘turning induction into deduction’, i.e., showing, per impossible, that the inductive conclusion follows deductively from the premise, so that it is a formal contradiction to accept the latter and deny the former. However, it is unclear why a prior approach need be committed to anything this strong. It would be enough if it could be argued that it is deductively unlikely that such a premise is true and corresponding conclusion false.
 Second, Reichenbach defends his view that pragmatic justification is the best that is possible by pointing out that a completely chaotic world in which there is simply not true conclusion to be found as to the proportion of ‘A’s’ in addition that occurs of, but B’s’ is neither impossible nor unlikely from a purely a prior standpoint, the suggestion being that therefore there can be no a prior reason for thinking that such a conclusion is true. Nevertheless, there is still a substring wayin laying that a chaotic world is a prior neither impossible nor unlikely without any further evidence does not show that such a world os not a prior unlikely and a world containing such-and-such regularity might anticipatorially be somewhat likely in relation to an occurrence of a long-run patten of evidence in which a certain stable proportion of observed ‘A’s’ are ‘B’s’ ~. An occurrence, it might be claimed, that would be highly unlikely in a chaotic world (BonJour, 1986).
 Goodman’s ‘new riddle of induction’ purports that we suppose that before some specific time ’t’ (perhaps the year 2000) we observe a larger number of emeralds (property A) and find them all to be green (property B). We proceed to reason inductively and conclude that all emeralds are green Goodman points out, however, that we could have drawn a quite different conclusion from the same evidence. If we define the term ‘grue’ to mean ‘green if examined before ’t’ and blue examined after t ʹ, then all of our observed emeralds will also be gruing.  A parallel inductive argument will yield the conclusion that all emeralds are gruing, and hence that all those examined after the year 2000 will be blue. Presumably the first of these concisions is genuinely supported by our observations and the second is not.  Nevertheless, the problem is to say why this is so and to impose some further restriction upon inductive reasoning that will permit the first argument and exclude the second.
 The obvious alternative suggestion is that ‘grue.  Similar predicates do not correspond to genuine, purely qualitative properties in the way that ‘green’ and ‘blueness’ does, and that this is why inductive arguments involving them are unacceptable. Goodman, however, claims to be unable to make clear sense of this suggestion, pointing out that the relations of formal desirability are perfectly symmetrical: Grue’ may be defined in terms if, ‘green’ and ‘blue’, but ‘green’ an equally well be defined in terms of ‘grue’ and ‘green’ (blue if examined before ‘t’ and green if examined after ‘t’).
 The ‘grued, paradoxes’ demonstrate the importance of categorization, in that sometimes it is itemized as ‘gruing’, if examined of a presence to the future, before future time ‘t’ and ‘green’, or not so examined and ‘blue’. Even though all emeralds in our evidence class grue, we ought must infer that all emeralds are gruing. For ‘grue’ is unprojectible, and cannot transmit credibility form known to unknown cases. Only projectable predicates are right for induction. Goodman considers entrenchment the key to projectibility having a long history of successful protection, ‘grue’ is entrenched, lacking such a history, ‘grue’ is not. A hypothesis is projectable, Goodman suggests, only if its predicates (or suitable related ones) are much better entrenched than its rivalrous past successes that do not assume future ones. Induction remains a risky business. The rationale for favouring entrenched predicates is pragmatic. Of the possible projections from our evidence class, the one that fits with past practices enables ‘us’ to utilize our cognitive resources best. Its prospects of being true are worse than its competitors’ and its cognitive utility is greater.
 So, to a better understanding of induction we should then term is most widely used for any process of reasoning that takes ‘us’ from empirical premises to empirical conclusions supported by the premises, but not deductively entailed by them. Inductive arguments are therefore kinds of applicative arguments, in which something beyond the content of the premise is inferred as probable or supported by them. Induction is, however, commonly distinguished from arguments to theoretical explanations, which share this applicative character, by being confined to inferences in which he conclusion involves the same properties or relations as the premises. The central example is induction by simple enumeration, where from premises telling that Fa, Fb, Fc . . . ‘where a, b, C’s, are all of some kind ‘G’, it is inferred that G’s from outside the sample, such as future G’s, will be ‘F’, or perhaps that all G’s are ‘F’. In this, which and the other persons deceive them, children may infer that everyone is a deceiver: Different, but similar inferences of a property by some object to the same object’s future possession of the same property, or from the constancy of some law-like pattern in events and states of affairs ti its future constancy. All objects we know of attract each other with a force inversely proportional to the square of the distance between them, so perhaps they all do so, and will always do so.
 The rational basis of any inference was challenged by Hume, who believed that induction presupposed belie in the uniformity of nature, but that this belief has no defence in reason, and merely reflected a habit or custom of the mind. Hume was not therefore sceptical about the role of reason in either explaining it or justifying it. Trying to answer Hume and to show that there is something rationally compelling about the inference referred to as the problem of induction. It is widely recognized that any rational defence of induction will have to partition well-behaved properties for which the inference is plausible (often called projectable properties) from badly behaved ones, for which it is not. It is also recognized that actual inductive habits are more complex than those of similar enumeration, and that both common sense and science pay attention to such giving factors as variations within the sample giving ‘us’ the evidence, the application of ancillary beliefs about the order of nature, and so on.
 Nevertheless, the fundamental problem remains that ant experience condition by application show ‘us’ only events occurring within a very restricted part of a vast spatial and temporal order about which we then come to believe things.
 Uncompounded by its belonging of a confirmation theory finding of the measure to which evidence supports a theory fully formalized confirmation theory would dictate the degree of confidence that a rational investigator might have in a theory, given some-body of evidence. The grandfather of confirmation theory is Gottfried Leibniz (1646-1718), who believed that a logically transparent language of science would be able to resolve all disputes. In the 20th century a fully formal confirmation theory was a main goal of the logical positivist, since without it the central concept of verification by empirical evidence itself remains distressingly unscientific. The principal developments were due to Rudolf Carnap (1891-1970), culminating in his “Logical Foundations of Probability” (1950). Carnap’s idea was that the measure necessitated would be the proportion of logically possible states of affairs in which the theory and the evidence both hold, compared ti the number in which the evidence itself holds that the probability of a preposition, relative to some evidence, is a proportion of the range of possibilities under which the proposition is true, compared to the total range of possibilities left by the evidence. The difficulty with the theory lies in identifying sets of possibilities so that they admit of measurement. It therefore demands that we can put a measure on the ‘range’ of possibilities consistent with theory and evidence, compared with the range consistent with the evidence alone.
 Among the obstacles the enterprise meets, is the fact that while evidence covers only a finite range of data, the hypotheses of science may cover an infinite range. In addition, confirmation proves to vary with the language in which the science is couched, and the Carnapian programme has difficulty in separating genuinely confirming variety of evidence from less compelling repetition of the same experiment. Confirmation also proved to be susceptible to acute paradoxes. Finally, scientific judgement seems to depend on such intangible factors as the problems facing rival theories, and most workers have come to stress instead the historically situated scene of what would appear as a plausible distinction of a scientific knowledge at a given time.
 Arose to the paradox of which when a set of apparent incontrovertible premises is given to unacceptable or contradictory conclusions. To solve a paradox will involve showing either that there is a hidden flaw in the premises, or that the reasoning is erroneous, or that the apparently unacceptable conclusion can, in fact, be tolerated. Paradoxes are therefore important in philosophy, for until one is solved it shows that there is something about our reasoning and our concepts that we do not understand. What is more, and somewhat loosely, a paradox is a compelling argument from unacceptable premises to an unacceptable conclusion: More strictly speaking, a paradox is specified to be a sentence that is true if and only if it is false. A characterized objection lesson of it would be: “The displayed sentence is false.”
 Seeing that this sentence is false if true is easy, and true if false, a paradox, in either of the senses distinguished, presents an important philosophical challenger. Epistemologists are especially concerned with various paradoxes having to do with knowledge and belief. In other words, for example, the Knower paradox is an argument that begins with apparently impeccable premisses about the concepts of knowledge and inference and derives an explicit contradiction. The origin of the reasoning is the ‘surprise examination paradox’: A teacher announces that there will be a surprise examination next week. A clever student argues that this is impossible. ‘The test cannot be on Friday, the last day of the week, because it would not be a surprise. We would know the day of the test on Thursday evening. This means we can also rule out Thursday. For after we learn that no test has been given by Wednesday, we would know the test is on Thursday or Friday -and would already know that it s not on Friday and would already know that it is not on Friday by the previous reasoning. The remaining days can be eliminated in the same manner’.
 This puzzle has over a dozen variants. The first was probably invented by the Swedish mathematician Lennard Ekbon in 1943. Although the first few commentators regarded the reverse elimination argument as cogent, every writer on the subject since 1950 agrees that the argument is unsound. The controversy has been over the proper diagnosis of the flaw.
 Initial analyses of the subject’s argument tried to lay the blame on a simple equivocation. Their failure led to more sophisticated diagnoses. The general format has been an assimilation to better-known paradoxes. One tradition casts the surprise examination paradox as a self-referential problem, as fundamentally akin to the Liar, the paradox of the Knower, or Gödel’s incompleteness theorem. That in of itself, says enough that Kaplan and Montague (1960) distilled the following ‘self-referential’ paradox, the Knower. Consider the sentence:
(S) The negation of this sentence is known (to be true).
Suppose that (S) is true. Then its negation is known and hence true. However, if its negation is true, then (S) must be false. Therefore (s) is false, or what is the name, the negation of (S) is true.
 This paradox and its accompanying reasoning are strongly reminiscent of the Lair Paradox that (in one version) begins by considering a sentence ‘This sentence is false’ and derives a contradiction. Versions of both arguments using axiomatic formulations of arithmetic and Gödel-numbers to achieve the effect of self-reference yields important meta-theorems about what can be expressed in such systems. Roughly these are to the effect that no predicates definable in the formalized arithmetic can have the properties we demand of truth (Tarski’s Theorem) or of knowledge (Montague, 1963).
 These meta-theorems still leave ‘us; with the problem that if we suppose that we add of these formalized languages predicates intended to express the concept of knowledge (or truth) and inference-as one mighty does if a logic of these concepts is desired. Then the sentence expressing the leading principles of the Knower Paradox will be true.
Explicitly, the assumption about knowledge and inferences are:
  (1) If sentences ‘A’ are known, then “a.”
  (2) (1) is known?
  (3) If ‘B’ is correctly inferred from ‘A’, and ‘A’ is known, then ‘B’ id known.
To give an absolutely explicit t derivation of the paradox by applying these principles to (S), we must add (contingent) assumptions to the effect that certain inferences have been done. Still, as we go through the argument of the Knower, these inferences are done. Even if we can somehow restrict such principles and construct a consistent formal logic of knowledge and inference, the paradoxical argument as expressed in the natural language still demands some explanation.
 The usual proposals for dealing with the Liar often have their analogues for the Knower, e.g., that there is something wrong with a self-reference or that knowledge (or truth) is properly a predicate of propositions and not of sentences. The relies that show that some of these are not adequate are often parallel to those for the Liar paradox. In addition, on e C an try here what seems to be an adequate solution for the Surprise Examination Paradox, namely the observation that ‘new knowledge can drive out knowledge’, but this does not seem to work on the Knower (Anderson, 1983).
 There are a number of paradoxes of the Liar family. The simplest example is the sentence ‘This sentence is false’, which must be false if it is true, and true if it is false. One suggestion is that the sentence fails to say anything, but sentences that fail to say anything are at least not true. In fact case, we consider to sentences ‘This sentence is not true’, which, if it fails to say anything is not true, and hence (this kind of reasoning is sometimes called the strengthened Liar). Other versions of the Liar introduce pairs of sentences, as in a slogan on the front of a T-shirt saying ‘This sentence on the back of this T-shirt is false’, and one on the back saying ‘The sentence on the front of this T-shirt is true’. It is clear that each sentence individually is well formed, and was it not for the other, might have said something true. So any attempts to dismiss the paradox by sating that the sentence involved are meaningless will face problems.
 Even so, the two approaches that have some hope of adequately dealing with this paradox is ‘hierarchy’ solutions and ‘truth-value gap’ solutions. According to the first, knowledge is structured into ‘levels’. It is argued that there be one-coherent notion expressed by the verb; knows’, but rather a whole series of notions: knows0. knows, and so on (perhaps into transfinite), stated ion terms of predicate expressing such ‘ramified’ concepts and properly restricted, (1)-(3) lead to no contradictions. The main objections to this procedure are that the meaning of these levels has not been adequately explained and that the idea of such subscripts, even implicit, in a natural language is highly counterintuitive the ‘truth-value gap’ solution takes sentences such as (S) to lack truth-value. They are neither true nor false, but they do not express propositions. This defeats a crucial step in the reasoning used in the derivation of the paradoxes. Kripler (1986) has developed this approach in connection with the Liar and Asher and Kamp (1986) has worked out some details of a parallel solution to the Knower. The principal objection is that ‘strengthened’ or ‘super’ versions of the paradoxes tend to reappear when the solution itself is stated.
 Since the paradoxical deduction uses only the properties (1)-(3) and since the argument is formally valid, any notions that satisfy these conditions will lead to a paradox. Thus, Grim (1988) notes that this may be read as ‘is known by an omniscient God’ and concludes that there is no coherent single notion of omniscience. Thomason (1980) observes that with some different conditions, analogous reasoning about belief can lead to paradoxical consequence.
 Overall, it looks as if we should conclude that knowledge and truth are ultimately intrinsically ‘stratified’ concepts. It would seem that wee must simply accept the fact that these (and similar) concepts cannot be assigned of any-one fixed, finite or infinite. Still, the meaning of this idea certainly needs further clarification.
 Its paradox arises when a set of apparently incontrovertible premises gives unacceptable or contradictory conclusions, to solve a paradox will involve showing either that there is a hidden flaw in the premises, or that the reasoning is erroneous, or that the apparently unacceptable conclusion can, in fact, be tolerated. Paradoxes are therefore important in philosophy, for until one is solved its show that there is something about our reasoning and our concepts that we do not understand. Famous families of paradoxes include the ‘semantic paradoxes’ and ‘Zeno’s paradoxes. Art the beginning of the 20th century, paradox and other set-theoretical paradoxes led to the complete overhaul of the foundations of set theory, while the ’Sorites paradox’ has lead to the investigations of the semantics of vagueness and fuzzy logics.
 It is, however, to what extent can analysis be informative? This is the question that gives a riser to what philosophers has traditionally called ‘the’ paradox of analysis. Thus, consider the following proposition:
 (1) To be an instance of knowledge is to be an instance of justified true belief not essentially grounded in any falsehood.
(1) if true, illustrates an important type of philosophical analysis. For convenience of exposition, I will assume (1) is a correct analysis. The paradox arises from the fact that if the concept of justified true belief not been essentially grounded in any falsification is the analysand of the concept of knowledge, it would seem that they are the same concept and hence that:
(2) To be an instance of knowledge is to be as an instance of.
knowledge and would have to be the same propositions as (1). But then how can (1) be informative when (2) is not? This is what is called the first paradox of analysis. Classical writings’ on analysis suggests a second paradoxical analysis (Moore, 1942).
 (3) An analysis of the concept of being a brother is that to be a
brother is to be a male sibling. If (3) is true, it would seem that the concept of being a brother would have to be the same concept as the concept of being a male sibling and tat:
 (4) An analysis of the concept of being a brother is that to be a brother is to be a brother
would also have to be true and in fact, would have to be the same proposition as (3?). Yet (3) is true and (4) is false.
 Both these paradoxes rest upon the assumptions that analysis is a relation between concepts, than one involving entity of other sorts, such as linguistic expressions, and tat in a true analysis, analysand and analysandum are the same concept. Both these assumptions are explicit in Moore, but some of Moore’s remarks hint at a solution to that of another statement of an analysis is a statement partly about the concept involved and partly about the verbal expressions used to express it. He says he thinks a solution of this sort is bound to be right, but fails to suggest one because he cannot see a way in which the analysis can be even partly about the expression (Moore, 1942).
  Elsewhere, of such ways, as a solution to the second paradox, to which is explicating (3) as:
 (5) An analysis is given by saying that the verbal expression ‘χ is a brother’ expresses the same concept as is expressed by the conjunction of the verbal expressions ‘χ is male’ when used to express the concept of being male and ‘χ is a sibling’ when used to express the concept of being a sibling. (Ackerman, 1990).
An important point about (5) is as follows. Stripped of its philosophical jargon (‘analysis’, ‘concept’, ‘χ is a  . . . ‘), (5) seems to state the sort of information generally stated in a definition of the verbal expression ‘brother’ in terms of the verbal expressions ‘male’ and ‘sibling’, where this definition is designed to draw upon listeners’ antecedent understanding of the verbal expression ‘male’ and ‘sibling’, and thus, to tell listeners what the verbal expression ‘brother’ really means, instead of merely providing the information that two verbal expressions are synonymous without specifying the meaning of either one. Thus, its solution to the second paradox seems to make the sort of analysis tat gives rise to this paradox matter of specifying the meaning of a verbal expression in terms of separate verbal expressions already understood and saying how the meanings of these separate, already-understood verbal expressions are combined. This corresponds to Moore’s intuitive requirement that an analysis should both specify the constituent concepts of the analysandum and tell how they are combined, but is this all there is to philosophical analysis?
 To answer this question, we must note that, in addition too there being two paradoxes of analysis, there is two types of analyses that are relevant here. (There are also other types of analysis, such as reformatory analysis, where the analysands are intended to improve on and replace the analysandum. But since reformatory analysis involves no commitment to conceptual identity between analysand and analysandum, reformatory analysis does not generate a paradox of analysis and so will not concern ‘us’ here.) One way to recognize the difference between the two types of analysis concerning ‘us’ here is to focus on the difference between the two paradoxes. This can be done by means of the Frége-inspired sense-individuation condition, which is the condition that two expressions have the same sense if and only if they can be interchangeably ‘salva veritate’ whenever used in propositional attitude context. If the expressions for the analysands and the analysandum in (1) met this condition, (1) and (2) would not raise the first paradox, but the second paradox arises regardless of whether the expression for the analysand and the analysandum meet this condition. The second paradox is a matter of the failure of such expressions to be interchangeable salva veritate in sentences involving such contexts as ‘an analysis is given thereof. Thus, a solution (such as the one offered) that is aimed only at such contexts can solve the second paradox. This is clearly false for the first paradox, however, which will apply to all pairs of propositions expressed by sentences in which expressions for pairs of analysands and anslysantia raising the first paradox is interchangeable. For example, consider the following proposition:
 (6) Mary knows that some cats tail.
It is possible for John to believe (6) without believing:
 (7) Mary has justified true belief, not essentially grounded in any falsehood, that some cats lack tails.
Yet this possibility clearly does not mean that the proposition that Mary knows that some casts lack tails is partly about language.
 One approach to the first paradox is to argue that, despite the apparent epistemic inequivalence of (1) and (2), the concept of justified true belief not essentially grounded in any falsehood is still identical with the concept of knowledge (Sosa, 1983). Another approach is to argue that in the sort of analysis raising the first paradox, the analysand and analysandum is concepts that are different but that bear a special epistemic relation to each other. Elsewhere, the development is such an approach and suggestion that this analysand-analysandum relation has the following facets.
 (a) The analysand and analysandum are necessarily coextensive, i.e., necessarily every instance of one is an instance of the other.
 (b) The analysand and analysandum are knowable theoretical to be coextensive.
 © The analysandum is simpler than the analysands a condition whose necessity is recognized in classical writings on analysis, such as, Langford, 1942.
 (d) The analysand do not have the analysandum as a constituent.
Condition (d) rules out circularity. But since many valuable quasi-analyses are partly circular, e.g., knowledge is justified true belief supported by known reasons not essentially grounded in any falsehood, it seems best to distinguish between full analysis, from that of (d) is a necessary condition, and partial analysis, for which it is not.
These conditions, while necessary, are clearly insufficient. The basic problem is that they apply too many pairs of concepts that do not seem closely enough related epistemologically to count as analysand and analysandum. , such as the concept of being 6 and the concept of the fourth root of 1296. Accordingly, its solution upon what actually seems epistemologically distinctive about analyses of the sort under consideration, which is a certain way they can be justified. This is by the philosophical example-and-counterexample method, which is in a general term that goes as follows. ‘J’ investigates the analysis of K’s concept ‘Q’ (where ‘K’ can but need not be identical to ‘J’ by setting ‘K’ a series of armchair thought experiments, i.e., presenting ‘K’ with a series of simple described hypothetical test cases and asking ‘K’ questions of the form ‘If such-and-such where the case would this count as a case of Q? ‘J’ then contrasts the descriptions of the cases to which; K’ answers affirmatively with the description of the cases to which ‘K’ does not, and ‘J’ generalizes upon these descriptions to arrive at the concepts (if possible not including the analysandum) and their mode of combination that constitute the analysand of K’‘s concept ‘Q’. Since ‘J’ need not be identical with ‘K’, there is no requirement that ‘K’ himself be able to perform this generalization, to recognize its result as correct, or even to understand he analysand that is its result. This is reminiscent of Walton’s observation that one can simply recognize a bird as a swallow without realizing just what feature of the bird (beak, wing configurations, etc.) form the basis of this recognition. (The philosophical significance of this way of recognizing is discussed in Walton, 1972) ‘K’ answers the questions based solely on whether the described hypothetical cases just strike him as cases of ‘Q’. ‘J’ observes certain strictures in formulating the cases and questions. He makes the cases as simple as possible, to minimize the possibility of confusion and to minimize the likelihood that ‘K’ will draw upon his philosophical theories (or quasi-philosophical, a rudimentary notion if he is unsophisticated philosophically) in answering the questions. For this conflicting result, the conflict should ‘other things being equal’ be resolved in favour of the simpler case. ‘J’ makes the series of described cases wide-ranging and varied, with the aim of having it be a complete series, where a series is complete if and only if no case that is omitted in such that, if included, it would change the analysis arrived at. ‘J’ does not, of course, use as a test-case description anything complicated and general enough to express the analysand. There is no requirement that the described hypothetical test cases be formulated only in terms of what can be observed. Moreover, using described hypothetical situations as test cases enables ‘J’ to frame the questions in such a way as to rule out extraneous background assumption to a degree, thus, even if ‘K’ correctly believes that all and only P’s are R’s, the question of whether the concepts of P, R, or both enter the analysand of his concept ‘Q’ can be investigated by asking him such questions as ‘Suppose (even if it seems preposterous to you) that you were to find out that there was a ‘P’ that was not an ‘R’. Would you still consider it a case of Q?
 Taking all this into account, the fifth necessary condition for this sort of analysand-analysandum relations is as follows:
 (e) If ‘S’ is the analysand of ‘Q’, the proposition that necessarily all and only instances of ‘S’ are instances of ‘Q’ can be justified by generalizing from intuition about the correct answers to questions of the sort indicated about a varied and wide-ranging series of simple described hypothetical situations. It so does occur of antinomy, when we are able to argue for, or demonstrate, both a proposition and its contradiction, roughly speaking, a contradiction of a proposition ‘p’ is one that can be expressed in form ‘not-p’, or, if ‘p’ can be expressed in the form ‘not-q’, then a contradiction is one that can be expressed in the form ‘q’. Thus, e.g., if ‘p is 2 + 1 = 4, then      2 + 1 ≠ 4 is the contradictory of ‘p’, for
2 + 1 ≠ 4 can be expressed in the form not (2 + 1 = 4). If ‘p’ is 2 + 1 ≠ 4, then 2 + 1-4 is a contradictory of ‘p’, since 2 + 1 ≠ 4 can be expressed in the form not (2 + 1 = 4). This is, mutually, but contradictory propositions can be expressed in the form, ‘r’, ‘not-r’. The Principle of Contradiction says that mutually contradictory propositions cannot both be true and cannot both be false. Thus, by this principle, since if ‘p’ is true, ‘not-p’ is false, no proposition ‘p’ can be at once true and false (otherwise both ‘p’ and its contradictories would be false?). In particular, for any predicate ‘p’ and object ‘χ’, it cannot be that ‘p’; is at once true of ‘χ’ and false of χ? This is the classical formulation of the principle of contradiction, but it is nonetheless, that wherein, we cannot now fault either demonstrates. We would eventually hope to be able ‘to solve the antinomy’ by managing, through careful thinking and analysis, eventually to fault either or both demonstrations.
 Many paradoxes are as an easy source of antinomies, for example, Zeno gave some famously lets say, logical-cum-mathematical arguments that might be interpreted as demonstrating that motion is impossible. But our eyes as it was, demonstrate motion (exhibit moving things) all the time. Where did Zeno go wrong? Where do our eyes go wrong? If we cannot readily answer at least one of these questions, then we are in antinomy. In the “Critique of Pure Reason,” Kant gave demonstrations of the same kind -in the Zeno example they were obviously not the same kind of both, e.g., that the world has a beginning in time and space, and that the world has no beginning in time or space. He argues that both demonstrations are at fault because they proceed on the basis of ‘pure reason’ unconditioned by sense experience.
 At this point, we display attributes to the theory of experience, as it is not possible to define in an illuminating way, however, we know what experiences are through acquaintances with some of our own, e.g., visual experiences of as afterimage, a feeling of physical nausea or a tactile experience of an abrasive surface (which might be caused by an actual surface -rough or smooth, or which might be part of a dream, or the product of a vivid sensory imagination). The essential feature of experience is it feels a certain way  -that there is something that it is like to have it. We may refer to this feature of an experience as its ‘character’.
 Another core feature of the sorts of experiences with which this may be of a concern, is that they have representational ‘content’. (Unless otherwise indicated, ‘experience’ will be reserved for their ‘contentual representations’.) The most obvious cases of experiences with content are sense experiences of the kind normally involved in perception. We may describe such experiences by mentioning their sensory modalities ad their contents, e.g., a gustatory experience (modality) of chocolate ice cream (content), but do so more commonly by means of perceptual verbs combined with noun phrases specifying their contents, as in ‘Macbeth saw a dagger’. This is, however, ambiguous between the perceptual claim ‘There was a (material) dagger in the world that Macbeth perceived visually’ and ‘Macbeth had a visual experience of a dagger’ (the reading with which we are concerned, as it is afforded by our imagination, or perhaps, experiencing mentally hallucinogenic imagery).
 As in the case of other mental states and events with content, it is important to distinguish between the properties that and experience ‘represents’ and the properties that it ‘possesses’. To talk of the representational properties of an experience is to say something about its content, not to attribute those properties to the experience itself. Like every other experience, a visual; experience of a non-shaped square, of which is a mental event, and it is therefore not itself irregular or is it square, even though it represents those properties. It is, perhaps, fleeting, pleasant or unusual, even though it does not represent those properties. An experience may represent a property that it possesses, and it may even do so in virtue of a rapidly changing (complex) experience representing something as changing rapidly.  However, this is the exception and not the rule.
 Which properties can be [directly] represented in sense experience is subject to debate. Traditionalists include only properties whose presence could not be doubted by a subject having appropriate experiences, e.g., colour and shape in the case of visual experience, and apparent shape, surface texture, hardness, etc., in the case of tactile experience. This view is natural to anyone who has an egocentric, Cartesian perspective in epistemology, and who wishes for pure data in experiences to serve as logically certain foundations for knowledge, especially to the immediate objects of perceptual awareness in or of sense-data, such categorized of colour patches and shapes, which are usually supposed distinct from surfaces of physical objectivity. Qualities of sense-data are supposed to be distinct from physical qualities because their perception is more relative to conditions, more certain, and more immediate, and because sense-data is private and cannot appear other than they are they are objects that change in our perceptual field when conditions of perception change.  Physical objects remain constant.
 Others who do not think that this wish can be satisfied, and who are more impressed with the role of experience in providing animisms with ecologically significant information about the world around them, claim that sense experiences represent properties, characteristic and kinds that are much richer and much more wide-ranging than the traditional sensory qualities. We do not see only colours and shapes, they tell ‘us’, but also earth, water, men, women and fire: We do not smell only odours, but also food and filth. There is no space here to examine the factors relevantly responsible to their choice of situational alternatives. Yet, this suggests that character and content are not really distinct, and there is a close tie between them. For one thing, the relative complexity of the character of sense experience places limitations upon its possible content, e.g., a tactile experience of something touching one’s left ear is just too simple to carry the same amount of content as typically convincing to an every day, visual experience. Moreover, the content of a sense experience of a given character depends on the normal causes of appropriately similar experiences, e.g., the sort of gustatory experience that we have when eating chocolate would be not represented as chocolate unless it was normally caused by chocolate. Granting a contingent ties between the character of an experience and its possible causal origins, once, again follows that its possible content is limited by its character.
 Character and content are none the less irreducibly different, for the following reasons. (a) There are experiences that completely lack content, e.g., certain bodily pleasures. (b) Not every aspect of the character of an experience with content is relevant to that content, e.g., the unpleasantness of an aural experience of chalk squeaking on a board may have no representational significance. © Experiences in different modalities may overlap in content without a parallel overlap in character, e.g., visual and tactile experiences of circularity feel completely different. (d) The content of an experience with a given character may vary according to the background of the subject, e.g., a certain content ‘singing bird’ only after the subject has learned something about birds.
 According to the act/object analysis of experience (which is a special case of the act/object analysis of consciousness), every experience involves an object of experience even if it has no material object. Two main lines of argument may be offered in support of this view, one ‘phenomenological’ and the other ‘semantic’.
 In an outline, the phenomenological argument is as follows. Whenever we have an experience, even if nothing beyond the experience answers to it, we seem to be presented with something through the experience (which is itself diaphanous). The object of the experience is whatever is so presented to ‘us’-is that it is an individual thing, an event, or a state of affairs.
 The semantic argument is that objects of experience are required in order to make sense of certain features of our talk about experience, including, in particular, the following. (i) Simple attributions of experience, e.g., ‘Rod is experiencing an oddity that is not really square but in appearance it seems more than likely a square’, this seems to be relational. (ii) We appear to refer to objects of experience and to attribute properties to them, e.g., ‘The after-image that John experienced was certainly odd’. (iii) We appear to quantify ov er objects of experience, e.g., ‘Macbeth saw something that his wife did not see’.
 The act/object analysis faces several problems concerning the status of objects of experiences. Currently the most common view is that they are sense-data  -private mental entities that actually posses the traditional sensory qualities represented by the experiences of which they are the objects. But the very idea of an essentially private entity is suspect. Moreover, since an experience may apparently represent something as having a determinable property, e.g., redness, without representing it as having any subordinate determinate property, e.g., any specific shade of red, a sense-datum may actually have a determinate property subordinate to it. Even more disturbing is that sense-data may have contradictory properties, since experiences can have contradictory contents. A case in point is the waterfall illusion: If you stare at a waterfall for a minute and then immediately fixate on a nearby rock, you are likely to have an experience of the rock’s moving upward while it remains in the same place. The sense-data theorist must either deny that there are such experiences or admit contradictory objects.
 These problems can be avoided by treating objects of experience as properties. This, however, fails to do justice to the appearances, for experience seems not to present ‘us’ with properties embodied in individuals. The view that objects of experience is Meinongian objects accommodate this point. It is also attractive in as far as (1) it allows experiences to represent properties other than traditional sensory qualities, and (2) it allows for the identification of objects of experience and objects of perception in the case of experiences that constitute perception.
 According to the act/object analysis of experience, every experience with content involves an object of experience to which the subject is related by an act of awareness (the event of experiencing that object). This is meant to apply not only to perceptions, which have material objects (whatever is perceived), but also to experiences like hallucinations and dream experiences, which do not. Such experiences none the less appear to represent something, and their objects are supposed to be whatever it is that they represent. Act/object theorists may differ on the nature of objects of experience, which have been treated as properties. Meinongian objects (which may not exist or have any form of being), and, more commonly private mental entities with sensory qualities. (The term ‘sense-data’ is now usually applied to the latter, but has also been used as a general term for objects of sense experiences, as in the work of G. E. Moore) Act/object theorists may also differ on the relationship between objects of experience and objects of perception. In terms of perception (of which we are ‘indirectly aware’) are always distinct from objects of experience (of which we are ‘directly aware’). Meinongian, however, may treat objects of perception as existing objects of experience. But sense-datum theorists must either deny that there are such experiences or admit contradictory objects. Still, most philosophers will feel that the Meinongian’s acceptance of impossible objects is too high a price to pay for these benefits.
 A general problem for the act/object analysis is that the question of whether two subjects are experiencing one and the same thing (as opposed to having exactly similar experiences) appears to have an answer only on the assumption that the experiences concerned are perceptions with material objects. But in terms of the act/object analysis the question must have an answer even when this condition is not satisfied. (The answer is always negative on the sense-datum theory; it could be positive on other versions of the act/object analysis, depending on the facts of the case.)
 In view of the above problems, the case for the act/object analysis should be reassessed. The phenomenological argument is not, on reflection, convincing, for it is easy enough to grant that any experience appears to present ‘us’ with an object without accepting that it actually does. The semantic argument is more impressive, but is none the less answerable. The seemingly relational structure of attributions of experience is a challenge dealt with below in connection with the adverbial theory. Apparent reference to and quantification over objects of experience can be handled by analysing them as reference to experiences themselves and quantification over experiences tacitly typed according to content. Thus, ‘The after-image that John experienced was colourfully appealing’ becomes ‘John’s after-image experience was an experience of colour’, and ‘Macbeth saw something that his wife did not see’ becomes ‘Macbeth had a visual experience that his wife did not have’.
 Pure cognitivism attempts to avoid the problems facing the act/object analysis by reducing experiences to cognitive events or associated disposition, e.g., Susy’s experience of a rough surface beneath her hand might be identified with the event of her acquiring the belief that there is a rough surface beneath her hand, or, if she does not acquire this belief, with a disposition to acquire it that has somehow been blocked.
 This position has attractions. It does full justice to the cognitive contents of experience, and to the important role of experience as a source of belief acquisition. It would also help clear the way for a naturalistic theory of mind, since there seems to be some prospect of a physicalist/functionalist account of belief and other intentional states. But pure cognitivism is completely undermined by its failure to accommodate the fact that experiences have a felt character that cannot be reduced to their content, as aforementioned.
 The adverbial theory is an attempt to undermine the act/object analysis by suggesting a semantic account of attributions of experience that does not require objects of experience. Unfortunately, the oddities of explicit adverbializations of such statements have driven off potential supporters of the theory. Furthermore, the theory remains largely undeveloped, and attempted refutations have traded on this. It may, however, be founded on sound basis intuitions, and there is reason to believe that an effective development of the theory (which is merely hinting at) is possible.
 The relevant intuitions are (1) that when we say that someone is experiencing ‘an A’, or has an experience ‘of an A’, we are using this content-expression to specify the type of thing that the experience is especially apt to fit, (2) that doing this is a matter of saying something about the experience itself (and maybe about the normal causes of like experiences), and (3) that it is no-good of reasons to posit of its position to presuppose that of any involvements, is that its descriptions of an object in which the experience is. Thus the effective role of the content-expression in a statement of experience is to modify the verb it compliments, not to introduce a special type of object.
 Perhaps, the most important criticism of the adverbial theory is the ‘many property problem’, according to which the theory does not have the resources to distinguish between, e.g.,
 (1)   Frank has an experience of a brown triangle
and:
 (2)   Frank has an experience of brown and an experience of a triangle.
Which is entailed by (1) but does not entail it. The act/object analysis can easily accommodate the difference between (1) and (2) by claiming that the truth of (1) requires a single object of experience that is both brown and triangular, while that of the (2) allows for the possibility of two objects of experience, one brown and the other triangular, however, (1) is equivalent to:
 (1*)   Frank has an experience of something’s being both brown and triangular.
And (2) is equivalent to:
 (2*)   Frank has an experience of something’s being brown and an experience of something’s being triangular,
and the difference between these can be explained quite simply in terms of logical scope without invoking objects of experience. The Adverbialists may use this to answer the many-property problem by arguing that the phrase ‘a brown triangle’ in (1) does the same work as the clause ‘something’s being both brown and triangular’ in (1*). This is perfectly compatible with the view that it also has the ‘adverbial’ function of modifying the verb ‘has an experience of’, for it specifies the experience more narrowly just by giving a necessary condition for the satisfaction of the experience (the condition being that there are something both brown and triangular before Frank).
 A final position that should be mentioned is the state theory, according to which a sense experience of an ‘A’ is an occurrent, non-relational state of the kind that the subject would be in when perceiving an ‘A’. Suitably qualified, this claim is no doubt true, but its significance is subject to debate. Here it is enough to remark that the claim is compatible with both pure cognitivism and the adverbial theory, and that state theorists are probably best advised to adopt adverbials as a means of developing their intuitions.
 Yet, clarifying sense-data, if taken literally, is that which is given by the senses. But in response to the question of what exactly is so given, sense-data theories posit private showings in the consciousness of the subject. In the case of vision this would be a kind of inner picture show which itself only indirectly represents aspects of the external world that has in and of itself a worldly representation. The view has been widely rejected as implying that we really only see extremely thin coloured pictures interposed between our mind’s eye and reality. Modern approaches to perception tend to reject any conception of the eye as a camera or lense, simply responsible for producing private images, and stress the active life of the subject in and of the world, as the determinant of experience.
 Nevertheless, the argument from illusion is of itself the usually intended directive to establish that certain familiar facts about illusion disprove the theory of perception called naïevity or direct realism. There are, however, many different versions of the argument that must be distinguished carefully. Some of these distinctions centre on the content of the premises (the nature of the appeal to illusion); others centre on the interpretation of the conclusion (the kind of direct realism under attack). Let ‘us’ set about by distinguishing the importantly different versions of direct realism which one might take to be vulnerable to familiar facts about the possibility of perceptual illusion.
 A crude statement of direct realism might go as follows. In perception, we sometimes directly perceive physical objects and their properties, we do not always perceive physical objects by perceiving something ‘else’, e.g., a sense-datum. There are, however, difficulties with this formulation of the view, as for one thing a great many philosophers who are ‘not’ direct realists would admit that it is a mistake to describe people as actually ‘perceiving’ something other than a physical object. In particular, such philosophers might admit, we should never say that we perceive sense-data. To talk that way would be to suppose that we should model our understanding of our relationship to sense-data on our understanding of the ordinary use of perceptual verbs as they describe our relation to and of the physical world, and that is the last thing paradigm sense-datum theorists should want. At least, many of the philosophers who objected to direct realism would prefer to express in what they were of objecting too in terms of a technical (and philosophically controversial) concept such as ‘acquaintance’. Using such a notion, we could define direct realism this way: In ‘veridical’ experience we are directly acquainted with parts, e.g., surfaces, or constituents of physical objects. A less cautious verison of the view might drop the reference to veridical experience and claim simply that in all experience we are directly acquainted with parts or constituents of physical objects. The expressions ‘knowledge by acquaintance’ and ‘knowledge by description’, and the distinction they mark between knowing ‘things’ and knowing ‘about’ things, are generally associated with Bertrand Russell (1872-1970), that scientific philosophy required analysing many objects of belief as ‘logical constructions’ or ‘logical fictions’, and the programme of analysis that this inaugurated dominated the subsequent philosophy of logical atomism, and then of other philosophers, Russell’s “The Analysis of Mind,” the mind itself is treated in a fashion reminiscent of Hume, as no more than the collection of neutral perceptions or sense-data that make up the flux of conscious experience, and that looked at another way that also was to make up the external world (neutral monism), but “An Inquiry into Meaning and Truth” (1940) represents a more empirical approach to the problem. Yet, philosophers have perennially investigated this and related distinctions using varying terminology.
 Distinction in our ways of knowing things, highlighted by Russell and forming a central element in his philosophy after the discovery of the theory of ‘definite descriptions’. A thing is known by acquaintance when there is direct experience of it. It is known by description if it can only be described as a thing with such-and-such properties. In everyday parlance, I might know my spouse and children by acquaintance, but know someone as ‘the first person born at sea’ only by description. However, for a variety of reasons Russell shrinks the area of things that can be known by acquaintance until eventually only current experience, perhaps my own self, and certain universals or meanings qualify anything else is known only as the thing that has such-and-such qualities.
 Because one can interpret the relation of acquaintance or awareness as one that is not ‘epistemic’, i.e., not a kind of propositional knowledge, it is important to distinguish the above aforementioned views read as ontological theses from a view one might call ‘epistemological direct realism? In perception we are, on at least some occasions, non-inferentially justified in believing a proposition asserting the existence of a physical object. Since it is that these objects exist independently of any mind that might perceive them, and so it thereby rules out all forms of idealism and phenomenalism, which hold that there are no such independently existing objects. Its being to ‘direct’ realism rules out those views defended under the cubic of ‘critical naive realism’, or ‘representational realism’, in which there is some non-physical intermediary  -usually called a ‘sense-datum’ or a ‘sense impression’  -that must first be perceived or experienced in order to perceive the object that exists independently of this perception. Often the distinction between direct realism and other theories of perception is explained more fully in terms of what is ‘immediately’ perceived, than ‘mediately’ perceived. What relevance does illusion have for these two forms of direct realism?
 The fundamental premise of the arguments is from illusion seems to be the theses that things can appear to be other than they are. Thus, for example, straight sticks when immerged in water looks bent, a penny when viewed from certain perspective appears as an illusory spatial elliptic circularity, when something that is yellow when place under red fluorescent light looks red. In all of these cases, one version of the argument goes, it is implausible to maintain that what we are directly acquainted with is the real nature of the object in question. Indeed, it is hard to see how we can be said to be aware of the really physical object at all. In the above illusions the things we were aware of actually were bent, elliptical and red, respectively. But, by hypothesis, the really physical objects lacked these properties. Thus, we were not aware of the substantial reality of been real as a  physical objects or theory.
 So far, if the argument is relevant to any of the direct realisms distinguished above, it seems relevant only to the claim that in all sense experience we are directly acquainted with parts or constituents of physical objects. After all, even if in illusion we are not acquainted with physical objects, but their surfaces, or their constituents, why should we conclude anything about the hidden nature of our relations to the physical world in veridical experience?
 We are supposed to discover the answer to this question by noticing the similarities between illusory experience and veridical experience and by reflecting on what makes illusion possible at all. Illusion can occur because the nature of the illusory experience is determined, not just by the nature of the object perceived, but also by other conditions, both external and internal as becoming of an inner or as the outer experience. But all of our sensations are subject to these causal influences and it would be gratuitous and arbitrary to select from indefinitely of many and subtly different perceptual experiences some special ones those that get ‘us’ in touch with the ‘real’ nature of the physical world and its surrounding surfaces. Red fluorescent light affects the way thing’s look, but so does sunlight. Water reflects light, but so does air. We have no unmediated access to the external world.
 Still, why should we consider that we are aware of something other than a physical object in experience? Why should we not conclude that to be aware of a physical object is just to be appeared to by that object in a certain way? In its best-known form the adverbial theory of something proposes that the grammatical object of a statement attributing an experience to someone be analysed as an adverb. For example,
 (A) Rod is experiencing a coloured square.
Is rewritten as?
 Rod is experiencing, (coloured square)-ly
This is presented as an alternative to the act/object analysis, according to which the truth of a statement like (A) requires the existence of an object of experience corresponding to its grammatical object. A commitment to t he explicit adverbializations of statements of experience is not, however, essential to adverbialism. The core of the theory consists, rather, in the denial of objects of experience (as opposed ti objects of perception) coupled with the view that the role of the grammatical object in a statement of experience is to characterize more fully te sort of experience that is being attributed to the subject. The claim, then, is that the grammatical object is functioning as a modifier and, in particular, as a modifier of a verb. If it as a special kind of adverb at the semantic level.
 At this point, it might be profitable to move from considering the possibility of illusion to considering the possibility of hallucination. Instead of comparing paradigmatic veridical perception with illusion, let ‘us’ compare it with complete hallucination. For any experiences or sequence of experiences we take to be veridical, we can imagine qualitatively indistinguishable experiences occurring as part of a hallucination. For those who like their philosophical arguments spiced with a touch of science, we can imagine that our brains were surreptitiously removed in the night, and unbeknown to ‘us’ are being stimulated by a neurophysiologist so as to produce the very sensations that we would normally associate with a trip to the Grand Canyon. Currently permit ‘us’ into appealing of what we are aware of in this complete hallucination that is obvious that we are not awaken to the sparking awareness of physical objects, their surfaces, or their constituents. Nor can we even construe the experience as one of an object’s appearing to ‘us’ in a certain way. It is after all a complete hallucination and the objects we take to exist before ‘us’ are simply not there. But if we compare hallucinatory experience with the qualitatively indistinguishable veridical experiences, should we most conclude that it would be ‘special’ to suppose that in veridical experience we are aware of something radically different from what we are aware of in hallucinatory experience? Again, it might help to reflect on our belief that the immediate cause of hallucinatory experience and veridical experience might be the very same brain event, and it is surely implausible to suppose that the effects of this same cause are radically different  -acquaintance with physical objects in the case of veridical experience: Something else in the case of hallucinatory experience.
 This version of the argument from hallucination would seem to address straightforwardly the ontological versions of direct realism. The argument is supposed to convince ‘us’ that the ontological analysis of sensation in both veridical and hallucinatory experience should give ‘us’ the same results, but in the hallucinatory case there is no plausible physical object, constituent of a physical object, or surface of a physical object with which additional premiss we would also get an argument against epistemological direct realism. That premiss is that in a vivid hallucinatory experience we might have precisely the same justification for believing (falsely) what we do about the physical world as we do in the analogous, phenomenological indistinguishable, veridical experience. But our justification for believing that there is a table before ‘us’ in the course of a vivid hallucination of a table are surely not non-inferential in character. It certainly is not, if non-inferential justifications are supposedly a consist but yet an unproblematic access to the fact that makes true our belief  -by hypothesis the table does not exist. But if the justification that hallucinatory experiences give ‘us’ the same as the justification we get from the parallel veridical experience, then we should not describe a veridical experience as giving ‘us non-inferential justification for believing in the existence of physical objects. In both cases we should say that we believe what we do about the physical world on the basis of what we know directly about the character of our experience.
 In this brief space, I can only sketch some of the objections that might be raised against arguments from illusion and hallucination. That being said, let us begin with a criticism that accepts most of the presuppositions of the arguments. Even if the possibility of hallucination establishes that in some experience we are not acquainted with constituents of physical objects, it is not clear that it establishes that we are never acquainted with a constituent of physical objects. Suppose, for example, that we decide that in both veridical and hallucinatory experience we are acquainted with sense-data. At least some philosophers have tried to identify physical objects with ‘bundles’ of actual and possible sense-data.
 To establish inductively that sensations are signs of physical objects one would have to observe a correlation between the occurrence of certain sensations and the existence of certain physical objects. But to observe such a correlation in order to establish a connection, one would need independent access to physical objects and, by hypothesis, this one cannot have. If one further adopts the verificationist’s stance that the ability to comprehend is parasitic on the ability to confirm, one can easily be driven to Hume’s conclusion:
 Let us chance our imagination to the heavens, or to the utmost limits of the universe, we never really advance a step beyond ourselves, nor can conceivable any kind of existence, but those perceptions, which have appear̀d in that narrow compass. This is the universe of the imagination, nor have we have any idea but what is there  Reduced. (Hume, 1739-40, pp. 67-8).
If one reaches such a conclusion but wants to maintain the intelligibility and verifiability of the assertion about the physical world, one can go either the idealistic or the phenomenalistic route.
 However, hallucinatory experiences on this view is non-veridical precisely because the sense-data one is acquainted with in hallucination do not bear the appropriate relations to other actual and possible sense-data. But if such a view were plausible one could agree that one is acquainted with the same kind of a thing in veridical and non-veridical experience but insists that there is still a sense in which in veridical experience one is acquainted with constituents of a physical object?
 A different sort of objection to the argument from illusion or hallucination concerns its use in drawing conclusions we have not stressed in the above discourses. I, have in mentioning this objection, may to underscore an important feature of the argument. At least some philosophers (Hume, for example) have stressed the rejection of direct realism on the road to an argument for general scepticism with respect to the physical world. Once one abandons epistemological; direct realisms, one has an uphill battle indicating how one can legitimately make the inferences from sensation to physical objects. But philosophers who appeal to the existence of illusion and hallucination to develop an argument for scepticism can be accused of having an epistemically self-defeating argument. One could justifiably infer sceptical conclusions from the existence of illusion and hallucination only if one justifiably believed that such experiences exist, but if one is justified in believing that illusion exists, one must be justified in believing at least, some facts about the physical world (for example, that straight sticks look bent in water). The key point to stress in relying to such arguments is, that strictly speaking, the philosophers in question need only appeal to the ‘possibility’ of a vivid illusion and hallucination. Although it would have been psychologically more difficult to come up with arguments from illusion and hallucination if we did not believe that we actually had such experiences, I take it that most philosophers would argue that the possibility of such experiences is enough to establish difficulties with direct realism. Indeed, if one looks carefully at the argument from hallucination discussed earlier, one sees that it nowhere makes any claims about actual cases of hallucinatory experience.
 Another reply to the attack on epistemological direct realism focuses on the implausibility of claiming that there is any process of ‘inference’ wrapped up in our beliefs about the world and its surrounding surfaces. Even if it is possible to give a phenomenological description of the subjective character of sensation, it requires a special sort of skill that most people lack. Our perceptual beliefs about the physical world are surely direct, at least in the sense that they are unmediated by any sort of conscious inference from premisses describing something other than a physical object. The appropriate reply to this objection, however, is simply to acknowledge the relevant phenomenological fact and point out that from the perceptive of epistemologically direct realism, the philosopher is attacking a claim about the nature of our justification for believing propositions about the physical world. Such philosophers need carry out of any comment at all about the causal genesis of such beliefs.
 As mentioned that proponents of the argument from illusion and hallucination have often intended it to establish the existence of sense-data, and many philosophers have attacked the so-called sense-datum inference presupposed in some statements of the argument. When the stick looked bent, the penny looked elliptical and the yellow object looked red, the sense-datum theorist wanted to infer that there was something bent, elliptical and red, respectively. But such an inference is surely suspect. Usually, we do not infer that because something appears to have a certain property, that affairs that affecting something that has that property. When in saying that Jones looks like a doctor, I surely would not want anyone to infer that there must actually be someone there who is a doctor. In assessing this objection, it will be important to distinguish different uses words like ‘appears’ and ‘looks’. At least, sometimes to say that something looks ‘F’ way and the sense-datum inference from an F ‘appearance’ in this sense to an actual ‘F’ would be hopeless. However, it also seems that we use the ‘appears’/’looks’ terminology to describe the phenomenological character of our experience and the inference might be more plausible when the terms are used this way. Still, it does seem that the arguments from illusion and hallucination will not by themselves constitute strong evidence for sense-datum theory. Even if one concludes that there is something common to both the hallucination of a red thing and a veridical visual experience of a red thing, one need not describe a common constituent as awarenesses of something red. The adverbial theorist would prefer to construe the common experiential state as ‘being appeared too redly’, a technical description intended only to convey the idea that the state in question need not be analysed as relational in character. Those who opt for an adverbial theory of sensation need to make good the claim that their artificial adverbs can be given a sense that is not parasitic upon an understanding of the adjectives transformed into verbs. Still, other philosophers might try to reduce the common element in veridical and non-veridical experience to some kind of intentional state.  More like belief or judgement. The idea here is that the only thing common to the two experiences is the fact that in both I spontaneously takes there to be present an object of a certain kind.