The Primacy of the Scientific Image: A Prolegomenon

¶Is this the truth of the matter? Is the manifest image, subject, of course, to continual empirical and categorial refinements, the measure of what there really is? I do not think so. I have already indicated that of the three alternatives we are considering with respect to the comparative claims of the manifest and scientific images, the first, which, like a child, says 'both', is ruled out by a principle which I am not defending in this chapter, although it does stand in need of defence. The second alternative is the one I have just reformulated and rejected. I propose, therefore, to re-examine the case against the third alternative, the primacy of the scientific image. My strategy will be to argue that the difficulty, raised above, which seems to stand in the way of the identification of thought with cerebral processes, arises from the mistake of supposing that in self-awareness conceptual thinking presents itself to us in a qualitative guise. Sensations and images do, we shall see, present themselves to us in a qualitative character, a fact which accounts for the fact that they are stumbling blocks in the attempt to accept the scientific image as real. But one scarcely needs to point out these days that however intimately conceptual thinking is related to sensations and images, it cannot be equated with them, nor with complexes consisting of them.

¶It is no accident that when a novelist wishes to represent what is going on in the mind of a person, he does so by 'quoting' the person's thoughts as he might quote what a person says. For thoughts not only are the sort of things that find overt expression in language, we conceive of them as analogous to overt discourse. Thus, thoughts in the manifest image are conceived not in terms of their 'quality', but rather as inner 'goings-on' which are analogous to speech, and find their overt expression in speech -- though they can go on, of course, in the absence of this overt expression. It is no accident that one learns to think in the very process of learning to speak.

¶From this point of view one can appreciate the danger of misunderstanding which is contained in the term 'introspection'. For while there is, indeed, an analogy between the direct knowledge we have of our own thoughts and the perceptual knowledge we have of what is going on in the world around us, the analogy holds only in as much as both self-awareness and perceptual observation are basic forms of non-inferential knowledge. They differ, however, in that whereas in perceptual observation we know objects as being of a certain quality, in the direct knowledge we have of what we are thinking (e.g. I am thinking that it is cold outside) what we know non-inferentially is that something analogous to and properly expressed by the sentence, 'It is cold outside', is going on in me.

¶The point is an important one, for if the concept of a thought is the concept of an inner state analogous to speech, this leaves open the possibility that the inner state conceived in terms of this analogy is in its qualitative character a neurophysiological process. To draw a parallel: if I begin by thinking of the cause of a disease as a substance (to be called 'germs') which is analogous to a colony of rabbits, in that it is able to reproduce itself in geometrical proportion, but, unlike rabbits, imperceptible and, when present in sufficient number in the human body, able to cause the symptoms of disease, and to cause epidemics by spreading from person to person, there is no logical barrier to a subsequent identification of 'germs' thus conceived with the bacilli which microscopic investigation subsequently discovers.

¶But to point to the analogy between conceptual thinking and overt speech is only part of the story, for of equally decisive importance is the analogy between speech and what sophisticated computers can do, and finally, between computer circuits and conceivable patterns of neurophysiological organization. All of this is more or less speculative, less so now than even a few years ago. What interests the philosopher is the matter of principle; and here the first stage is decisive -- the recognition that the concept of a thought is a concept by analogy. Over and above this all we need is to recognize the force of Spinoza's statement: 'No one has thus far determined what the body can do nor no one has yet been taught by experience what the body can do merely by the laws of nature insofar as nature is considered merely as corporeal and extended.' (Ethics, Part Three, Prop. II (note)).

¶Another analogy which may be even more helpful is the following: suppose we are watching the telegraphic report of a chess game in a foreign country.

White	Black
P-K3	P-QB3

¶And suppose that we are sophisticated enough to know that chess pieces can be made of all shapes and sizes, that chess boards can be horizontal or vertical, indeed, distorted in all kinds of ways provided that they preserve certain topological features of the familiar board.

¶Then it is clear that while we will think of the players in the foreign country as moving kings, pawns, etc., castling and check-mating, our concepts of the pieces they are moving and the moving of them will be simply the concept of items and changes which play a role analogous to the pieces and moves which take place when we play chess. We know that the items must have some intrinsic quality (shape, size, etc.), but we think of these qualities as 'those which make possible a sequence of changes which are structurally similar to the changes which take place on our own chess boards'.

¶Thus our concept of 'what thoughts are' might, like our concept of what a castling is in chess, be abstract in the sense that it does not concern itself with the intrinsic character of thoughts, save as items which can occur in patterns of relationships Which are analogous to the way in which sentences are related to one another and to the contexts in which they are used.

¶Now if thoughts are items which are conceived in terms of the roles they play, then there is no barrier in principle to the identification of conceptual thinking with neurophysiological process. There would be no 'qualitative' remainder to be accounted for. The identification curiously enough, would be even more straightforward than the identification of the physical things in the manifest image with complex systems of physical particles. And in this key, if not decisive, respect, the respect in which both images are concerned with conceptual thinking (which is the distinctive trait of man), the manifest and scientific images could merge without clash in the synoptic view.

¶How does the situation stand in respect to sensation and feeling? Any attempt at identification of these items with neurophysiological process runs into a difficulty to which reference has already been made, and which we are now in a position to make more precise. This difficulty accounts for the fact that, with few exceptions, philosophers who have been prepared to identify conceptual thinking with neurophysiological process have not been prepared to make a similar identification in the case of sensation.

¶Before restating the problem let us note that curiously enough, there is more similarity between the two cases than is commonly recognized. For it turns out on reflection that just as conceptual thinking is construed in the manifest image by analogy with overt speech, so sensation is construed by analogy with its external cause, sensations being the states of persons which correspond, in their similarities and differences to the similarities and differences of the objects which, in standard conditions, bring them about. Let us assume that this is so. But if it is so, why not suppose that the inner-states which as sensations are conceived by analogy with their standard causes, are in propria persona complex neurophysiological episodes in the cerebral cortex? To do so would parallel the conclusion we Ye prepared to draw in the case of conceptual thinking.

¶Why do we feel that there would be something extremely odd, even absurd, about such a supposition? The key to the answer lies in noticing an important difference between identifying thoughts with neurophysiological states and identifying sensations with neurophysiological states. Whereas both thoughts and sensations are conceived by analogy with publicly observable items, in the former case the analogy concerns the role and hence leaves open the possibility that thoughts are radically different in their intrinsic character from the verbal behaviour by analogy with which they are conceived. But in the case of sensations, the analogy concerns the quality itself. Thus a 'blue and triangular sensation' is conceived by analogy with the blue and triangular (facing) surface of a physical object which, when looked at in daylight, is its cause. The crucial issue then is this: can we define, in the framework of neurophysiology, states which are sufficiently analogous in their intrinsic character to sensations to make identification plausible?

¶The answer seems clearly to be 'no'. This is not to say that neurophysiological states cannot be defined (in principle) which have a high degree of analogy to the sensations of the manifest image. That this can be done is an elementary fact in psycho-physics. The trouble is, rather, that the feature which we referred to as 'ultimate homogeneity', and which characterizes the perceptible qualities of things, e.g. their colour, seems to be essentially lacking in the domain of the definable states of nerves and their interactions. Putting it crudely, colour expanses in the manifest world consist of regions which are themselves colour expanses, and these consist in their turn of regions which are colour expanses, and so on; whereas the state of a group of neurons, though it has regions which are also states of groups of neurons, has ultimate regions which are not states of groups of neurons but rather states of single neurons. And the same is true if we move to the finer grained level of biochemical process.

¶Nor do we wish to say that the ultimate homogeneity of the sensation of a red rectangle is a matter of each physical particle in the appropriate region of the cortex having a colour; for whatever other difficulties such a view would involve, it doesn't make sense to say of the particles of physical theory that they are coloured. And the principle of reducibility, which we have accepted without argument, makes impossible the view that groups of particles can have properties which are not 'reducible to' the properties and relations of the members of the group.

¶It is worth noting that we have here a recurrence of the essential features of Eddington's 'two tables' problem -- the two tables being, in our terminology, the table of the manifest image and the table of the scientific image. There the problem was to 'fit together' the manifest table with the scientific table. Here the problem is to fit together the manifest sensation with its neurophysiological counterpart. And, interestingly enough, the problem in both cases is essentially the same: how to reconcile the ultimate homogeneity of the manifest image with the ultimate non-homogeneity of the system of scientific objects.

¶Now we are rejecting the view that the scientific image is a mere 'symbolic tool' for finding our way around in the manifest image; and we are accepting the view that the scientific account of the world is (in principle) the adequate image. Having, therefore, given the perceptible qualities of manifest objects their real locus in sensation we were confronted with the problem of choosing between dualism or identity with respect to the relation of conscious sensations to their analogues in the visual cortex, and the above argument seems to point clearly in the dualistic direction. The 'ultimate homogeneity' of perceptible qualities, which, among other things, prevented identifying the perceptible qualities of physical objects with complex properties of systems of physical particles, stands equally in the way of identifying, rather than correlating, conscious sensations with the complex neural processes with which they are obviously connected.

¶But such dualism is an unsatisfactory solution, because ex hypothesi sensations are essential to the explanation of how we come to construct the 'appearance' which is the manifest world. They are essential to the explanation of how there even seem to be coloured objects. But the scientific image presents itself as a closed system of explanation, and if the scientific image is interpreted as we have interpreted it up to this point the explanation will be in terms of the constructs of neurophysiology, which, according to the argument, do not involve the ultimate homogeneity, the appearance of which in the manifest image is to be explained.

¶We are confronted, therefore, by an antinomy, either, (a) the neurophysiological image is incomplete, i.e. and must be supplemented by new objects ('sense fields') which do have ultimate homogeneity and which somehow make their presence felt in the activity of the visual cortex as a system of physical particles; or, (b) the neurophysiological image is complete and the ultimate homogeneity of the sense qualities (and, hence, the sense qualities, themselves) is mere appearance in the very radical sense of not existing in the spatiotemporal world at all.

¶Is the situation irremediable? Does the assumption of the reality of the scientific image lead us to a dualism of particles and sense fields? of matter and 'consciousness'? If so, then, in view of the obviously intimate relation between sensation and conceptual thinking (for example, in perception), we must surely regress and take back the identification or conceptual thinking with neurophysiological process which seemed so plausible a moment ago. We could then Ague that although in the absence of other considerations it would be plausible to equate conceptual thinking with neurophysiological process, when the chips are all down, we must rather say that although conceptual thinking and neurophysiological process are each analogous to verbal behaviour as a public social phenomenon (the one by virtue of the very way in which the very notion of 'thinking' is formed; the other as a scientifically ascertained matter of fact), they are also merely analogous to one another and cannot be identified. If so, the manifest and the scientific conception of both sensations and conceptual thinking would fit into the synoptic view as parallel processes, a dualism which could only be avoided by interpreting the scientific image as a whole as a 'symbolic device' for coping with the world as it presents itself to us in the manifest image.

¶Is there any alternative? As long as the ultimate constituents of the scientific image are particles forming ever more complex systems of particles, we are inevitably confronted by the above choice. But the scientific image is not yet complete; we have not yet penetrated all the secrets of nature. And if it should turn out that particles instead of being the primitive entities of the scientific image could be treated as singularities in a space-time continuum which could be conceptually 'cut up' without significant loss -- in inorganic contexts, at least -- into interacting particles, then we would not be confronted at the level of neurophysiology with the problem of understanding the relation of sensory consciousness (with its ultimate homogeneity) to systems of particles. Rather, we would have the alternative of saying that although for many purposes the central nervous system can be construed without loss as a complex system of physical particles, when it comes to an adequate understanding of the relation of sensory consciousness to neurophysiological process, we must penetrate to the non-particulate foundation of the particulate image, and recognize that in this non-particulate image the qualities of sense are a dimension of natural process which occurs only in connection with those complex physical processes which, when 'cut-up' into particles in terms of those features which are the least common denominators of physical process -- present in inorganic as well as organic processes alike -- become the complex system of particles which, in the current scientific image, is the central nervous system.