Ryle claims that the notion that body and mind are two different entities is a logical mistake consisting in viewing the mind as publicly inaccessible, not witnessable by other observers, private (p.13): ‘The verbs, nouns and adjectives, with which in ordinary life we describe the wits, characters and higher-grade performances of the people with whom we have to do, are required to be construed as signifying special episodes in their secret histories … When someone is described as knowing, believing or guessing something, as hoping, dreading, intending or shirking something, as designing this or being amused at that, these verbs are supposed to denote the occurrence of specific modifications in his (to us) occult stream of consciousness. Only his own privileged access to this stream in direct awareness and introspection could provide authentic testimony that these mental-conduct words were correctly or incorrectly applied. The onlooker, be he teacher, critic, biographer or friend, can never assure himself that his comments have any vestige of truth. Yet it was just because we do in fact all know how to make such comments, make them with general correctness and correct them when they turn out to be confused or mistaken, that philosophers found it necessary to construct their theories of the nature and place of minds. Finding mental-conduct concepts being regularly and effectively used, they properly sought to fix their logical geography. But the logical geography officially recommended would entail that there could be no regular or effective use of these mental-conduct concepts in our description of, and prescription for, other people’s minds.’ (p. 17)
Having thus outlined ‘the official theory’, Ryle declares it to be a category-mistake: ‘It represents the facts of mental life as if they belonged to one logical type or category (or range of types or categories) when they actually belong to another.’ (p. 17) He explains what he means as follows: ‘When two terms belong to the same category, it is proper to construct conjunctive propositions embodying them. Thus a purchaser may say that he bought a left-hand glove and a right-hand glove and a pair of gloves. “She came home either in flood of tears and a sedan chair” is a well-known joke based on the absurdity of conjoining terms of different types. It would have been equally ridiculous to construct the disjunction: “She came home either in flood of tears or else in a sedan chair”. Now the dogma of the Ghost in the Machine does just this. It maintains that there exist both bodies and minds; that there occur physical processes and mental processes; that there are mechanical causes of corporeal movements and mental causes of corporeal movements. I shall argue that these and other analogous conjunctions are absurd … I am not denying that there occur mental processes … But I am saying that the phrase ‘there occur mental processes’, does not mean the same sort of thing as ‘there occur physical processes’, and, therefore, that it makes no sense to conjoin or disjoin the two.’ (p.23)
The alleged absurdity of conjoining or disjoining the two allows Ryle to avoid difficulties in which the ‘official theory’ was embroiled, such as the following: ‘The actual transactions between the episodes of the private history and those of the public history remain mysterious … they can be inspected neither by introspection nor by laboratory experiment. They are theoretical shuttlecocks which are forever being bandied from the physiologist back to the psychologist and from the psychologist back to the physiologist.’ (p.14) ‘There was from the beginning felt to be a major theoretical difficulty in explaining how minds can influence and be influenced by bodies. How can a mental process, such as willing, cause spatial movements like the movements of the tongue? How can a physical change in the optic nerve have among its effects a mind’s perception of a flash of light? This notorious crux by itself shows the logical mould into which Descartes pressed his theory of the mind.’ (p. 21)
The philosophical consequences of avoiding the logical ‘absurdity’ of conjoining or disjoining of mental and physical processes, as Ryle puts it, are colossal: ‘First, the hallowed contrast between Mind and Matter will be dissipated, but dissipated not by either of the equally hallowed absorptions of Mind by Matter or of Matter by Mind, but in quite a different way. For the seeming contrast of the two will be shown to be as illegitimate as would be the contrast of ‘she came home in a flood of tears’ and ‘she came home in a sedan chair’. The belief that there is a polar opposition between Mind and Matter is the belief that they are terms of the same logical type.’ (p. 23)
I rack my brain in vain trying to understand what Ryle means when he says that ‘the belief that there is a polar opposition between Mind and Matter is the belief that they are terms of the same logical type’, and I cannot understand how can this opposition be dissipated when one realises that Mind and Matter are not of the same logical type. I cannot understand in what way my maintaining that there exist both bodies and minds; that there occur physical processes and mental processes; that there are mechanical causes of corporeal movements and mental causes of corporeal movements can be viewed as wrong in the light of the absurdity of conjoining terms of different types such as “She came home either in flood of tears and a sedan chair”.
Perhaps it might help if I bring in one of the rare passages where Ryle mentions a physicist and a physiologist: ‘When a person talks sense aloud, ties knots, feints or sculpts, the actions which we witness are themselves the things which he is intelligently doing, though the concepts in terms of which the physicist or physiologist would describe his actions do not exhaust those which would be used by his pupils or his teachers in appraising their logic, style or technique. He is bodily active and he is mentally active, but he is not being synchronously active in two different ‘places’, or with two different ‘engines’. There is the one activity, but it is one susceptible of and requiring more than one kind of explanatory description.’ (p.50)
Ryle speaks here in fact of three kinds of explanatory description: 1/ The terms in which we describe these actions as we witness them, appraising their logic, style or technique. This is the kind of explanatory description with which he is himself preoccupied throughout his book, ‘observing the ways in which these concepts actually behave’ instead of construing them ‘as items in the descriptions of occult causes and effects’ (p. 113) He does not explain how the same actions can be described by 2/ a physicist and 3/ a physiologist, but he gives a clue to what he means: ‘there need be no physical or physiological differences between the descriptions of one man as gabbling and another talking sense, though the rhetorical and logical differences are enormous (l. c.).’ A physicist might agree that there need be no physical differences, but I cannot see a neurophysiologist agreeing that there need be no neurophysiological differences between the two.
To make this point, let me quote Roger Carpenter and Benjamin Reddi’s Neurophysiology: ‘On the one hand we have all the unspeakable wonders of our minds; on the other hand, when we open up the skull and peep inside all we see is a porridgy lump containing millions and millions of untidy neurons. The fundamental problem of neuroscience is that of linking these two scales together: can we trace the relationship between molecular and cellular mechanisms all the way to what was going on in Michelangelo’s head as he painted the Sistine Chapel?’ (5th edition, Hodder Arnold 2012, p. 9) With such aspirations, neurophysiology can hardly fail to aspire to registering in its terms the difference between gabbling and talking sense.
But here is a more important observation that I must make at this point. Although a physicist cannot register the difference between gabbling and talking sense in terms of his science, he can explain to us the physics of how speaking effects the air, of how this effect is propagated in the form of regular waves of pressure through the air, and of how it effects the ear drum of the listener. In this sense there is a correspondence between what we see and hear and what the physicists can tell us about it. This correspondence breaks down when neurophysiology steps in: the sound energy is transduced into nervous energy propagated by auditory pathways into the auditory cortex and the incident light is transformed into electrical changes sent by the optic nerve to the visual cortex in the brain. In the brain there is no sound and no light; since we hear sounds and see the world around us only thanks to and on the basis of the activity of our auditory and optical nerve cells and our auditory and visual cortex, the chemical and electrical activities in our auditory and optical nerve cells and in our auditory and visual cortex must be transformed into what we hear and what we see. Everything that we can hear and see is thus linked to and at the same time and by the same token separated from the outside world.
Let me turn back to Ryle: ‘No metaphysical Iron Curtain exists compelling us to be for ever absolute strangers to one another … Similarly no metaphysical looking-glass exists compelling us to be for ever disclosed and explained to ourselves (p. 173) … it was wrong from the start to contrast the common objects of everyone’s observation, like robins and cheeses, with the supposed peculiar objects of my privileged observation, namely my sensations, since sensations are not objects of observation at all. We do not, consequently, have to rig up one theatre, called ‘the outside world’, to house the common objects of anyone’s observation, and another, called ‘the mind’ to house the common objects of some monopoly observations. The antithesis between ‘public’ and ‘private’ was in part a misconstruction of the antithesis between objects which can be looked at, handled and tasted, on the one hand, and sensations which are had but not looked at, handled or tasted on the other.’ (p. 198)
Throughout The Concept of Mind, Ryle is preoccupied with debunking the separation between the ‘private’ and the ‘outside’ world. And in one respect he is perfectly right, for the world I see in front of my eyes is my mind in action. But the moment I realise this – thanks to neurophysiology – I begin to appreciate how essential it is for every human being to view the ‘outside world’ perceived by the mind as the world outside; this can be done only by virtue of the distinction between ‘private’ and ‘public’ domain within the framework of the mind.