Gogolian brains ...

'The physicist says: I find everywhere bodies and the motions of bodies only, no sensations; sensations, therefore, must be something entirely different from the physical objects I deal with. The psychologist accepts the second portion of this declaration. For him, as is proper, sensations are the primary data. But to these there corresponds a mysterious physical something which, conformably with the prepossession, must be quite different from sensations. But what is it that is really the mysterious thing? Is it the Physis or the Psyche? Or perhaps both? It would almost appear so, as it is now the one and now the other that appears unattainable and involved in impenetrable obscurity. Or are we here being led around in a circle by some evil spirit?'
—Ernst Mach (The Analysis of Sensations and the Relation of the Physical to the Psychical, p. 45)

Energumen Mach

Cartesianism never lasts long qua dualism. The qualitative-quantitative conjuct is too unhappy for that. But qua monism, breaking up into an either/or disjunct, it can be more longevous. So if you're a Cartesian, a concretizer of abstractions, it's better to be single than in a relationship. But why be a Cartesian at all? Why let oneself be led around in circles by that spirit which so troubled Mssr. Descartes? Consider Herr Mach, who wrote that coming to terms with the qualia-quanta duoverse was his greatest intellectual struggle. For all his struggling, he could not altogether dispossess himself of the dualising spirit. And in the end his was a species of half-Cartesian monism, privileging the qualitative half of Descartes' dualism, for (within Cartesianism) the quantaverse supervenes on the qualiaverse. Thus Mach: 'For me [psychologico-experiential phenomena] are immediately and indubitably given, and for me they can never be volitalized away by considerations which ultimately are always based on their existence' (ibid.). Just so. Contrariwise, today's neuroscientists privilege the quantitative half of Descartes' dualism. They accept materiality as defined by Descartes and reject mentality as defined by Descartes. They're a species of half-Cartesian monist, then, though they apply Descartes' dualistic grammar to their monism. That is, whereas Descartes had two substances and a logical grammar built therefor, today's neuroscientists have one of Descartes' two substances to which they apply his built-for-two grammar. (What could possibly go wrong?)

Remember that for whole-Cartesian dualists (and for half-Cartesian monists of the qualitative-experiential division) the mind is the primary subject of experience, and thus experience is solipsistically privatized. But for half-Cartesian monists of the quantitative-nonexperiential division the brain is the primary subject of experience, and thus, again, experience is solipsistically privatized (being inskulled). Ostensibly, half-Cartesians eliminate the interaction problem. However, in the logical grammar of contemporary neuroscience the brain is a substance (or is at least substantial). And so whereas past generations of neuroscientists had a mind-body dualism, the present generation has a brain-body dualism.

A brain called Crick, hiding behind a face

Ascribing psychologico-experiential concepts (thinking, knowing, learning, feeling, trusting, believing, remembering, understanding, reasoning, interpreting, hypothesizing ……) to the brain (and even to parts thereof) is everywhere in the literature, from academic journals of neuroscience to pop-science presentations. For example, Colin Blakemore tells us that 'neurons have knowledge,' that they 'present arguments to the brain … on which the brain constructs its hypothesis' (Mechanics of the Mind, p. 91); Joseph LeDoux tells us that it's 'possible for your brain to know that something is good or bad before it knows exactly what it is' (The Emotional Brain, p. 69); and Francis Crick tells us that:

'What you see is not what is really there, it is what your brain believes there … Your brain makes the best interpretation it can according to its previous experience and the limited and ambiguous information provided by your eyes … The brain combines the information provided by many distinct features of the visual scene (aspects of shape, colour, movement, etc.) and settles on the most plausible interpretation of all these various clues taken together …' (The Astonishing Hypothesis, pp. 30, 32.)

An independent individual

Etc., etc. However, a brain is an organ, not an organism. It is a part of an animal, not the whole thereof. And the proper subjects of experience are whole animate beings, not their organs or parts: totum est partibus suis prius. It is the mouse that runs from the cat, not the murine brain that runs from the feline brain. (Logically, how can that which has no legs run?) To be sure, when a cat sees, hears, and otherwise perceives a mouse, there are micro-happenings happening intercranially. And it's the neuroscientist's job to investigate these, to find efficient-causal correlates of perception (e.g.), which (as such) are empirico-inductive 'symptoms' thereof, not logico-conceptual criteria therefor. Without brains in their skulls, cats couldn't perceive mice. (Without brains, they'd be dead.) But it is not their brains that perceive. In Gogol's fantastical story The Nose, a nose leaves its faceplace and cavorts about Petersburg in civil-service uniform, disdainful of the man, Major Kovalyov, whose nose he was.

'How am I to approach him?' thought Kovalyov. One can see by everything—from his uniform, from his hat—that he is a civil councillor. The devil only knows how to do it!'
     He began by coughing at his side; but the nose never changed his position for a minute.
     'Sir,' said Kovalyov, inwardly forcing himself to speak confidently. 'Sir …'
     'What do you want?' answered the nose, turning round.
'It seems … strange to me, sir … You ought to know your proper place, and all at once I find you, where? … You will admit …'
     'Excuse me, I cannot understand what you are talking about. Explain …'
     'How am I to explain to him?' thought Kovalyov, and plucking up his courage he began: 'Of course I … I am a major, by the way. For me to go about without a nose you must admit is improper. An old woman selling peeled oranges on Voskresensky Bridge may sit there without a nose; but having prospects of obtaining … and being besides acquainted with a great many ladies in the families of Tchehtarev the civil councillor and others … You can judge for yourself … I don't know, sir (at this point Major Kovalyov shrugged his shoulders) … excuse me … if you look at the matter in accordance with the principles of duty and honour … you can understand of yourself …'
     'I don't understand a word,' said the nose. 'Explain it more satisfactorily.'
     'Sir,' said Kovalyov, with a sense of his own dignity, 'I don't know how to understand your words. The matter appears to me perfectly obvious … either you wish … Why, you are my own nose!'
     The nose looked at the major and his eyebrows slightly quivered.
     'You are mistaken, sir, I am an independent individual. Moreover, there can be no sort of close relations between us. I see, sir, from the buttons of your uniform, you must be serving in a different department.' Saying this the nose turned away.

Here an organ (of smell) becomes an organism, a component part becomes a standalone whole. (Cf. Krzhizhanovsky's story The Runaway Fingers.) The miswandered nose speaks, locomotes, wears a plumed hat and chamois-leather breeches. If brains were like Gogolian noses—speaking, locomoting, wearing hats and breeches—then we could say that brains see, hear, speak, think; but, no, brains aren't like that. We know what it means to say that a man dressed for the weather, went for a walk, smiled warmly at passersby, stopped at a coffee shop. But what does it mean to say that a brain dressed for the weather, went for a walk, smiled warmly at passersby, stopped at a coffee shop? If taken literally, these are nonsensical forms of words that say nothing. So, then, are neuroscientists speaking not qua scientists but qua poets, using metonymy, synecdoche, and suchlike? (Is 'my brain perceives …' a metonymical expression like 'my ears hear …'?) Or are all of the psychologico-experiential terms that they use no more than homonyms, such that when they say the brain (e.g.) believes, they mean that the brain '☆#✂✗◉'? Alas, the literature will not support either exegesis. Contextually, it is patent that the propounded explanations presuppose the standard meanings of the non-technical terms in question, meanings determined by rule-governed use.

Another independent individual

Reading neuroscientific texts can be a laborious exercise. For there are so many metaphors to deliteralise, abstractions to deconcretise, misdescriptions to redescribe, misascriptions to reascribe, misconceptions to reconceive, and so on. The scientific data are interred somewhere beneath all of this, and who knows if it will be worth the labour to disinter them. (Will there be anything left over?) Take some examples on hemispheric commissurotomy, referring to well-known work on the subject by Roger Sperry (1913-1994) and Michael Gazzaniga (1939-present). We'll start with The Journal of Neuroscience (2000, Vol. 20):

'Gazzaniga and Metcalfe et al have hypothesized the existence of an interpreter that plays the role of trying to make sense out of the information that it confronts, in other words, generating causal hypotheses. Using split-brain patients, Gazzaniga provided evidence that this interpreter is located in the left hemisphere in most individuals. The simultaneous concept test provides an example of the function of the interpreter. In this task, a split-brain patient is shown a picture exclusively to the left hemisphere (e.g., a chicken) and another picture exclusively to the right hemisphere (e.g., a snow scene). The patient is then given an array of pictures and asked to point to a picture associated with the presented pictures. In the above example, the left hemisphere chose a chicken claw, and the right hemisphere chose a shovel. When asked to explain the choices, the patient responded, "Oh, that’s simple. The chicken claw goes with the chicken, and you need a shovel to clean out the chicken shed." The right hemisphere is unable to produce speech, so it cannot explain its selection. The left hemisphere is unaware of the picture that the right hemisphere is responding to (i.e., the snow scene), so it must generate its own interpretation of why the left hand pointed to a shovel. The left hemisphere, observing the actions of the left hand and right brain, interprets those actions within the context of what it knows (i.e., a chicken claw) and generates an explanation for the shovel that is consistent with its knowledge.'

In the Brain Research Bulletin (1999, Vol. 50):

'Through past millennia, and for half of the present century, the existence of the two huge cerebral hemispheres in man passed with only an occasional puzzle as to what might transpire with each individually, and the nature of the interchange between them, if any … With the guiding genius of Sperry, studies on the ensuing series of patients has forever changed the way the mind is viewed as a product of the brain; indeed, two brains, the two hemispheres, each endowed with human thought and emotion, separable, but normally uncannily intertwined via the dense network of callosal fibers, negotiating the interplay between them. Hemispherectomy confirms the humanity of each, and neuroimaging now shows that in normal life each hemisphere is a lively participant concurrently in most mental processes so far examined. Deep questions still far outpace the answers … Recognition of the fact that the two human hemispheres are, potentially, two separable mental entities will reverberate at all levels of society across the coming centuries, redefining the nature of humanity, and humanity’s relation with nature.'

And as for Crick (The Astonishing Hypothesis, p. 170):

'When the callosum is cut, the left hemisphere sees only the right half of the visual field … Both hemispheres can hear what is being said … One half of the brain appears to be almost totally ignorant of what the other half saw.'

My, my. Were you counting? One, two, three subjects of experience, three independent Gogolian individuals: the patient, the left hemisphere, and the right hemisphere. Whence the surplus? We had only one subject to begin with. Ah, but Gazzaniga had written that right hemispheres 'are able to make judgments of grammaticality'—[aside] would that Gazzaniga were able to make judgements of grammaticality—that left hemispheres 'possesses a uniquely human capacity to interpret behaviour and to construct theories about the relationships between perceived events and feelings' (Neuron, 1995, Vol. 14). And our one was thrice multiplied. (And why stop at three? Neurons have knowledge, too, and scientists say there are 100,000,000,000 of them in a brain. We're all Legion.)

Yes, split-brain experiments gives us pause, insofar as contradictory criteria are present (cf. blindsight phenomena), but there's no need whatsoever to describe the experiments in the style of H.C. Andersen. And, again, the fallacies here are philosophical, not scientific; they're logico-conceptual, not empirico-factual. That brains have a 'capacity to acquire knowledge, to abstract and to construct ideals' (Semir Zeki, 'Splendours and Miseries of the Brain,' Philosophical Transactions of the Royal Society, p. 2054) is a proposition that scientists qua scientists can neither confirm nor disconfirm. For it's not possibly true or false as a matter of fact; it's a nonsensical, category-mistaken pseudo-sentence (and an example of what P.M.S. Hacker calls the mereological fallacy).

We are long overdue for a metaphysical regime change. Meantime, so long as we are beholden to Descartes, our confusion, bafflement, and mystification will persist. So long as we are beholden, it will perforce be the case that:

Tyndall

'The passage from the physics of the brain to the corresponding facts of consciousness is unthinkable. Granted that a definite thought, and a definite molecular action in the brain occur simultaneously, we do not possess the intellectual organ, nor apparently any rudiment of the organ, which would enable us to pass by a process of reasoning from the one phenomenon to the other. They appear together but we do not know why. Were our minds and senses so expanded, strengthened and illuminated as to enable us to see and feel the very molecules of the brain, were we capable of following all their motions, all their groupings, all their electric discharges, if such there be, and were we intimately acquainted with the corresponding states of thought and feeling, we should be as far as ever from the solution of the problem. How are these physical processes connected with the facts of consciousness? The chasm between the two classes of phenomena would still remain intellectually impassable.' (John Tyndall, 'Mathematics and Physics', 1868).

PS: Cf. Herr Kant (himself too much a modernsky): 'A well-grounded critical objection can be made against the common doctrinal opinion of physical influence. The sort of community that is claimed to occur between two species of substances, thinking and extended, is grounded on a crude dualism, and makes the latter substances, which are nothing but mere representations of the thinking subject, into things subsisting for themselves ... Thus if one separates out everything imaginary, the notorious question about the community between what thinks and what is extended would merely come to this: How is outer intuition - namely, that of space (the filling of it: by shape and motion) - possible at all in a thinking subject? But it is not possible for any human being to find an answer to this question, and no one will ever fill this gap in our knowledge, but rather only indicate it, by ascribing outer appearances to a transcendental object that is the cause of this species of representations, with which cause, however, we have no acquaintance at all, nor will we ever get a concept of it.' (Critique of Pure Reason, pp. 437-438 in the Cambridge ed.)

THE Philosopher ...

Descartes

In the later mediæval period, Aristotle was the philosopher.* His four-cause, act-potency metaphysic was that on which all major thinkers of the time erected their systems. For hundreds of years philosophers were Aristotelian as a matter of course. Their disagreements were intra-Aristotelian disagreements (which is not to trivialise them). And as contrary as, say, Aquinas and Occam were, they were both students of their master, Aristoteles. But from the early modern period onward, Descartes has mastered philosophy. He is for us the philosopher, not Aristotle. (And we're so Cartesian that, save by special training, we can't even read Aristotle without reading Descartes into him.) Descartes has set the terms of the debate, from mid-seventeenth century to present day. His qualia-quanta duoverse is that in which philosophers and scientists move. Our disagreements are intra-Cartesian disagreements. But whereas Peripateticism was explicit in mediæval philosophy, Cartesianism nowadays is almost always implicit. Today's neuroscientists, for example, are by and large Cartesian. Their logico-conceptual grammar is Descartes'. Etc. Yet they're generally unaware of this. Thirteenth-century academics in debate would quote Aristotle back and forth (as their auctor), but if neuroscientists speak the name of Descartes aloud, they don't do so with deference, for he's a superseded historical curiosity to them. Still, a crypto-Cartesian metaphysic is no less Cartesian for the prefix. E.A. Burtt is apposite here:

'The only way to avoid becoming a metaphysician is to say nothing ... Even the attempt to escape metaphysics is no sooner put in the form of a proposition than it is seen to involve highly significant metaphysical postulates ... What kind of metaphysics are you likely to cherish when you sturdily suppose yourself to be free from the abomination? Of course it goes without saying that in this case your metaphysics will be held uncritically because it is unconscious; moreover, it will be passed on to others far more readily than your other notions inasmuch as it will be propagated by insinuation rather than by direct argument. Now the history of mind reveals pretty clearly that the thinker who decries metaphysics will actually hold metaphysical notions ... He will share the ideas of his age on ultimate questions, so far as such ideas do not run counter to his interests or awaken his criticism. No one has yet appeared in human history, not even the most profoundly critical intellect, in whom no important idola theatri can be detected, but the metaphysician will at least be superior to his opponent in this respect, in that he will be constantly on his guard against the surreptitious entrance and unquestioned influence of such notions.' (The Metaphysical Foundations of Modern Science, pp. 227-229.)

To see just how radically dissimilar the Aristotelian and Cartesian metaphysics are, consider their philosophies of psychology. For an Aristotelian, body and soul as such are but abstractæ. They are matter (hyle) and form (morphe), withal potentia and actus, which in materio-formal composition are a single concrete substance (ousia). You are not your matter, not your material cause; and you are not your form, not your formal cause; you are informed matter, ensouled body. Peripatetics further spoke of vegetative, animal, and rational souls, which bespeak powers (dynameis). Rational, animal, and vegetable souls are so ordered that the former comprehend the latter, as a quadrangle comprehends a triangle and a straight line (Aristotle, De anima, II.3). Plants have only vegetative powers (e.g. nutrition and reproduction); brute animals have vegetative powers and sensitive powers moreover (e.g. appetition and locomotion); human animals have vegetative and sensitive powers and rational powers moreover (e.g. intellection and will). Thus, soul (psuchē) is a term for the defining powers (capacities, abilities, aptitudes) of a living thing.

For a Cartesian, body (now machine) and soul (now mind) are independent, mutually exclusive concretiones in causal interaction. The mind-machine distinction is not abstract and conceptual (as above) but concrete and actual. The mind is a res cogitans, a substance the essence of which is thinking; the machine is a res extensa, a substance the essence of which is extension. That which is bodily-mechanical (material, physical, natural) is that which is quantitative. That which is soulish-mental (immaterial, nonphysical, supernatural) is that which is qualitative. And as for you, human, you just are a mind within the qualiaverse, a mind that's contingently connected to a dysteleological machine within the quantaverse. There are neither vegetative souls nor sensitive souls; there are only rational souls (i.e. minds), the modes of which (e.g. percepts) are 'thoughts' in Descartes' idiolect (Principles of Philosophy, I.9). Thus, for Descartes, the proper and primary subject of experience is the mind (whereas for Aristotle it is the animate being in toto); it is the mind to which psychological concepts literally apply. And hereby experience is solipsistically privatized, inasmuch as other minds are not directly accessible.

Sherrington

The locus of mind-machine interaction for Descartes was the pineal gland situated between the hemispheres of the brain. For Thomas Willis (a few years later) the locus was the cortex, specifically the corpus callosum. And in this way the intra-Cartesian debate continued, mutatis mutandis, into the twentieth century. Previously we talked about Alan Turing and his Cartesius-dimidius premises. In Turing's time, the most formidable name in (what we now call) neuroscience was C.S. Sherrington (1857-1952), and Sherrington kept his Cartesianism intact.

'In all those types of organism in which the physical and the psychical coexist, each of the two achieves its aims only by reason of a contact utile between them. And this liaison can rank as the final and supreme integration completing its individual. But the problem of how the liaison is effected remains unsolved ... [Scientists] place the soul in the body and attach it to the body without trying in addition to determine the reason why, or the condition of the body under which such attachment is produced. This, however, seems to be the real question.' (The Integrative Action of the Nervous System, p. xxiii).

In other words, given the supposition that soul-body interaction happens, the real question is not so much where it happens but how, and no answers are ever forthcoming.† Sherrington himself conceded defeat: 'I would submit that we have to accept the correlation, and to view it as interaction ... The theoretically impossible happens' (Man on his Nature, p. 248). Note that for an Aristotelian (like Aquinas or Scotus) there is no soul-body interaction problem, no impossibility to overcome, for there is no soul-body interaction at all. Soul and body are both abstracted from a single unified substantia, and abstractions qua abstractions do not causally interact with each other. That would be a form of nonsense. But never mind. Onwards.

Eccles

John Eccles (1903-97), who studied under and later worked with Sherrington, kept his Cartesianism intact also. In what he called the 'dualist-interactionist hypothesis,' Eccles argued that the loci of interaction were in the pyramidal cells of the motor cortex (Human Mystery, p. 217). For Eccles' research had suggested to him that 'only a specialized zone of the cerebral hemispheres is in liaison with the self-conscious mind. The term liaison brain denotes all those areas of the cerebral cortex that potentially are capable of being in direct liaison with the self-conscious mind' (ibid., p. 358). Thus Eccles, too, presupposed that, did his utmost to answer where, and was silent as to how.

Penfield

Wilder Penfield (1891-1976), also a Sherrington protege, tried to be at least a methodological Cartesius dimidius, but it wouldn't last. 

'After years of striving to explain the mind on the basis of brain-action alone, I have come to the conclusion that it is simpler (and far easier to be logical) if one adopts the hypothesis that our being does consist of two fundamental elements ... It seems to me certain that it will always be quite impossible to explain the mind on the basis of neuronal action within the brain ... I am forced to choose the proposition that our being is to be explained on the basis of two fundamental elements' (The Mystery of the Mind: A Critical Study of Consciousness and the Human Brain, p. 80).

Aristotle could reasonably interject, 'What about my proposition?' But, excuse us, Descartes is our philosopher. And one may have any metaphysic one likes, so long as it's either whole-Cartesianism or half-Cartesianism retaining the dialectic of whole-Cartesianism. (Who could ask for anything more?) The latter super-folly is today's received wisdom. Penfield had rightly argued that a whole-Descartes is 'not so improbable' as a half-Descartes, for it would be absurd to say 'that the highest brain mechanism should itself understand, and reason, and direct voluntary action' (ibid., p. 82). Yet that was back in ye olden dayes of 1975. We have stronger stomachs for absurdity in 2017. But before moving ahead to contemporary neuroscientists, note that Sherrington, Eccles, and Penfield all followed Descartes in understanding mind and body to be independent substances that causally interact, and in understanding the mind to be the proper and primary subject of experience, to be that to which psychological concepts literally apply.

To be continued.

Footsies:

*‘There is a tenacious legend that the West learnt its Aristotle from the Arabic, but the fact is that the West turned to Arabic-Latin translations only in default of the more intelligible Greek-Latin ones.’ (Bernard G. Dod, ‘Aristoteles latinus’, in The Cambridge History of Later Mediæval Philosophy, p. 52.)

†And then there is the question of when—i.e. the very o'clock, to the minute-hand if not to the second-hand, at which the soul and the body are conjoined. Behold sixteenth-century medico Jean Fernel (whom Sherrington was enamoured of): 'Made at the beginning by the supreme creator of things, [the soul] migrates in a moment of time into the prepared and equipped body of the infant; this is held to happen in the fourth month, when heart and brain are already brought to completion' (Physiologia, VII.13). That this clock-watching question is a question at all is of course a choice reductio.

Cartesius dimidius ...

Turing

'I don't want to give a definition of thinking, but if I had to I should probably be unable to say anything more about it than that it was a sort of buzzing that went on inside my head.'
—Alan Turing (BBC Third Programme, 14 January, 1952)

As a mathematician, Turing's achievements were of no small consequence. But he's also remembered for his hobbyist philosophising, for his speculative essays and public radio talks on the subject of thinking machines. Whence the more or less synonymous terms 'Turing test' and 'imitation game,' referring to the peculiar means by which he answered the question 'Can machines think?' As Turing rightly says, an answer 'should begin with definitions of the meanings of the terms "machine" and "think." ' ('Computing Machinery and Intelligence,' in Mind, 1950, p. 433). Well-defined terms (i.e. terms which are unequivocal, non-circular, extensionally-sufficient, etc.) are a necessary condition of sound arguments, alongside true premises and valid reasoning. But instead of defining his terms, Turing asks a new stand-in question:

'The new form of the problem can be described in terms of a game which we call the "imitation game." It is played with three people, a man (A), a woman (B), and an interrogator (C) who may be of either sex. The interrogator stays in a room apart from the other two. The object of the game for the interrogator is to determine which of the other two is the man and which is the woman. He knows them by labels X and Y, and at the end of the game he says either "X is A and Y is B" or "X is B and Y is A" ... We now ask the question, "What will happen when a machine takes the part of A in this game?" Will the interrogator decide wrongly as often when the game is played like this as he does when the game is played between a man and a woman? These questions replace our original, "Can machines think?" (Ibid., pp. 433-434.)

Forget 'Can machines think?' It's 'too meaningless to deserve discussion' (ibid., p. 442). The new and 'more accurate version' (ibid.) of the question is: is it theoretically possible that machines play imitation games? An affirmative answer here is ipso facto an affirmative answer there (meaninglessness notwithstanding).

The logic wants an editor. But let's back up before moving ahead. Remember, Turing was a Cartesius dimidius, a Descartes halved. For Descartes, all matter is mechanical and all organisms are machines (as substantiae extensas), THE MACHINIST (God) super-adds minds (substantiae cogitantes) to some machines, and these divinely arranged marriages are called human beings. Turing accepted that all organisms are machines full-stop, rejecting mindish super-additions thereto. So why, then, ask the thinking-machine question at all? We're machines, and we think; the nervous system is a 'continuous machine' (ibid., p. 451); and so on. OK, then. We'll make the imitation game more exclusive. We'll 'exclude from the machines men born in the usual manner' (ibid., p. 435) and we'll 'only permit digital computers to take part' (ibid., p. 436). No, that's not the point. That thinking is mechanical is built into the bottommost premises. And thus the real work has already been done. Game-like tests à la Turing are unnecessary. If thinking is (and if believing and trusting and loving and grieving are) a micro-mechanical buzzing then it's only a matter of time—'at least 100 years' Turing surmised in 1952 (BBC)—before digital computers likewise buzz.

'If now some particular machine can be described as a brain we have only to programme our digital computer to imitate it and it will also be a brain. If it is accepted that real brains, as found in animals, and in particular in men, are a sort of machine, it will follow that our digital computer suitable programmed, will behave like a brain.' (BBC Third Programme, 15 May, 1951.)

In other words: if Cartesius-dimidius premises then Cartesius-dimidius conclusions. We have been here before, too, centuries ago. For is the seventeenth-century bête-machine not already an imitation gamer? Is it not 'what an engineer would call a "proof of concept," a proof designed to show that an automaton could be made to perform all the required actions in the appropriate circumstances'? (Dennis Des Chene, Spirits and Clocks: Machine and Organism in Descartes, p. 17; cf. p. 98 ff. and p. 107 ff. And note that forcing the issue to the advantage of mechanicism necessitates a Cartesius-totum position).

Suppose computers do well at imitation gaming. But further suppose that Cartesianism is not taken for granted. What follows logically? Not much. Concluding that, therefore, these computers are thinkers would be a non sequitur. For logical validation we'd have to conflate thinking and 'thinking' (i.e. a mechanical analogue thereof)—which would be a textbook example of petitio principii—and why would we do that? If we already believe (as Turing did) that thinking is a micro-mechanical process or state inside a machine then Turing tests are superfluous exhibitions. But if we don't believe that thinking is thus then Turing tests are impotent.

In his refutatio Turing presents several possible objections to his thesis. The first is what he calls the theological objection: 'Thinking is a function of man's immortal soul. God has given an immortal soul to every man and woman, but not to any other animal or to machines. Hence no animal or machine can think.' For some reason, Turing believes this to be the traditional religious position, though he includes a footnoted disclaimer ('Computing Machinery,' p, 443): 'Possibly this view is heretical. St. Thomas Aquinas (Summa Theologiae, quoted by Bertrand Russell, p. 480) states that God cannot make a man to have no soul. But this may not be a real restriction on His powers, but only, a result of the fact that men's souls are immortal, and therefore indestructible.' The last sentence bespeaks theological ignorance, but that's to be expected of readers who learn their Summa in Russellian summaria. (For a Thomist, God can't make a man to have no soul because a formless form-matter composite is contradictory nonsense. It would be like God making a sphere that had no sphericity.) Needless to say, what Turing puts forward as orthodox is heterodox. And a better name here would be the Cartesian-dualist objection—a most persuasive objection, if you're a Cartesian dualist, but neither you nor I are.

Turing's nemesis

The only objection that Turing thinks is strong is that of paranormal activity: precognition, cryptaesthesia, telepathy, etc. 'These disturbing phenomena seem to deny all our usual scientific ideas. How we should like to discredit them! Unfortunately the statistical evidence, at least for telepathy, is overwhelming' (ibid., p. 453). In this way Descartes' banished res cogitans makes an uncanny return. And all Turing can say is: 'If telepathy is admitted it will be necessary to tighten our test up' (ibid., p. 454). Such tightening! But what if we don't want to be Cartesians at all, neither fully nor by halves? Why would we? Turing himself says: 'I have no very convincing arguments of a positive nature to support my views' (ibid.). Thanks Alan.