P. M. S. Hacker - Philosophical Foundations of Neuroscience

Sherrington’s dualism

Sherrington studied Fernel carefully, and read extensively in the works of philosophers, from Aristotle onwards. But, as we shall see, his grasp of philosophical problems and his understanding of the differences between scientific problems and philosophical ones were infirm. Despite acquaintance with Aristotle’s De Anima , he failed to see the depth and fruitfulness of the Aristotelian conception of the psuche¯ and its bearing on the essentially conceptual questions that plagued him. He noted Aristotle’s ‘complete assurance that the body and its thinking are just one existence’, and that ‘the “oneness” of the living body and its mind together seems to underlie the whole [Aristotelian] description as a datum for it all’. 2Nevertheless, Sherrington did not probe the Aristotelian philosophical doctrine properly. Instead, he moved towards a dualist conception of the relation between mind and body, unsurprisingly encountering the same insoluble problems as Descartes had in the seventeenth century. Using the term ‘energy’ to signify matter as well as energy, Sherrington held that ‘evolution has dealt with … us as compounded of “energy” and “psyche”, and has treated in us each of those two components along with the other. The two components are respectively, on our analysis, an energy-system and a mental system conjoined into one bivalent individual’ ( MN 250). ‘Energy’, or matter, and mind are, he thought, ‘phenomena of two categories’ ( MN 251).

Sherrington’s conception of mind

‘Energy’, in his view, is perceptible, spatio-temporally locatable, subject to the laws of physics and chemistry. Mind, by contrast, is ‘invisible’, ‘intangible’, without ‘sensual [sensory] confirmation’ ( MN 256). Sometimes Sherrington states that mind is ‘unextended’; 3at others he states that since mind has a location, it is inconceivable to him that it should lack a magnitude or be without extension. ‘Accepting finite mind as having a “where” and that “where” within the brain, we find that the energy-system with which we correlate the mind has of course extension and parts … Different “wheres” in the brain correlate with different mental actions … We have to accept that finite mind is in extended space’ ( MN 249f.). On the other hand, he remarks, more sapiently than he evidently realized, that the mind is not ‘a thing’ ( MN 256). He conceived of mind as the agent of thought, the source of desire, zest, truth, love, knowledge, values – of all, as he put it, ‘that counts in life’ ( MN 256). It is, he wrote, ‘the conscious “I”’. 4But this is misconceived. The mind is no more located in the head or brain than is the ability to walk or talk. It is neither extended, nor an unextended point, any more than the ability to score a goal is either extended or an unextended point. The mind is not ‘the conscious “I”’, since there is no such thing as ‘an I’, any more than there is such a thing as ‘a you’ or ‘a he’ (see below, §14.4). I am not my mind – I have a mind, not as I have a car, or even as I have a head or a brain, but rather as I have eyesight or the ability to think.

Sherrington’s conception of the relation between mind and body

How we should conceive of the conceptual relationships between mind, body (and brain) and person is a deep philosophical problem – the character of whose solution we have intimated, and shall discuss below (see, e.g., §4.8). Sherrington was exceedingly unclear about the issue, not fully realizing that this is not an empirical problem at all, but a purely conceptual one. Sometimes he seems to accept the mistaken idea that the mind has a body, 5even though, to be sure, it is not minds that ‘have bodies’, it is human beings . 6At other times he seems to go so far as to claim that the body (or at any rate parts of the body) has (or have) a mind – a part of the body that is sensitive has ‘mind only lent it, in the form of sensation by proxy’ ( MN 187). But this is confused. What would a body do with a mind? People , human beings , have minds as, indeed, they have bodies. ‘So much of the body as feels, has its sensations done for it’ by the brain, Sherrington argued, and so too, ‘the body’s thinking seems to be done for it, namely in the brain’ ( MN 187), presumably by the mind. Here too he was confused, since the brain does not ‘do’ sensations – there is no such thing as ‘doing’ sensations. But we have sensations in various parts of our sensitive body (parts that hurt, throb, itch, etc.) – and we would have no sensations but for the normal functioning of the brain and the nervous system (see §5.1). Similarly, the body has no thinking to do – there is no such thing as one’s body thinking. It is human beings who think, and their thinking is not done for them by their brain – they have to do their own thinking (see §7.2). There is no such thing as the brain’s thinking anything – although, of course, human beings would not be able to think but for the normal functioning of their brain. ( That, to be sure, does not imply that one thinks with one’s brain, in the sense in which one walks with one’s legs or sees with one’s eyes.)

Sherrington on the mind–brain nexus: misunderstandings of Aristotle

Given this confused dualism, the question of the relation between the two putative entities cannot but arise. Sherrington asserted that no one doubts that there is, as he put it, ‘a liaison’ between brain and mind. But ‘The “how” of it we must think remains for science as for philosophy a riddle pressing to be read’ ( MN 190).

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; it remains where Aristotle left it more than two thousand years ago. There is, however, one peculiar inconsistency which we may note as marking this and many other psychological theories. They 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, would seem to be a real question. 7

It is curious to find Sherrington writing this, since he knew that the question of how the mind can interact with the body is not a question that can arise for Aristotle. Within the framework of Aristotelian thought, as we have seen (§1.1), the very question is as senseless as the question ‘How can the shape of the table interact with the wood of the table?’ Aristotle manifestly did not leave this as a problem within his philosophy. The problem arose within the framework of Plato’s dualist philosophy, which was contested by Aristotle but nevertheless informed Neoplatonism and, via Saint Augustine, came to dominate Christian thought. To be sure, Thomas Aquinas adopted Aristotelian psychology and strove, with questionable coherence, to adapt it to Christian theology. But Platonic dualism remained the most natural conception for popular Christianity, and it informed the Renaissance form of Neoplatonism. The relationship between mind and body is highly problematic for any form of dualism, and with the seventeenth-century dominance of Descartes and the corresponding decline in the influence of Aristotelian philosophy, the problem of interaction came on to the agenda again, and has remained there ever since.

Sherrington on the irreducibility of the mental