EVER since the great French mathematician and philosopher Rene Descartes divided the world into the material brain and immaterial mind philosophers have grappled with the so-called mind/body problem.
As Gilbert Ryle put it in his ground-breaking book The Concept of Mind: “As a man of scientific genius he (Descartes) could not but endorse the claims of mechanics, yet as a religious and moral man he could not accept, as Hobbes accepted, the discouraging rider to these claims, namely that human nature differs only in degree of complexity from clockwork. The mental could not be just a variety of the mechanical.” Disparagingly, Ryle describes this immaterial Self as the ‘ghost in the machine’ and indeed it is difficult not to think of the mind/body problem without conjuring up a sort of spiritual homunculus directing affairs from within.
Since, then, however, neurophilosophy and science have come a long way but the homunculus still makes an appearance. In Philosophy, Neuroscience and Consciousness philosopher Rex Welshon refers to what he calls the ‘central executive function’ which bleeds into the notion of a ‘metacognitive process’. And then our old friend the homunculus makes his appearance. “One particularly forceful way of putting these problems is to note that the central executive’s various functions threaten to compose a homunculus, a little person inside the brain that replicates the activity of a big person with that brain.” But as Welshon points out, this merely shifts attention from a big thing to a small thing.
However, modern neuroscientists are moving towards the idea that there is an executive function within the brain that is metacognitive and operating above the basic object-level information operations. This enables it to monitor other processes without resorting to a homunculus. “What we monitor is other thoughts, beliefs, fears and hopes, and what we do when we monitor them is adopt a distant cognitive attitude towards them, analysing their causes and consequences, for example, and assessing their fit within our overall psychological economy,” writes Welshon. If this is true it seems to counter bother the need for a ‘ghost in the machine’ and the fear that we are inherently irrational and bound to act according to external causes, because it would appear that we actually do have the ability to detect, analyse and act upon causes, even if we are not always very good at detecting, analysing and acting upon said causes.
Welshon is writing from a default naturalist position in which there still remain divisions between reductive physicalists and non-reductive physicalists. For the former ‘conscious properties are reducible to some level of physical, usually neural, property’. Most non-reductive physicalists argue that ‘conscious properties bear some other relation to physical properties that is weaker than identity but still substantial enough to warrant neuroscientific investigation’. Other non-reductionists, however, believe that some conscious properties do not ‘bear any relation substantial enough to warrant neuroscientific investigation’. It is interesting to note that the latter group is not saying that there may be a relation but we will never be able to determine what it is, but, rather, that there is no relation to investigate. And that raises the question as to what is left over. In what sphere do these conscious properties exist if they don’t have any relation to physical properties and is this position vulnerable to the re-emergence of the spiritual homunculus? Or the ‘ghost in the machine’? At one extreme we have Ryle who argues that even asking questions about reduction is a category error because the mind and body should never have been divided in the first place. At the other are thinkers like Raymond Tallis who in the latest edition of Philosophy Now argues that: “Neural activity, which does not contain generality and possibility, could not support or instantiate any general thought, least of all about thought.” This claim is based on the assertion that no event in the physical world can either have generality or possibility. Tallis clearly fits into the second class of non-reductive physicalists and seems to want to shut down any further scientific enquiry into these problem. Indeed his latest book is called Reclaiming Humanity from God and Science. But as Welshon says, although there may well come a time when neuroscience has to hang up its brain cells and admit defeat – we haven’t reached that point yet. Although one might also ask the question – how do we know?