1. The Mind-Body Problem The mind-body problem has remained essentially unchanged since Descartes put it forward in 1641. The problem is: what is the nature of the conscious mind, and how does it relate to the body? Today, the prevailing view is that the mind is really a physical phenomenon going on inside the brain. I shall call this view physicalism. It contrasts with two other broad views: dualism which says the mind is irreducibly different from the brain; and mentalism which denies the existence of the brain altogether.
I shall describe a hypothetical experiment that could in principle be carried out on a conscious brain. Then I shall consider what result the doctrine of physicalism predicts as the outcome of this experiment. I shall suggest that that outcome is rather implausible and that it throws doubt on physicalism.
The experiment illustrates a basic problem, which Descartes elucidated in his Meditations.
It is that the brain is extended in space and can therefore be dissected into parts, whereas the mind is not extended in space. The mind thus has a unity that the brain lacks.
2. Where is my mind? In everyday life, I imagine each element of my mind as residing in the relevant part of my body. Tactile sensations are a good example of what I mean by this: if I were to drop this word-processor on my foot, then I would obviously have a sharp pain in my foot. Other people seem to have roughly the same intuitive idea of where they are in their bodies. Admittedly, there are some differences. For instance, people variously locate their emotions in the chest, the belly, or the head.
In general, therefore, our intuitive idea of the mind's location is that it is interfused with the whole body. But where...