The Mind/Body Problem

Jonathan Westphal is an Oxford philosopher who has written a book on the mind/body problem in philosophy, and the MIT website The Reader has an interesting article by Westphal that's excerpted from his book.

The mind/body or mind/brain problem is essentially the problem of ascertaining whether we are simply a material, physical being, a body, or whether, in addition to our material selves we also have an immaterial mind that's non-physical and non-spatial.

The article begins by giving a description of the problem based on an everyday event such as seeing a cup of coffee:

[T]he physical story is that light enters my eyes from the cup of coffee, and this light impinges on the two retinas at the backs of the eyes. Then, as we have learned from physiological science, the two retinas send electrical signals past the optic chiasm down the optic nerve.

These signals are conveyed to the so-called visual cortex at the back of the brain. And then there is a sort of a miracle.

The visual cortex becomes active, and I see the coffee cup. I am conscious of the cup, we might even say, though it is not clear what this means and how it differs from saying that I see the cup.

It does indeed seem miraculous. No one knows how it happens that chemical reactions in the brain produce an image that seems to be in the brain but which is invisible to any outside observer examining the brain. Only the individual looking at the cup "sees" the image. No one looking at his brain can see what he's seeing. Westphal goes on:

One minute there are just neurons firing away, and no image of the cup of coffee. The next, there it is; I see the cup of coffee, a foot away. How did my neurons contact me or my mind or consciousness, and stamp there the image of the cup of coffee for me?

It’s a mystery. That mystery is the mind-body problem.

Part of the mystery consists in explaining what exactly the image of the coffee cup is and how electrochemical impulses flowing along a neuron could produce it. After all, brain matter is physical matter, it's spatial, but the image is immaterial and non-spatial. We say it's in our brains but if we could peer inside our brains we wouldn't see a picture of a coffee cup anywhere. So how does matter produce an immaterial image?

A number of philosophers have argued that it's inconceivable that two fundamentally disparate substances, such as matter and mind must be, can interact and that therefore we should only posit a single substance responsible for our "mental" phenomena, the physical brain. This view is called materialism.

Westphal quotes the 17th century French philosopher Descartes:

The whole problem contained in such questions arises simply from a supposition that is false and cannot in any way be proved, namely that, if the soul [mind] and the body are two substances whose nature is different, this prevents them from being able to act on each other.

Descartes seems correct about this. If I hit my thumb with a hammer, everything that happens subsequently is physical and material, except the pain. Pain is non-spatial. It's an immaterial sensation, so where does it come from? Indeed, what exactly, is it?

Westphal describes the problem using not pain but color:

We see that the experiences we have, such as experiences of color, are indeed very different from the electromagnetic radiation that ultimately produces them, or from the activity of the neurons in the brain. We are bound to wonder how the uncolored radiation can produce the color, even if its effects can be followed as far as the neurons in the visual cortex.

So how do physical causes produce non-physical effects? Westphal again:

What happens,...for example, when we decide to do even such a simple thing as to lift up a cup and take a sip of coffee? The arm moves, but it is difficult to see how the thought or desire could make that happen. It is as though a ghost were to try to lift up a coffee cup.

Yet, the fact that our immaterial thought, the thought of raising our arm, triggers a cascade of physical effects is astonishing. No one knows how it happens, but that it happens is one of the chief reasons many philosophers today have rejected materialism and embrace the belief that there's more to us than just our physical bodies.

We must, these philosophers are convinced, also possess a non-physical, immaterial mind or soul.

There's more from Westphal at the link, but you might wonder what's at stake in the controversy between those who believe that we're just material beings (materialists) and those who believe we're a composite of matter and mind (dualists).

That'll be the topic of tomorrow's post.