To: Anna H.
From: Geoffrey Klempner
Subject: Mind-body problem: interactionism vs epiphenomenalism
Date: 9th February 2011 12:02

Dear Anna,

Thank you for your email of 1 February, with your third essay for the Philosophy of Mind program, in response to the question, 'Contrast the main features of 'Interactionist' and 'Epiphenomenalist' versions of mind-body dualism.'

I can see that you have been looking at contemporary discussions of epiphenomenalism and have found them somewhat confusing, when related to what is said about epiphenomenalism in the program. We are actually dealing with two very different theories.

Much of the contemporary discussion is about 'epiphenomenalism' conceived as a view which is broadly consistent with materialism and not a version of mind-body dualism. The idea relates to the notion of 'folk psychology' as giving a more or less inaccurate picture of what is 'really going on' in the brain. We need this picture, we use it every day, but it is just a cultural artifact nothing more, something that enables us to function as 'persons' who engage other individuals in dialogue and treat them as 'persons' like us rather than as things.

What is 'really going on' in the mind/ brain is said to be the province of the neurophilosopher. You and I wouldn't recognize an explanation of our behaviour from the neurophilosophical point of view, although it is in some sense 'the truth' about the causes and effects which operate at the most basic level. Much of what we believe about ourselves, on the level of conscious reflection or folk psychology is just mythology, necessary for practical purposes maybe but not the truth.

This is materialism, and moreover a rather reductive version of materialism which seeks to eliminate mental phenomena rather than explain them. Our view of what is going on, through introspection or folk psychology, is just not relevant.

The version of epiphenomenalism that I discuss in the program is very different. Epiphenomenalism poses a direct challenge to materialism -- any version of materialism -- by asserting that it is logically possible that a perfect duplicate of GK could lack the extra something 'inside' that the original GK has, the variegated qualities of consciousness. The duplicate GK would talk just as I do, and therefore would say the very same things I say about 'the variegated qualities of consciousness' but that's all it would be -- talk. This is the 'zombie' thought experiment. The duplicate GK is a zombie, who is in all respects indistinguishable from me.

However, there is another way of posing the zombie question, which you mention in your essay: 'Without this 'interactionist soul', the brain is just a blind mechanism incapable of thinking for itself.' The finesse here is to point out that, at the present stage of scientific knowledge of the workings of the human brain, we just don't know for sure whether the brain in its physical embodiment is completely self-sufficient, or whether, as Descartes believed, it requires some kind of 'push' from outside to make it go.

This suggests the possibility of a different kind of 'zombie', more like the zombies in zombie movies, which walks around in a jerky way, is able to perform basic repetitive actions but nothing that requires thinking or deliberation. Maybe there is something else, something that does not belong to physics, which accounts for the way the brain works. Call it 'super-physical'. I'm not thinking of 'quantum effects', although maybe these could be somehow 'manipulated' by the super-physical aspect which escapes scientific description.

Is this just wild speculation? The point is about knowledge. We don't know for sure that the brain suffices to explain our capacity for conscious thought etc. We assume that it does. The second zombie scenario suggests that things could turn out otherwise.

But would this be dualism? Surely not in the Cartesian sense, because the whole point about Descartes' original argument for mind-body dualism is that I *know*, with complete certainty, that I would exist even if all physical things did not. The very same argument can be run for the hypothesized 'super-physical' something that makes the brain go. I *know*, with complete certainty, that I would exist even if neither physical nor super-physical things existed. The reason the argument works is that my knowledge of myself is from the 'first person' while any kind of entity or stuff, whether physical or super-physical, is conceived as having objective existence apart how things appear from my subjective point of view.

As you will gather from the program, I reject Descartes' argument. That doesn't automatically make me a materialist, for the reasons stated. I'm doubtful about the idea that there could be more to the world than the entities of physics (which already allows for layer upon layer of scientific description -- chemistry, biochemistry, biology, etc.). But neither can one be certain that everything is physical. It's just a working assumption that scientists make which could turn out to be false.

All the best,

Geoffrey