To: Daniel R.
From: Geoffrey Klempner
Subject: Descartes and the problem of mind-body interaction
Date: 24 August 2005 11:57

Dear Dan,

Thank you for your email of 16 August, with your University of London BA essay in response to the question, 'Is Descartes right to assert that there is a real distinction between mind and body? Does the distinction leave Descartes with insoluble problems about their interaction?'

In response to the first part of the question, you give a careful analysis of the arguments Descartes deploys in asserting the real distinction between mind and body, pointing out the non-sequiturs. You also offer a more general diagnosis of what has gone wrong ('moving from a subjective epistemological claim to an objective ontology', 'move from imagining this situation to proving that it is necessarily the case').

I think an examiner would be justified in feeling that you had not directly answered the question, 'Is Descartes right to assert that three is a real distinction...?', but instead answered a different question, 'Does Descartes argue validly for a real distinction...?' There are dualists who would argue that Descartes' arguments are invalid as they are stated in the Meditations, but they can be patched up, fixed to appear much more formidable.

When looking at any historical philosopher, this is always an option to take into consideration. Some times, though not always, it is legitimate to claim that the extra premisses were 'implicit' in the text.

(Reading this through a second time, it has occurred to me that there is an ambiguity in the question - which you would be perfectly justified in pointing out. On one reading, if dualism is true, then whatever you think of Descartes arguments in the Meditations he is right to assert what he asserts. On the other reading, if Descartes argued invalidly, then he was not right in asserting what he asserted, even if what he said was true. The fact that it is raining doesn't make it right for me to assert that it is raining even if what I said is 'right', if there was no way I could have known that it was raining.)

At the end of the day, the 'beefed-up' arguments for dualism can be defeated - as some would claim, by using Wittgenstein's destructive critique of the notion of a 'private language'. But that's hard work. Reading your essay, it is difficult to get a sense of the powerful attraction of the dualist vision.

In other words, I guess what I missed here was some recognition of the 'grippingness' of Descartes vision. He is not just some historical philosopher who committed a curious fallacy which other thinkers have unfortunately replicated.

Kripke's argument is directed against materialist philosophers like Armstrong and Smart who in your terms exploit the 'ignorance' gap between subjective certainty and objective ontology. It does not follow from the possibility of imagining my mind existing in a non-material reality alone with the evil demon, that my mind is not, as a matter of brute contingent fact, identical with matter.

However, as Arnaud's objection shows, there is another possible strategy for defending materialism which does not depend on the claim of contingent identity, namely, to demonstrate - just as Pythagoras demonstrated the properties of the right angled triangle - that the very notion of experience necessarily involves the existence of a material world: in other words, what Descartes claims to imagine is not really conceivable after all.

Regarding interaction, neither the point about the pilot and the ship, nor the careful analysis of how false beliefs arise really address the difficulty.

Descartes claims that interaction - if it occurs - is fully consistent with the subjective experience of being an agent in a physical world. And I think on this he is right. The point about false belief is relevant to the question which is very worrying for Descartes but less so for us, of how a non-deceiving God can permit any false beliefs to arise.

However, a relevant consideration which you might have considered, which arises in relation to Leibniz's criticisms of Descartes, is that in Cartesian physics mind-body interaction does not violate conservation principles. Cartesian physics is based on the a priori analysis of extension alone. No energy is required, Descartes thought, simply to 'divert' the animal spirits in a different direction.

For Descartes, the only problem is the non-location of mind: lacking physical attributes, mind cannot occupy space or be at one place rather than another. However, as the exchange with Elizabeth seems to indicate, he would reply that the phenomena of magnetism or gravity show that physical contact is not required for causal interaction.

All the best,

Geoffrey