Tung asked:
Can Cartesian dualism successfully account for the existence of consciousness?
Answer by Geoffrey Klempner
This question is deeper than it looks. The question we have to address isn’t how Cartesian dualism compares with other theories of the mind such as material monism, or even whether Cartesian dualism is a defensible theory. Then, what?
Imagine that no-one has ever thought of an alternative to dualism. The very idea of a materialist explanation of consciousness has never occurred to anyone, ever. Cartesian dualism states that there exist two fundamentally different kinds of substance in reality. These two types of substance are identified by their essential properties. The essential property of material substance is that it has mass and occupies space. The essential property of mental substance is that it is presented in consciousness to an ‘I’, a subject of thought and experience.
But why does consciousness exist? Why does material substance exist? Maybe Descartes was wrong about God being the Creator. Maybe, it would not be so bad if we just had to accept contingent existence as the beginning of everything, as in my five-word treatise on Metaphysics:
Something exists.
Deal with it.
Something exists. It’s just a fact. And what exists, according to the dualist, is two kinds of ‘something’, a material universe in space and time, and a conscious subject, or subjects like you and me.
On this view, ‘accounting’ for the existence of consciousness means exactly what it says: we are taking an account, making an inventory OF reality (as I argued in my book Naive Metaphysics). This isn’t ‘accounting-for’ in the sense of explaining (as in, for example, the deductive-nomological model of explanation proposed by Carl Hempel) but rather just acknowledging what is there. Acknowledging a fact, the fact that consciousness exists.
But this is where things begin to get fuzzy.
I said, ‘the fact that consciousness exists’. Whose consciousness? Yours, maybe? You can take it as read that I am talking about you, whomsoever you are — whoever happens to be reading this — but as far as I am concerned is very far from being a ‘fact’ that you exist at all, let alone your ‘consciousness’. I don’t know you. And even if I did, there’s that worrying epistemological gap between perception of a another person’s speech and behaviour and the supposition, or assumption — or inference? — that there ‘exists’ something ‘inside’ that accounts for these outward physical manifestations.
No, I am talking about myself. Just as Descartes did. I know that I exist. I know my consciousness, or, at least, I know it now, at this very moment in time (maybe my memory systematically deceives me, maybe I have only existed for these few seconds, maybe…).
I know that I exist now. What kind of knowledge is that? Knowing that I exist now, at this moment, I also know that this ‘existence’ is not necessary but contingent. I might not have existed now, at this moment. And what then? One possibility is that the author of this post was never born. There was no individual called ‘GK’. My parents’ only son was called Simon Klempner, and he became a successful City of London banker.
But it is the other possibility that troubles me: that GK was born, sixty-nine years ago give or take a few days, studied Philosophy, got his doctorate, ended up here, on a high and very bare plateau of his own creation, posting his lonely thoughts on the Internet. But that GK, be he ever-so much like me, is not I. Because I never existed:
I might not have existed but someone exactly like me might have existed in my place.
Obviously — duh! — Cartesian dualism cannot account for there being I, because it can’t explain why I exist rather than someone exactly like me who is not I. My existence or non-existence is not to be ‘accounted for’ on the basis of the existence or non-existence of some substance, as Descartes thought. The metaphysical theory of substance, which he derived from the great Aristotle, is simply inadequate to account for what is.
What is, is that there is a world, and there is I. Or, in the words of Ludwig Wittgenstein in his 1914-16 Notebooks:
“There are two godheads: the world and my independent I.”
Later, in his Tractatus Logico-Philosophicus, Wittgenstein pulled back from this momentous claim, realizing that according to his own theory of language and meaning, the thing he wanted to say simply could not be said, or even ‘thought’. Wittgenstein’s contemporary, the redoubtable Frank Ramsay alluding to his teacher’s fondness for playing the recorder quipped, ‘What you can’t say you can’t say, and you can’t whistle it either.’
— I will leave the question there, because I don’t know what else there is to say.
Ask a Philosopher 
