To: Aalia S.
From: Geoffrey Klempner
Subject: Descartes: 'I am a thing that thinks'
Date: 10th June 2008 13:07

Dear Aalia,

Thank you for your email of 1 June, with your University of London essay in response to the question, ''I am a thing that thinks.' Explain and evaluate the reasoning which leads Descartes in this conclusion.'

I would describe what you have given in this essay is a good 'precis' of Descartes' argument. In case you are not familiar with the term, 'precis' is a word originally from French which, in English, refers to a condensed version of a piece of writing which preserves the substance of what the writer said.

The important rule for writing a precis is that you don't add anything or take anything away. Everything essential to what the author intended is there, with no unnecessary additions. This is different from giving an explanation, which is what the exam question wants you to do.

The best way to grasp the difference between a precis and an explanation is to imagine that you have a friend who is rather sceptical, who is interested in knowing what the author (e.g. Descartes) said. You start by attempting to give a precis, but your friend interrupts you with a barrage of objections:

'What is the definition of a 'thing'?

How can there be such a thing as a 'thing' which has no size or shape or position?

How is pain, or the sensation of red an example of 'thinking'?

How do I know that when I say 'I exist' at 5 pm and then say 'I exist' at 6 pm, the term 'I' refers to the same thing on the two different occasions rather than two different things?

-- Your argumentative friend is forcing you to explain and evaluate Descartes' argument rather than just repeating it.

It is, in fact, very difficult in philosophy to distinguish the 'explanation' of an argument from evaluation. In explaining an argument, you are trying to show how the argument is meant to work, why it is convincing or at least appears to be convincing. This forces you to consider questions of evaluation -- how good the argument it is, whether the premisses are true, the reasoning sound and so on.

Let's cut to the chase:

You have not written a bad essay, given the limited objectives that you have set yourself. However, the examiner is looking for more. At the very least, the examiner wants to know whether you AGREE with Descartes' reasoning or whether you see some flaws.

To your credit, you do mention the 'anti-Cartesian', however the only argument you put into the mouth of the anti-Cartesian is, 'if a person dies, he stops thinking'. This is not a convincing argument from Descartes' point of view because we just don't know what happens when a person dies. Obviously, we don't see any thinking taking place, but that doesn't prove that no thinking is occurring. If a person is a soul attached to a body, and it is the soul that does the thinking, then of course when the body dies only the soul knows that it is thinking and no-one else can know this.

What would be a convincing argument against the Cartesian is one which follows up on some of the questions I raised earlier (as your 'argumentative friend').

Consider the question of the identity of the soul. The philosopher Kant, in his 'Critique of Pure Reason' (in the section grandly entitled, 'Paralogisms of Transcendental Psychology') put forward a devastating objection, which uses Descartes own method of doubt as the starting point: I cannot doubt that I exist, at this very moment. However, suppose my soul substance dies, and is replaced by an identical 'soul substance' with exactly the same memories, the same sense of being ME, then I would never know.

Bertrand Russell once remarked that if the world had been created five minutes ago, and the human race along with it each person with a full set of 'apparent' memories, then we would never know the difference. Memories refer to the past, but the memory experience is something which exists only in the present. So you can have a 'memory experience' even if the memory is, in fact, false.

Kant suggests an amusing picture of this: imagine that the thing you call 'I' is not a single substance but more like a line of colliding balls each one of which passes its motion to the next ball in the line. In other words the 'I' is not a thing but rather a series of momentary 'I-events'.

The conclusion is that, on the basis of the method of systematic doubt, I cannot call myself a 'thinking thing' but only a 'thinking event', which is pretty devastating for Descartes' soul hypothesis.

Strawson, in his piece 'Self, Mind and Body' takes Kant's objection and develops it further. I won't say any more about Strawson's piece, because you need to read it for yourself. The examiner would expect you to be familiar with Strawson's arguments, which are in fact highly relevant to the question you have answered.

All the best,

Geoffrey