Wednesday, January 16, 2013

Case for doubt in Descartes First Meditation

To: Francis W.
From: Geoffrey Klempner
Subject: Case for doubt in Descartes First Meditation
Date: 17th February 2009 11:24

Dear Francis,

Thank you for your email of 7 February, with your essay for the University of London Diploma in Philosophy Introductory module, in response to the question, 'In his First Meditation, how does Descartes attempt to show that there is reason to doubt everything one believes?'

This is a well structured answer to the question, and you would get credit for your description of the overall strategy of Descartes' argument in terms of: 'argues something that should be doubted', 'finds a reason to eliminate the doubt', 'finds a new reason to push the doubt further', and so on.

One question you could have raised is why Descartes uses this strategy? If you have three arguments, the first which is just OK, the second which is much better, and the third which is a knockout, why not just go for the knockout? Why waste time rehearsing arguments which are less persuasive?

One obvious answer would be that Descartes' purpose is heuristic: he is not just trying to persuade you but trying to teach you; guiding you in easy stages to the final conclusion, so that you will understand that conclusion better than if you had been hit with the knockout argument straight away.

I don't think that's the whole truth however. The earlier arguments, in my view, establish conclusions which are needed for the final 'evil demon' argument. The argument from the senses is used to establish a sense of the term 'perception' which refers to a representation in our mind which either corresponds or fails to correspond with things in the world. For example, the perception of a tower in the distance which represents the tower as being square when in fact it is round.

Similarly, in the dreaming argument, Descartes establishes (or thinks he has established) that a coherent sequence of experiences is possible in the absence of anything in the world to which that sequence of experiences corresponds.

Under the heading of 'the senses argument' you say something rather strange, 'How could one [be] sure that the hands before him are the one[s] [which] belong to him [rather than] someone else?' (I've corrected your English here).

This is a very odd thought. I think you have misunderstood this passage. But let's ask the question, anyway.

Under what circumstances might I doubt that my hands are mine? For example, I try to write an email to FW in response to his essay on Descartes, and 'my' hands start typing something totally different -- a poem, or a stream of insults -- totally out of my control. I would conclude from this that another person (maybe a wicked witch) had 'taken control of my hands', so that they are no longer 'mine'. (On the principle that a limb 'belongs' to the agent who is able to move that limb.) One could imagine room for a neurotic doubt here. Suppose that as a result of my doubt I keep doing things with my hands to 'test' that they are still mine and haven't been taken over by a wicked witch. You can see the problem. However many times I succeed, the doubt remains that my hands might at any time cease to be under my control, proving that they weren't 'my' hands after all. The wicked witch was just letting me use them for a while.

This is not a scenario Descartes considers, although it is a perfectly good example of a sceptical hypothesis, leading to the alleged conclusion that no-one 'knows' that their body is theirs. (There are interesting conclusions to draw from this concerning the nature of the will, and how the will relates to the external world.)

Getting back to Descartes, it is significant that he dismisses the worry that he might be a madman -- but why? Wouldn't this be the ultimately irrefutable argument? You can't prove that you are sane, because if you were mad, you would think you were sane and find plenty of arguments to prove it. This shows that, for all his doubting, Descartes is not willing to let go of one key assumption: that he is capable of reasoning. If you give up this assumption, then any attempt at reasoned argument becomes impossible.

In your review of Descartes' arguments, you give three objections. The first objection is that he restricts 'the senses' to the sense of sight. Now, this I agree with: it is important to Descartes' strategy in the Meditations that he sees the subject as essentially an 'observer' cut off from immediate contact with the world. In other words, a powerful strategy for resisting Descartes' sceptical argument is to point out that the self is essentially an agent not a 'passive observer'.

However, you weaken your case by giving as an example meeting someone and romantically 'knowing' that they are the one for you. Descartes would say, 'How do you know that this intuitive sense is reliable?' The answer is that these judgements are 'tested' by subsequent experience (you live happily ever after with your true love). In other words, intuitive judgements like this depend for their epistemic credentials on our normal ways of accessing information about the world.

Your second objection is merely a version of one that Descartes gives to the dreaming hypothesis. It is not very strong. It is true that (as Descartes says) our dreams are made up of bits and pieces taken from our waking experience. But that doesn't help me if, for example, such strange things have begun to happen that I really begin to wonder whether I am awake or dreaming. Maybe I was awake once; maybe it was necessary to have been awake in order to have material to dream. But my (Descartes') worry is that I don't know whether or not I am dreaming *now*, and if I don't know this then I can't base any judgement on experience.

Your third objection is to the 'evil demon' hypothesis. You argue that there could not be an evil demon if there was no God. Well, that's your belief. But Descartes' isn't saying, 'I know that there is an evil demon', he is saying, 'I don't know that there is not an evil demon'. Maybe I don't know how there could be an evil demon unless God made it. I might also have the same view about the existence of the world. But that's all irrelevant because that's just another belief which I have. Descartes' argument for scepticism destroys -- or attempts to destroy -- the basis for all such beliefs.

All the best,

Geoffrey