To: Aalia S.
From: Geoffrey Klempner
Subject: How Descartes puts the case for doubt in 1st Meditation
Date: 19th May 2008 11:03

Dear Aalia,

Thank you for your email of 10 April, with your University of London Introduction to Philosophy essay, in response to the question, 'In his First Meditation, how does Descartes attempt to show that there is reason to doubt everything one believes?'

You have given a reasonably good summary of the stages of Descartes' argument in the First Meditation, although with one or two gaps which I will explain in a minute.

At the end of the essay, you also offer information which is strictly not required in order to answer the question: the scientific context in which Descartes developed his method -- the experimental work of Galileo which demonstrated that Aristotle's authority was not beyond question -- and also the next stage of the argument, the discovery of the cogito.

Examiners will routinely ignore anything which is not relevant to the question being asked. You can even lose marks. So I would say that the essay would be better without these additions. Concentrate on answering the question, and giving the best arguments that you can in support of your conclusions.

This is a difficult question to tackle because, on the surface, it simply asks for a report on what Descartes says, which is what you give. You do express reservations at one stage -- where Descartes argues that he ought to be more prone to error if the being who created him is less than a perfect deity -- although you comment that you 'do not find his arguments on this point clear enough' doesn't elaborate further.

What the examiner is looking for is critique, and not just description. The examiner wants you to look at the arguments that Descartes offers in support of the proposition that there is 'reason to doubt everything one believes' and assess whether, in your view, those arguments are sound. If you agree with Descartes, you can still put forward objections that someone might have to his argument, and then show how you think Descartes would respond to those objections.

If it is not clear exactly what Descartes is arguing for, then this too is a suitable subject matter for discussion. If there are different possible interpretations of a particular stage in the argument, then you have to give the reasons for preferring one interpretation to another.

Descartes begins with the observation that we are sometimes deceived by our senses, and you offer some helpful examples of this. Actually, your examples raise greater doubts than those that Descartes considers (such as 'round tower looks square from a distance') because the implication is that we cannot even be certain about the contents of our own consciousness -- the very thing that Descartes, in the next Meditation, argues is beyond question!

For example, consider your example of anger. Your friends think you are angry with them, from observing your behaviour, but their judgement is incorrect. You are just excited. However, can't you be wrong about your own feelings? Can't you be angry and not realize that you are, or not angry and think you are angry? Psychotherapists routinely tell their patients that they are making incorrect judgements about what they think they feel, that they are 'deceiving themselves' about their true feelings.

However, to get back to the First Meditation, you do miss an important objection that Descartes considers with regard to perception: that errors of perception (such as the one about the round tower) are corrected by further perceptual judgements. For example, you go closer to the round tower and see that your original judgement was incorrect. That is why Descartes has to consider the more radical doubt regarding being asleep or being awake.

Another point that you overlook is when Descartes raises the possibility that he is a madman, only to immediately dismiss it. Is he right to do this? If he is considering every possibility, including the possibility that he might be dreaming, shouldn't he also seriously consider the possibility that he is mad? If not, why not? What do you think?

The point that you had difficulty with could be explained in this way. Descartes says that God could, if he wished, make him such that he is deceived about even simple arithmetical additions. Now suppose that Descartes was not created by God but by super-intelligent mice (as in Douglas Adams 'The Hitchhikers Guide to the Galaxy'). Even if the mice are very clever they are still fallible. The original Intel Pentium processor had a bug which made it give the incorrect result for certain arithmetical calculations. If my brain was made by mice -- or by Intel -- then how can I be sure that my it doesn't have a similar bug?

One thing that I wasn't clear about from what you said is exactly what is thrown into doubt, by the end of the First Meditation. What does the hypothesis of an evil demon accomplish? A good point to make here is that the evil demon is not just an 'evil scientist' (who attaches wires to your brain and gives you experiences which you wrongly interpret as normal perception). If you've seen any of the Matrix films, you will be familiar with the idea that you might be asleep in a pod, 'dreaming' that you are preparing for your UoL exams.

The evil demon goes further than this. Descartes wants to show that there is reason even to doubt that there exists space, and space-occupying objects. In other words, there is nothing outside the dream, other than the evil demon, no story about lying in a pod, or on a bed or whatever.

Does that hypothesis even make sense? What kind of world would it be, if nothing exists -- no space, no objects, no universe -- apart from my consciousness and the evil demon? That's something to think about.

All the best,

Geoffrey