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Descartes' argument for doubt in the First Meditation


To: Scott B.
From: Geoffrey Klempner
Subject: Descartes' argument for doubt in the First Meditation
Date: 19 October 2007 10:46

Dear Scott,

Thank you for your email of 10 October, with your University of London essay in response to the question, 'What reasons does Descartes give for doubting all his former beliefs? Are they good reasons?'

If you were answering this question in an examination, you have said enough here to get on the borderline of a 2/i, but there are lots of ways in which this essay can be improved.

First, I cannot stress strongly enough the need to answer the question, and only the question. An examiner reaching your discussion of the cogito would simply stop reading. (Incidentally, the famous quote 'I think therefore I exist' is not in the Meditations, but is taken from his 'Discourse on Method'.)

The discussion of the existence of God and what follows from that are likewise irrelevant.

I can see why you think that it might be necessary to go further than the conclusion of Meditation 1. The question, 'What reasons does Descartes give...' may be seen as ambiguous between:

1. What argument does Descartes give for doubting all his former beliefs?

2. What argument does Descartes give for motivating the attempt to doubt all his former beliefs?

In the second case, you might think that the motive is, after all, to find a way to the cogito and thence to the existence of God and the soul. But in my view this is stretching the meaning of the question way beyond what was intended. The examiner wants to know whether you can (a) give an account of Descartes argument for doubting all his former beliefs and (b) whether you can give a critique of this argument. Both parts of the question should be given roughly equal attention.

Your answer to (a) is far too swift. You haven't looked at the text closely enough. The first thing to note is the peculiar form of the argument. Why doesn't Descartes just go for the jugular and start with the evil demon hypothesis? Why go through the rigmarole of first noting that beliefs that he had previously been certain about have turned out to be false, then questioning perception, then introducing the possibility that he is dreaming, or that he is mad (the last possibility is one that he, arguably, dismisses far too swiftly - a point that you could have made).

Another point to note is Descartes explanation of his own strategy: it is not necessary to question every belief, because it suffices to attack the foundations. He is making an claim here about the structure of empirical knowledge: that it is structured like a building upon 'foundations'.

Why go through all the stages? Descartes envisages a reader who is determined to be sceptical about his project every step of the way. Is it true that a belief that you are certain of might turn out to be false? How can perception be doubted? and so on. This is the reason for the different stages. Each stage in the argument has a reply, but each reply ups the stakes.

For example, one stage that you missed is the reply to the argument that 'my senses have sometimes deceived me'. Descartes gives the common sense response, which at first sight seems fully adequate: the only way we can discover that our senses have deceived us is by taking a closer look. In other words, far from showing that our senses can't be trusted, this shows that we ultimately have to trust our senses.

When we come to the dreaming hypothesis, Descartes does not go so far as to admit that 'to experience dreaming then one must have experiences that are not dreams'. He says that the 'general ideas' must come from somewhere, like extension, number and so on. However, this is a point you could have enlarged on. Do you think it is true that to experience dreaming one must have experiences that are not dreams? So, you would hold that it is logically impossible for there to be a creature which is born but never wakes up, yet experiences a rich dream life. What argument would you give for your view? (I agree with you on this question, but this is just one point where you could have found a lot more words by expanding on the reasons for that counter-claim.)

The evil demon hypothesis, in your words, 'reveals that reality and objects of the external world are only known to us as ideas - all that can be known are ideas.' Your response is that 'This can be questioned however as if what we immediately perceive are external objects and not ideas of the mind then the external world is indeed experienced through our senses.' Here, again I agree with you. But this is precisely one of the main things at stake. How do you prove this? what argument are you going to give against Descartes' claim that things could be just as they are for me now if there were no material objects, no space, just me and my ideas (and the evil demon who causes them)?

I hope you are beginning to see that by focusing more precisely on the question, and looking for arguments to back up each claim that you make, you will find that it is easy to find enough things to say. There is no single 'correct' answer to this question. What you are being asked to do is show that you understand the text in question, that you have thought about the philosophical problems that it raises, and come to conclusions which you are able to defend with arguments.

All the best,