Key terms and concepts

It is common to read that Descartes was trying to outdo scepticism, to use sceptical arguments to prove scepticism wrong. The whole of Meditation One and the beginning of Meditation Two is presented as an attack on scepticism. This misses the point. Descartes was not particularly troubled by scepticism and didn't see it as a threat. He may have wanted to establish certainty but his target was not scepticism but Aristotelian empiricism.

It is true that Descartes presents a series of sceptical arguments which ultimately fail, or at least so Descartes claims. It is also true that the passage since has been used by philosophers to discuss scepticism. However, neither of these points establish that Descartes' intention was to attack scepticism and to prove that it was wrong.

In the synopsis he says 

In the First Meditation reasons are provided which give us possible grounds for doubt about all things, especially material things, so long as we have no foundations for the sciences other than those which we have had up till now. Although the usefulness of such extensive doubt is not apparent at first sight, its greatest benefit lies in

• freeing us from all our preconceived opinions, and
• providing the easiest route by which the mind may be led away from the senses.

The eventual result of this doubt is to

• make it impossible for us to have any further doubts about what we subsequently discover to be true.

Descartes' focus, what he is attacking, is a reliance on preconceived opinions and the evidence of the senses which he regards as inadequate. Yes, Descartes wants to claim that his own position is immune to 'further doubts' but that is not because he wants to prove scepticism wrong, it is because he wants to show that his position is superior to the empiricist position.

It is true that at the beginning of Meditation II Descartes has the meditator say,

Archimedes used to demand just one firm and immovable point in order to shift the entire earth; so I too can hope for great things if I manage to find just one thing, however slight, that is certain and unshakeable.

But who is this meditator? The first person narrator is not some kind of sceptic who is learning the error of their ways. The narrator, the meditator, is someone who is and has been in thrall to their preconceived opinions, who has relied on the evidence of their senses. Throughout Meditation One the emphasis is on doubting the senses. Even when the meditator considers the possibility of a deceiving God, before he mentions mathematics, he says:

How do I know that he has not brought it about that there is no earth, no sky, no extended thing, no shape, no size, no place, while at the same time ensuring that all these things appear to me to exist just as they do now?

When he introduces the malicious demon there is no mention of mathematics and, once again, the emphasis is on material things

I shall think that the sky, the air, the earth, colours, shapes, sounds and all external things are merely the delusions of dreams which he has devised to ensnare my judgement. I shall consider myself as not having hands or eyes, or flesh, or blood or senses, but as falsely believing that I have all these things.

None of this should be surprising. Recall that in the synopsis he said he wanted to raise 'grounds for doubt about all things, especially material things.'

Writing to Mersenne, Descartes says that the various headings of the six meditations are what he wanted people to mainly notice but adds,

But I think I included many other things besides; and I may tell you, between ourselves, that these six Meditations contain all the foundations of my physics. But please do not tell people, for that might make it harder for supporters of Aristotle to approve them. I hope that readers will gradually get used to my principles, and recognize their truth, before they notice that they destroy the principles of Aristotle. 

When he refers to 'the principles of Aristotle' he may have been referring to more than just Aristotelian empiricism but it presumably includes his empiricism. Remember it was the Aristotelian approach that was summed up in the scholastic maxim, "There is nothing in the intellect that was not first in the senses."

When commenting on the sceptical arguments in the Replies Descartes is dismissive of them, referring to them as reheated leftovers:

Now the best way of achieving a firm knowledge of reality is first to accustom ourselves to doubting all things, especially corporeal things. Although I had seen many ancient writings by the Academics and Sceptics on this subject, and was reluctant to reheat and serve this precooked material, I could not avoid devoting one whole Meditation to it. And I should like my readers not just to take the short time needed to go through it, but to devote several months, or at least weeks, to considering the topics dealt with, before going on to the rest of the book. If they do this they will undoubtedly be able to derive much greater benefit from what follows.

The purpose of doing so is not because scepticism needs to be refuted but because:

All our ideas of what belongs to the mind have up till now been very confused and mixed up with the ideas of things that can be perceived by the senses. This is the first and most important reason for our inability to understand with sufficient clarity the customary assertions about the soul and God.

It is often pointed out that Descartes didn't doubt everything. In the Principles Descartes says:

…when I said that the proposition I am thinking, therefore I exist is the first and most certain of all to occur to anyone who philosophizes in an orderly way, I did not in saying that deny that one must first know what thought, existence and certainty are, and that it is impossible that that which thinks should not exist, and so forth. But because these are very simple notions, and ones which on their own provide us with no knowledge of anything that exists, I did not think they needed to be listed.

Nor, in the Meditations, is it obvious that Descartes clearly doubts his ability to reason reliably, particularly after establishing the cogito. If this were a general attack on scepticism this would be a serious criticism but its absence makes perfect sense if the work is understood to be concerned much more about getting the Aristotelian empiricists to change their way of thinking.

When it was pointed out to Descartes that Augustine had used a very similar argument to his cogito to refute scepticism Descartes replies that to infer existence from the fact one is doubting could have occurred to anyone but he was using the cogito for an entirely different purpose.

TO COLVIUS, 14 NOVEMBER 1640
I am obliged to you for drawing my attention to the passage of St Augustine relevant to my I am thinking, therefore I exist. I went today to the library of this town [Leiden] to read it, and I do indeed find that he does use it to prove the certainty of our existence. He goes on to show that there is a certain likeness of the Trinity in us, in that we exist, we know that we exist, and we love the existence and the knowledge we have. I, on the other hand, use the argument to show that this I which is thinking is an immaterial substance with no bodily element. These are two very different things. In itself it is such a simple and natural thing to infer that one exists from the fact that one is doubting that it could have occurred to any writer. But I am very glad to find myself in agreement with St Augustine, if only to hush the little minds who have tried to find fault with the principle.

We should not go overboard in saying that Descartes was not trying to defeat the sceptics. He was trying to establish something certain and when challenged in the Objections about whether he had taken his method too far and whether it had achieved anything he does reply:

...he did not in fact have any reason to suspect that I had gone astray in any of my assertions, or in the arguments by means of which I became the first philosopher ever to overturn the doubt of the sceptics

There are elements of Meditation One that mirror Montaigne's writing and so, given where Descartes ends up, might be taken as a refutation of Montaigne's scepticism. However, it doesn't seem that this is the primary purpose of Descartes' sceptical method. At the time various groups would use sceptical arguments to challenge their opponents and it appears to be something like this that Descartes is doing. He is using scepticism but addressing the Aristotelians. Responding to objections to the Discourse, Descartes says,

In the Discourse Descartes was reluctant to explain the strongest arguments of the sceptics because, "if weak minds avidly embraced the doubts and scruples that I would have had to propose, they might not be able to understand as fully the arguments by which I tried to remove them."

Where Descartes might more clearly be responding to the threat of scepticism is in his rehabilitation of the external world later on in the Meditations. However, the establishment of certainty is always in the context of rejecting the senses as the most reliable means of gaining knowledge. At the end of the synopsis Descartes says of Meditation Six:

...lastly, there is a presentation of all the arguments which enable the existence of material things to be inferred. The great benefit of these arguments is not, in my view, that they prove what they establish — namely that there really is a world, and that human beings have bodies and so on — since no sane person has ever seriously doubted these things. The point is that in considering these arguments we come to realize that they are not as solid or as transparent as the arguments which lead us to knowledge of our own minds and of God, so that the latter are the most certain and evident of all possible objects of knowledge for the human intellect. Indeed, this is the one thing that I set myself to prove in these Meditations.