(by paragraph divisions)
1.) Descartes tells us he has wanted to make this argument for his whole adult life, but that he waited until he was at the height of his intellectual powers and had set aside the most favorable time for meditation in order to bring together all the considerations of his philosophical life. He is not brainstorming or setting down hypotheses for further reflection (e.g. “So, uh, an evil deceiver…whutaya think?”). This is a reflective, structured, systematic account of problems that a very great mind has thought about for a very long time.
When reading the Mediations, it’s easy to get dazzled by singular ideas (methodological doubt, the evil deceiver, the cogito, piece of wax) and to lose sight of how systematic and structured the argument is.
2.) While the first sentence gets the more attention – i.e. that Descartes will doubt all that admits of some doubt – the end of the paragraph is just as important: Descartes is going to consider the foundations of what he believes. One of the dominant themes in the first meditation is just how hard it is to keep ones consideration fixed on foundations.
3-5) The senses deceive at least sometimes, and when anything deceives us sometimes, we’re hesitant to trust them anytime. We certainly wouldn’t count on them in important matters, and what Descartes is discussing is such a case. Descartes immediately raises his own objection to it, namely that it seems obvious that some sensations are more certain than others: the size of the sun might be doubtful, but the fact that I am moving my hand is not. His first response is to this is that an insane person would have just the same evidence he has for moving his hand. The theme is more developed in the following paragraph.
The dream argument: Descartes allows that we can often tell the difference between a dream and a waking state: what he denies is that there are any certain marks by which we can do so. There are differences in ambiance to the waking state and the dream state, but it is hard to catch a definitive, concrete criterion to tell the difference. We come up short when we try to explain how the dream state must differ from the waking one.
6-8) First responses to the dream argument: Even when we dream or imagine, it is not the case that everything is made up. We take some things for granted, and so it would seem that the reality of these things cannot be doubted. For example, a imagining satyrs involves taking human torsos for granted; and it seems to be impossible to imagine or dream anything without taking colors and shapes for granted. Descartes concedes that whether he wakes or sleeps, three and two make five. He has a response to this which strikes exactly the right note: namely that in mathematics we “scarcely inquire whether or not these things are existent”. The response is sharp and to my mind fatal: if anything is doubtful, it is whether mathematical things really exist, at any rate, a large part of the certitude of mathematics arises from the fact that “to exist” means “I can define its function” or “I can construct it whenever I want”, which is certainly not the sort of existence that one has in mind when he wonders whether the world exists.
(One could, however, reconstruct most of modern science if we stopped reading here. Mathematics is certain, and we can understand nature to the extent that “to exist” means the same thing as it means in mathematics. What we can make, or what can play a functional role in an algebraic expression exists. This is science.)
9-10) A general argument that is is possible to doubt absolutely anything. The argument in developed in two paragraphs:
Thesis: A human being must admit it is possible that he be deceived about absolutely anything
1.) Either man was created by an omnipotent being, or he was not.
2.) If by an omnipotent being, it is possible that this being deceives him about everything.
3.) If not, man comes to be from some other process (antecedent necessary causes, chance, a being of limited power) But then it is also possible that he be deceived about everything, for there is no reason to think that these causes could have given rise to a being that could know the truth of things. Therefore he must also admit the possibility that he is deceived about everything.
11.) Descartes insists that it is more probable and more reasonable to follow common sense and take most sensations at face value. Illusions are relatively rare, frequently contrived, and usually of little significance in science. In the practical order, illusions are even less significant. Descartes is intentionally and forcibly twisting himself with this doctrine of doubt, and it is difficult for him to hold the position for too long. But he is doing it with an eye to seeing the foundation of thought.
12.) The evil deceiver: for all of his evocative power, the evil deceiver is an afterthought – he is a metaphor to describe a course of action that is already decided upon. There is even a tension in calling him an evil deceiver: Descartes is far more critical of the sort of life one falls into when he forgets the evil deceiver. The inability to sustain a universal doubt is called “indolence” and is compared to a slave who is dreaming of his liberty. Taking the world at face value is an impediment to seeing its foundation or basis. That is a philosophical thesis that deserves a fuller hearing.