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Summary: Meditations on First Philosophy (page 2)

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However, a counter-argument appears: isn't the body more knowable than the mind or thought?


The body is visible, we can touch it, manipulate it, carry out experiments on it.
Thought on the other hand is immaterial and its nature seems mysterious.

Doesn't Descartes therefore make a mistake in seeking a certain truth in "the thing that thinks"? Should this not be sought in matter?


To invalidate this argument, Descartes resorts in the Meditations on First Philosophy to the famous argument of the wax. When we examine this piece of pure matter, we detect certain characteristics: a certain length, a consistency, this or that colour, etc. However, if you heat it, all these characteristics, which seemed to be firmly anchored in the thing, disappear. The solid wax becomes liquid, its colour changes, as does its weight or diameter.

We had therefore not discovered an indubitable evidence. It is therefore illusory to look for a truth of this kind in matter and bodies.

Perception, which seems to give us a direct and immediate access to the truth of things, is therefore deceptive.


On the other hand, this truth can be discovered, not by perception but by understanding. Indeed, in solid wax and molten wax, there remain elements that do not change: wax, for example, always has a certain extent, a certain flexibility, and so on. These are invariant elements of any kind of material object, and we get the idea of them by abstraction. Thus it is by abstracting the common point of different extents that we obtain the general notion of extent.

This is how the understanding, unlike perception, grasps a truth in the thing. Descartes here prefigures the distinction that Locke will make between first and second qualities, in his Essay Concerning Human Understanding.

He uses a second example, that of the hats observed from the top of his window to show that the understanding grasps a truth that escapes perception: the passers-by wearing these hats.

Descartes concludes that indubitable truth lies on the side of the mind, rather than the body:

From the fact that bodies themselves are not properly known by the senses or the faculty of imagination, but by the understanding alone, I see clearly that there is nothing that is easier to know than my mind 1.


In Book III of the Meditations on First Philosophy, Descartes seeks to deduce certain truths that would be contained in the cogito. From the cogito, Descartes has already deduced truths about the self, as something that thinks.

For Descartes, we can deduce certain truths about God from the truths he has uncovered about the self.

In other words: from the cogito he deduced the self, and from the self he will deduce God.

This is a crucial point because until we know whether God exists, and whether he is not deliberately deceiving us about everything, we are not sure of any truth about the world.

To do this he will start from the Ego as a "thing that thinks", this indubitable truth. Now this thing that thinks contains ideas. He distinguishes between ideas "born with me", "made by myself", and finally "foreign, coming from outside".


How can we be sure that the latter refer to an external reality? Indeed, we can assume in me a spontaneous power to produce these ideas without help from external things, as in the case of dreaming.

Descartes proposes a way of determining whether a particular idea does indeed refer to an external reality. This involves noting that some ideas participate in more degrees of being or perfection than others 2. He takes the example of the ideas of substance and accident. The former has more reality than the latter.

If we accept this, then it should be noted that the idea of God occupies a privileged position:

That by which I conceive a sovereign, eternal, infinite, immutable God, certainly has in itself more objective reality than those for which finite substances are represented to me 3.

1 p.108
2 p.120
3 Ibid.