Summary

At the start of the chapter, Descartes is gripped with deep doubts and worries that it will be impossible to find any certain knowledge. He compares the certain knowledge he is hoping for with Archimedes’ fixed and immovable point; just as Archimedes showed that with just a single immovable point and a lever, one could in theory lift even the world, Descartes thinks he can recover all his knowledge of the external world if he just finds a single piece of “certain and immovable” knowledge (46). The piece of knowledge Descartes arrives at is this: he exists. Since he has doubted everything, then there must be somebody who doubts, namely him. Even if there is an evil demon deceiving him, still he must exist, because otherwise there would be nobody for the demon to deceive. Simply the thought “I am, I exist” is enough...