HAVING PROPOSED to himself the aim of demolishing all of his opinions, the meditator accepts a maxim for belief:
Reason now leads me to think that I should hold back my assent from opinions which are not completely certain and indubitable just as carefully as I do from those which are patently false. So for the purpose of rejecting all my opinions, it will be enough if I find in each of them at least some reason for doubt.(2:12; AT 7:18)
This is a puzzling maxim for assent, but before I consider it, I want to sketch out some features of the Academic and Pyrrhonian skepticism with which Descartes must have been familiar.1 I will then return in chapter 3 to the meditator and his maxim.
There are three features of ancient skepticism that I want to bring out. The first is that ancient skeptics were not directly concerned with knowledge or certainty or with the grounds for doubt that would make us withdraw claims to knowledge or certainty. Rather, they were directly____________________