René Descartes Quotes

I could not possibly exist with the nature I actually have, that is, one endowed with the idea of God, unless there really is a God; the very God, I mean, of whom I have an  idea.

I will suppose then, not that there is a supremely good God, the source of truth; but that there is an evil spirit, who is supremely powerful and intelligent, and does his utmost to deceive me.

Some years ago now I observed the multitude of errors that I had accepted as true in my earliest years, and the dubiousness of the whole superstructure I had since then reared on them; and the consequent need of making a clean sweep for once in my life, and beginning again from the very foundations, if  I would establish some secure and lasting result in science.

I could take it as a general rule that whatever we conceive very clearly and very distinctly is true.

I think, therefore I am.