Because reason...is the only thing that makes us men, and distinguishes us from the beasts, I would prefer to believe that it exists, in its entirety, in each of us.

The first precept was never to accept a thing as true until I knew it as such without a single doubt.

Each problem that I solved became a rule, which served afterwards to solve other problems.

He lives well who is well hidden.

Even if I were to suppose that I was dreaming and whatever I saw or imagined was false, yet I could not deny that ideas were truly in my mind.

On the one hand I have a clear and distinct idea of myself, in so far as I am a thinking, non-extended thing; and on the other hand I have a distinct idea of body, in so far a this is simply an extended, non-thinking thing. And, accordingly, it is certain that I am really distinct from my body, and exist without it.

There is nothing so strange and so unbelievable that it has not been said by one philosopher or another.