Perfect numbers like perfect men are very rare.

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.

At last I will devote myself sincerely and without reservation to the general demolition of my opinions.

Common sense is the most widely shared commodity in the world, for every man is convinced that he is well supplied with it.

We call infinite that thing whose limits we have not perceived, and so by that word we do not signify what we understand about a thing, but rather what we do not understand.

Conquer yourself rather than the world.