Give me extension and motion and I will construct the universe.

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.

If ... it is not in my power to arrive at the knowledge of any truth, I may at least do what is in my power, namely, suspend judgement.

Every man is indeed bound to do what he can to promote the good of others, and a man who is of no use to anyone is strictly worthless.

For each of us there is a set limit to our intellectual powers which we cannot pass.

... regard this body as a machine which, having been made by the hand of God, is incomparably better ordered than any machine that can be devised by man, and contains in itself movements more wonderful than those in any machine. ... it is for all practical purposes impossible for a machine to have enough organs to make it act in all the contingencies of life in the way in which our reason makes us act.

It is not enough to have a good mind. The main thing is to use it well.