The reading of all good books is like a conversation with the finest minds of past centuries.

In the matter of a difficult question it is more likely that the truth should have been discovered by the few than by the many.

Science is practical philosophy.

Conquer yourself rather than the world.

[About Pierre de Fermat] It cannot be denied that he has had many exceptional ideas, and that he is a highly intelligent man. For my part, however, I have always been taught to take a broad overview of things, in order to be able to deduce from them general rules, which might be applicable elsewhere.

I did not imitate the skeptics who doubt only for doubting's sake, and pretend to be always undecided; on the contrary, my whole intention was to arrive at a certainty, and to dig away the drift and the sand until I reached the rock or the clay beneath.

I am accustomed to sleep and in my dreams to imagine the same things that lunatics imagine when awake.