Desire awakens only to things that are thought possible.

The principal use of prudence, of self-control, is that it teaches us to be masters of our passions, and to so control and guide them that the evils which they cause are quite bearable, and that we even derive joy from them all.

There is nothing more ancient than the truth.

Variant: When it is not in our power to follow what is true, we ought to follow what is most probable.

To live without philosophizing is in truth the same as keeping the eyes closed without attempting to open them.

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

I accept no principles of physics which are not also accepted in mathematics.