A sketch is generally more spirited than a picture,

I picture the vast realm of the sciences as an immense landscape scattered with patches of dark and light. The goal towards which we must work is either to extend the boundaries of the patches of light, or to increase their number. One of these tasks falls to the creative genius; the other requires a sort of sagacity combined with perfectionism.

Skepticism is the first step on the road to philosophy.

Gaiety is a quality of ordinary men. Genius always presupposes some disorder in the machine.

Justice is the first virtue of those who command, and stops the complaints of those who obey

No man has received from nature the right to command his fellow human beings.