The mind effortlessly and automatically takes in new ideas, which remain in limbo until verified or rejected by conscious, rational analysis.

A person has two passions for love and abhorrence. A big disposition to excessiveness has just a love, because it is more ardent and stronger.

All is to be doubted.

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

Mathematics is a more powerful instrument of knowledge than any other that has been bequeathed to us by human agency.

Except our own thoughts, there is nothing absolutely in our power.

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.