We must know where to doubt, where to feel certain, where to submit. He who does not do so, understands not the force of reason.

To find recreation in amusement is not happiness.

The last function of reason is to recognize that there are an infinity of things which surpass it.

The greater intellect one has, the more originality one finds in men. Ordinary persons find no difference between men.

It is not from space that I must seek my dignity, but from the government of my thought. I shall have no more if I possess worlds. By space the universe encompasses and swallows me up like an atom; by thought I comprehend the world.

If we regulate our conduct according to our own convictions, we may safely disregard the praise or censure of others.

Once your soul has been enlarged by a truth, it can never return to its original size.