One must be truthful with oneself about one's own motives, especially if one is to survive in the world. It takes rigor, and it takes courage.

People who are upset about something ruminate on it whenever they get a chance; they are constantly drawn back to their own unhappy tale as if it were a horror story left open on a table.

Every idea I get I have to deny, that's my way of testing it.

We prove what we want to prove, and the real difficulty is to know what we want to prove.

There is a future that makes itself and a future we make. The real future is composed of both.

Nothing is more dangerous than an idea when it is the only one you have.

The most difficult thing in the world is to say thinkingly what everybody says without thinking.