The old saying of the two kinds of truth. To the one kind belongs statements so simple and clear that the opposite assertion obviously could not be defended. The other kind, the so-called 'deep truths', are statements in which the opposite also contains deep truth.

A deep truth is a truth so deep that not only is it true but it's exact opposite is also true.

Of course I don't believe in it [pointing to horseshoe on his office wall]. But I understand that it brings you luck whether you believe in it or not.

The opposite of every great idea is another great idea.

We all know your idea is crazy. The question is whether it is crazy enough.

We depend on our words... Our task is to communicate experience and ideas to others. We must strive continually to extend the scope of our description, but in such a way that our messages do not thereby lose their objective or unambiguous character... We are suspended in language in such a way that we cannot say what is up and what is down. The word "reality" is also a word, a word which we must learn to use correctly.

The best weapon of a dictatorship is secrecy, but the best weapon of a democracy should be the weapon of openness.