Man is a masterpiece of creation, if only because no amount of determinism can prevent him from believing that he acts as a free being.

If we thought more for ourselves we would have very many more bad books and very many more good ones.

Bad writers are those who try to express their own feeble ideas in the language of good ones.

I believe that man is in the last resort so free a being that his right to be what he believes himself to be cannot be contested.

It not seldom happens that in the purposeless rovings and wanderings of the imagination we hunt down such game as can be put to use by our purposeful philosophy in its well-ordered household.

Just as we outgrow a pair of trousers, we outgrow acquaintances, libraries, principles, etc., at times before they're worn out and times - and this is the worst of all - before we have new ones.

All mathematical laws which we find in Nature are always suspect to me, in spite of their beauty. They give me no pleasure. They are merely auxiliaries. At close range it is all not true.