The ideal, without doubt, varies, but its enemies, alas, are always the same.

I don't judge a regime by the damning criticism of the opposition, but by the ingenuous praise of the partisan.

Somebody told me I should put a pebble in my mouth to cure my stuttering. Well, I tried it, and during a scene I swallowed the pebble. That was the end of that.

Already at the origin of the species man was equal to what he was destined to become.

Whether man is disposed to yield to nature or to oppose her, he cannot do without a correct understanding of her language

Nothing leads the scientist so astray as a premature truth.

If a given scientist had not made a given discovery, someone else would have done so a little later. Johann Mendel dies unknown after having discovered the laws of heredity: thirty-five years later, three men rediscover them. But the book that is not written will never be written. The premature death of a great scientist delays humanity; that of a great writer deprives it.