Nothing leads the scientist so astray as a premature truth.

Theories pass. The frog remains.

Falsity cannot keep an idea from being beautiful; there are certain errors of such ingenuity that one could regret their not ranking among the achievements of the human mind.

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

To say of men that they are bad is to say they are worse than we think we are, or worse than the ideal man whose image we have built up on the basis of a certain few.

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

Literature: proclaiming in front of everyone what one is careful to conceal from one's immediate circle