Theories pass. The frog remains.

It is sometimes important for science to know how to forget the things she is surest of.

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.

One kills a man, one is an assassin; one kills millions, one is a conqueror; one kills everybody, one is a god.

Truth is always served by great minds, even if they fight it.

A few great minds are enough to endow humanity with monstrous power, but a few great hearts are not enough to make us worthy of using it.

The biologist passes. The frog stays the same.