Scepticism is the first step towards truth.

How old the world is! I walk between two eternities.... What is my fleeting existence in comparison with that decaying rock, that valley digging its channel ever deeper, that forest that is tottering and those great masses above my head about to fall? I see the marble of tombs crumbling into dust; and yet I don't want to die!

Instinct guides the animal better than the man. In the animal it is pure, in man it is led astray by his reason and intelligence.

They mistake the first manifestations of a developing sexual nature for the voice of God calling them to Himself; and it is precisely when nature is inciting them that they embrace a fashion of life contrary to nature's wish.

If you want me to believe in God, you must make me touch him.

How easy it is to tell tales!

Those who fear the facts will forever try to discredit the fact-finders.