We have no organ at all for knowledge, for truth: we know (or believe or imagine) precisely as much as may be useful in the interest of the human herd, the species: and even what is here called usefulness is in the end only a belief, something imagined and perhaps precisely that most fatal piece of stupidity by which we shall one day perish.

Here the ways of men part: if you wish to strive for peace of soul and pleasure, then believe; if you wish to be a devotee of truth, then inquire.

Belief in the truth commences with the doubting of all those truths we once believed.

A man with a grain of faith in God never loses hope, because he ever believes in the ultimate triumph of Truth.

Beyond a doubt truth bears the same relation to falsehood as light to darkness.

What then in the last resort are the truths of mankind? They are the irrefutable errors of mankind.