If it were true what in the end would be gained? Nothing but another truth. Is this such a mighty advantage? We have enough old truths still to digest, and even these we would be quite unable to endure if we did not sometimes flavor them with lies.

Reason now gazes above the realm of the dark but warm feelings as the Alpine peaks do above the clouds. They behold the sun more clearly and distinctly, but they are cold and unfruitful.

Pain warns us not to exert our limbs to the point of breaking them. How much knowledge would we not need to recognize this by the exercise of mere reason.

If another Messiah was born he could hardly do so much good as the printing-press.

One is rarely an impulsive innovator after the age of sixty, but one can still be a very fine orderly and inventive thinker. One rarely procreates children at that age, but one is all the more skilled at educating those who have already been procreated, and education is procreation of another kind.

Diogenes, filthily attired, paced across the splendid carpets in Plato's dwelling. Thus, said he, do I trample on the pride of Plato. Yes, Plato replied, but only with another kind of pride.

Do not say hypothesis, and even less theory: say way of thinking.