Properly speaking, we learn from those books only that we cannot judge. The author of a book that I am competent to criticise would have to learn from me.

The unnatural, that too is natural.

There is nothing in the world more pitiable than an irresolute man, oscillating between two feelings, who would willingly unite the two and who does not perceive that nothing can unite them

What life half gives a man, posterity gives entirely.

We can stand only a certain amount of unhappiness; anything beyond that annihilates us or passes us by, leaving us apathethetic.

Our passions are true phoenixes; as the old burn out the new straight rise up from the ashes.

Die Mathematiker sind eine Art Franzosen. Spricht man zu ihnen, so übersetzen sie alles in ihre eigene Sprache, und so wird es alsobald etwas ganz anderes. Mathematicians are a kind of Frenchmen. Whenever you say anything or talk to them, they translate it into their own language, and right away it is something completely different.