Wherever progress is to ensue, deviating natures are of greatest importance.

Every achievement, every step forward in knowledge, is the consequence of courage, of toughness towards oneself, of sincerity to oneself

Those people have no real interest in a science who only begin to get excited about it when they themselves have made discoveries in it.

For what purpose humanity is there should not even concern us: why you are here, that you should ask yourself: and if you have no ready answer, then set for yourself goals, high and noble goals, and perish in pursuit of them!

That which needs to be proved cannot be worth much.

The small force that it takes to launch a boat into the stream should not be confused with the force of the stream that carries it along: but this confusion appears in nearly all biographies.

A living being seeks, above all, to discharge its strength. Life is will to power.