What is called an acute knowledge of human nature is mostly nothing but the observer's own weaknesses reflected back from others.

Be attentive, feel nothing in vain, measure and compare: this is the whole law of philosophy.

The American who first discovered Columbus made a bad discovery.

One has to do something new in order to see something new.

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.

What we have to discover for ourselves leaves behind in our mind a pathway that can be used on another occasion.

In every man there is something of all men.