Do not believe in anything simply because you have heard it. Do not believe in anything simply because it is spoken and rumored by many. Do not believe in anything simply because it is found written in your religious books. Do not believe in anything merely on the authority of your teachers and elders. Do not believe in traditions because they have been handed down for many generations. But after observation and analysis, when you find that anything agrees with reason and is conducive to the good and benefit of one and all, then accept it and live up to it.

Greek philosophy seems to have met with something with which a good tragedy is not supposed to meet, namely, a dull ending.

Philosophy stands in the same relation to the study of the actual world as masturbation to sexual love.

The philosophers have only interpreted the world, in various ways: the point, however, is to change it.

He who despises painting has no love for the philosophy in nature.

Skepticism is a virtue in history as well as in philosophy.