Each religion, so dear to those whose life it sanctifies, and fulfilling so necessary a function in the society that has adopted it, necessarily contradicts every other religion, and probably contradicts itself.

Our character ... is an omen of our destiny, and the more integrity we have and keep, the simpler and nobler that destiny is likely to be.

One's friends are that part of the human race with which one can be human.

Society is like the air, necessary to breathe but insufficient to live on.

The passions grafted on wounded pride are the most inveterate; they are green and vigorous in old age.

There are three traps that strangle philosophy: The church, the marriage bed, and the professor's chair.

Nothing is so irrevocable as mind.