One cannot conceive anything so strange and so implausible that it has not already been said by one philosopher or another.

It is only prudent never to place complete confidence in that by which we have even once been deceived.

—Rene Descartes

The first precept was never to accept a thing as true until I knew it as such without a single doubt.

—Rene Descartes

It is not enough to have a good mind. The main thing is to use it well.

—Rene Descartes

I think; therefore I am.

—Rene Descartes

It is not enough to have a good mind; the main thing is to use it well.

—Rene Descartes

Philosophy is a battle against the bewitchment of our intelligence by means of language.

—Ludwig Wittgenstein

Philosophy consists very largely of one philosopher arguing that all others are jackasses. He usually proves it, and I should add that he also usually proves that he is one himself.

—H. L. Mencken

Who you are isn't tied solely to what you say, even though it may feel that way to you now.

—Diane Ackerman

There is nothing so absurd but some philosopher has said it.

—Cicero

This is patently absurd; but whoever wishes to become a philosopher must learn not to be frightened by absurdities.

—Bertrand Russell