A clever child brought up with a foolish one can itself become foolish. Man is so perfectible and corruptible he can become a fool through good sense.

Man…who lives in three places – in the past, in the present, and in the future – can be unhappy if one of these three is worthless. Religion has even added a fourth – eternity.

Never undertake anything for which you wouldn't have the courage to ask the blessings of heaven.

Good taste is either that which agrees with my taste or that which subjects itself to the rule of reason. From this we can see how useful it is to employ reason in seeking out the laws of taste.

Here take back the stuff that I am, nature, knead it back into the dough of being, make of me a bush, a cloud, whatever you will, even a man, only no longer make me.

Sickness is mankind's greatest defect.

Man is a masterpiece of creation if for no other reason than that, all the weight of evidence for determinism notwithstanding, he believes he has free will.