From the first moment of life, men ought to begin learning to deserve to live; and, as at the instant of birth we partake of the rights of citizenship, that instant ought to be the beginning of the exercise of our duty.

No true believer could be intolerant or a persecutor. If I were a magistrate and the law carried the death penalty against atheists, I would begin by sending to the stake whoever denounced another.

Plant and your spouse plants with you; weed and you weed alone.

Cities are the abyss of the human species.

I have never thought, for my part, that man's freedom consists in his being able to do whatever he wills, but that he should not, by any human power, be forced to do what is against his will.

Chemistry... is like the maid occupied with daily civilisation; she is busy with fertilisers, medicines, glass, insecticides ... for she dispenses the recipes.

I do not know is a phrase which becomes us.