Remorse sleeps in the atmosphere of prosperity.

Whence do I get my rules of conduct? I find them in my heart. Whatever I feel to be good is good. Whatever I feel to be evil is evil. Conscience is the best of casuists.

There are two things to be considered with regard to any scheme. In the first place, Is it good in itself? In the second, Can it be easily put into practice?

To renounce liberty is to renounce being a man, to surrender the rights of humanity and even its duties. For he who renounces everything no indemnity is possible. Such a renunciation is incompatible with man's nature; to remove all liberty from his will is to remove all morality from his acts.

At sixteen, the adolescent knows about suffering because he himself has suffered, but he barely knows that other beings also suffer.

Force does not constitute right... obedience is due only to legitimate powers.

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