Morality is neither rational nor absolute nor natural. World has known many moral systems, each of which advances claims universality; all moral systems are therefore particular, serving a specific purpose for their propagators or creators, and enforcing a certain regime that disciplines human beings for social life by narrowing our perspectives and limiting our horizons.

Do not do to others what angers you if done to you by others.

It is never right to do wrong or to requite wrong with wrong, or when we suffer evil to defend ourselves by doing evil in return.

I do not believe in immortality of the individual, and I consider ethics to be an exclusively human concern with no superhuman authority behind it.

Good literature proceeds from men of natural probity, and since one ought rather to praise the inception than the result, you should give greater praise to a man of probity unskilled in letters than to one skilled in letters but devoid of probity.

We have never stopped sin by passing laws; and in the same way, we are not going to take a great moral ideal and achieve it merely by law.