“There are three principal means of acquiring knowledge, observation of nature, reflection, and experimentation. Observation collects facts; reflection combines them; experimentation verifies the result of that combination.”

If you want me to believe in God, you must make me touch him.

All abstract sciences are nothing but the study of relations between signs.

No man has received from nature the right to give orders to others. Freedom is a gift from heaven, and every individual of the same species has the right to enjoy it as soon as he is in enjoyment of his reason.

Evil always turns up in this world through some genius or other.

Morals are in all countries the result of legislation and government; they are not African or Asian or European: they are good or bad.

One may demand of me that I should seek truth, but not that I should find it.

Every man has his dignity. I’m willing to forget mine, but at my own discretion and not when someone else tells me to.

Patriotism is an ephemeral motive that scarcely ever outlasts the particular threat to society that aroused it.

Posterity for the philosopher is what the other world is for the religious man.

No man has received from nature the right to command his fellow human beings.

He whom we call a gentleman is no longer the man of Nature.

We are far more liable to catch the vices than the virtues of our associates.

I feel, I think, I judge; therefore, a part of organized matter like me is capable of feeling, thinking, and judging.

Watch out for the fellow who talks about putting things in order! Putting things in order always means getting other people under your control.

It is very important not to mistake hemlock for parsley, but to believe or not believe in God is not important at all.

The best mannered people make the most absurd lovers.