“If ever anybody dedicated his whole life to the “enthusiasm for truth and justice” using this phrase in the good sense it was Diderot.”

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.

Instinct guides the animal better than the man. In the animal it is pure, in man it is led astray by his reason and intelligence.

Poetry must have something in it that is barbaric, vast and wild.

We are constantly railing against the passions; we ascribe to them all of man’s afflictions, and we forget that they are also the source of all his pleasures.

We are now in the mountains and they are in us, kindling enthusiasm, making every nerve quiver, filling every pore and cell of us.

I began to realize how important it was to be an enthusiast in life.

You can do anything if you have enthusiasm.

Success consists of going from failure to failure without loss of enthusiasm.

Enthusiasm is a supernatural serenity.

The enthusiasm of a woman’s love is even beyond the biographer’s.

What I do best is share my enthusiasm.

Enthusiasm is the steam that drives the engine.