People must have renounced, it seems to me, all natural intelligence to dare to advance that animals are but animated machines.... It appears to me, besides, that such people can never have observed with attention the character of animals, not to have distinguished among them the different voices of need, of suffering, of joy, of pain, of love, of anger, and of all their affections. It would be very strange that they should express so well what they could not feel.

If you want to know who controls you, look at who you are not allowed to criticize.

He who is involved in ecstasies and visions, who takes dreams for reality, and his own imagination for prophesy, is a fanatical novice of great hope and promise, and will soon advance to the higher stage and kill men for the love of God.

It is not enough to be exceptionally mad, licentious and fanatical in order to win a great reputation; it is still necessary to arrive on the scene at the right time.

Language is a very difficult thing to put into words.

If God did not exist, he would have to be invented.

I believe that there never was a creator of a philosophical system who did not confess at the end of his life that he had wasted his time. It must be admitted that the inventors of the mechanical arts have been much more useful to men that the inventors of syllogisms. He who imagined a ship towers considerably above him who imagined innate ideas.