A nation which thinks that it is belief in God and not good law which makes people honest does not seem to me very advanced.

All things must be examined, debated, investigated without exception and without regard for anyone's feelings.

When shall we see poets born? After a time of disasters and great misfortunes, when harrowed nations begin to breathe again. And then, shaken by the terror of such spectacles, imaginations will paint things entirely strange to those who have not witnessed them.

Superstition is more injurious to God than atheism.

The Christian religion teaches us to imitate a God that is cruel, insidious, jealous, and implacable in his wrath.

I picture the vast realm of the sciences as an immense landscape scattered with patches of dark and light. The goal towards which we must work is either to extend the boundaries of the patches of light, or to increase their number. One of these tasks falls to the creative genius; the other requires a sort of sagacity combined with perfectionism.

What is this world? A complex whole, subject to endless revolutions. All these revolutions show a continual tendency to destruction; a swift succession of beings who follow one another, press forward, and vanish; a fleeting symmetry; the order of a moment. I reproached you just now with estimating the perfection of things by your own capacity; and I might accuse you here of measuring its duration by the length of your own days.