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.

There is less harm to be suffered in being mad among madmen than in being sane all by oneself.

All things must be examined, debated, investigated without exception and without regard for anyone's feelings... We must run roughshod over all these ancient puerilities, overturn the barriers that reason never erected, give back to the arts and sciences the liberty that is so precious to them.

Mankind have banned the Divinity from their presence; they have relegated him to a sanctuary; the walls of the temple restrict his view; he does not exist outside of it.

Only passions, and great passions, can raise the soul to great things. Without them there is no sublimity, either in morals or in creativity. Art returns to infancy, and virtue becomes small-minded.

Scepticism is the first step towards truth.

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