I would rather be a devil in alliance with truth, than an angel in alliance with falsehood.

Christianity has in fact long vanished, not only from the reason but also from the life of mankind, and it is nothing more than a fixed idea.

To theology, ... only what it holds sacred is true, whereas to philosophy, only what holds true is sacred.

The first and highest law must be the love of man to man. Homo homini Deus est - this is the supreme practical maxim, this is the turning point of the world's History.

Faith is essentially intolerant ... essentially because necessarily bound up with faith is the illusion that one's cause is also God's cause.

Wherever morality is based on theology, wherever the right is made dependent on divine authority, the most immoral, unjust, infamous things can be justified and established.

As we expand our knowledge of good books, we shrink the circle of men whose company we appreciate.