Theological religion is the source of all imaginable follies and disturbances. It is the parent of fanaticism and civil discord; it is the enemy of mankind.

One great use of words is to hide our thoughts.

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 with books as with the fires of our grates, everybody borrows a light from his neighbor to kindle his own, which in turn is communicated to others, and each partakes of all.

The Holy Roman Empire is neither Holy, nor Roman, nor an Empire.

When one man speaks to another man who doesn't understand him, and when a man who's speaking no longer understands, it's metaphysics.

Very often, say what you will, a knave is only a fool.