Anyone who seeks for the true causes of miracles, and strives to understand natural phenomena as an intelligent being, and not to gaze at them like a fool, is set down and denounced as an impious heretic.

The safest way for a state is to lay down the rule that religion is comprised solely in the exercise of charity and justice, and that the rights of rulers in sacred, no less than in secular matters, should merely have to do with actions, but that every man should think what he likes and say what he thinks.

Men govern nothing with more difficulty than their tongues, and can moderate their desires more than their words.

Whatever increases, decreases, limits or extends the body's power of action, increases decreases, limits, or extends the mind's power of action. And whatever increases, decreases, limits, or extends the mind's power of action, also increases, decreases, limits, or extends the body's power of action.

Things which are accidentally the causes either of hope or fear are called good or evil omens.

God is the indwelling and not the transient cause of all things.

He who has a true idea, knows at that same time that he has a true idea, nor can he doubt concerning the truth of the thing.