Friendship is the source of the greatest pleasures, and without friends even the most agreeable pursuits become tedious.

Man can sin against nature in two ways. First, when he sins against his specific rational nature, acting contrary to reason. In this sense, we can say that every sin is a sin against man's nature, because it is against man's right reason.

Future contingents cannot be certain to us, because we know them as such. They can be certain only to God whose understanding is in eternity above time. Just as a man going along a road does not see those who come after him; but the man who sees the whole road from a height sees all those who are going along the road at the same time.

If a thing can be done adequately by means of one, it is superfluous to do it by means of several; for we observe that nature does not employ two instruments [if] one suffices.

Mistakes are made on two counts: an argument is either based on error or incorrectly developed.

Without the suitable conditions life could not exist. But both life and its conditions set forth the operations of inscrutable Power. We know not its origin; we know not its end. And the presumption, if not the degradation, rests with those who place upon the throne of the universe a magnified image of themselves, and make its doings a mere colossal imitation of their own. Wonder was the motive that led people to philosophy ... wonder is a kind of desire in knowledge. It is the cause of delight because it carries with it the hope of discovery.

Art is right reason in the doing of work.