Book 6.20

"According to this," argues our opponent, "you are under no obligation to the sun or the moon; for they do not move for your sake alone." No, but since they move with the object of preserving the balance of the universe, they move for my sake also, seeing that I am a fraction of the universe. Besides, our position and theirs is not the same, for he who does me good in order that he may by my means do good to himself, does not bestow a benefit upon me, because he merely makes use of me as an instrument for his own advantage; whereas the sun and the moon, even if they do us good for their own sakes, still cannot do good to us in order that by our means they may do good to themselves, for what is there which we can bestow upon them?