Book 5.8
It is natural that a man should first incur an obligation, and then that he should return gratitude for it; a debtor cannot exist without a creditor, any more than a husband without a wife, or a son without a father; someone must give in order that some one may receive. Just as no one carries himself, although he moves his body and transports it from place to place; as no one, though he may have made a speech in his own defence, is said to have stood by himself, or erects a statue to himself as his own patron; as no sick man, when by his own care he has regained his health, asks himself for a fee; so in no transaction, even when a man does what is useful to himself, need he return thanks to himself, because there is no one to whom he can return them. Though I grant that a man can bestow a benefit upon himself, yet at the same time that he gives it, he also receives it; though I grant that a man may receive a benefit from himself, yet he receives it at the same time that he gives it. The exchange takes place within doors, as they say, and the transfer is made at once, as though the debt were a fictitious one; for he who gives is not a different person to he who receives, but one and the same. The word "to owe" has no meaning except as between two persons; how then can it apply to one man who incurs an obligation, and by the same act frees himself from it? In a disk or a ball there is no top or bottom, no beginning or end, because the relation of the parts is changed when it moves, what was behind coming before, and what went down on one side coming up on the other, so that all the parts, in whatever direction they may move, come back to the same position. Imagine that the same thing takes place in a man; into however many pieces you may divide him, he remains one. If he strikes himself, he has no one to call to account for the insult; if he binds himself and locks himself up, he cannot demand damages; if he bestows a benefit upon himself, he straightway returns it to the giver. It is said that there is no waste in nature, because everything which is taken from nature returns to her again, and nothing can perish, because it cannot fall out of nature, but goes round again to the point from whence it started. You ask, "What connection has this illustration with the subject?" I will tell you. Imagine yourself to be ungrateful, the benefit bestowed upon you is not lost, he who gave it has it; suppose that you are unwilling to receive it, it still belongs to you before it is returned. You cannot lose anything, because what you take away from yourself, you nevertheless gain yourself. The matter revolves in a circle within yourself; by receiving you give, by giving you receive.