A man bestows a benefit upon me: I receive it just as he wished it to be received: then he gets at once what he wanted, and the only thing which he wanted, and therefore I have proved myself grateful. After this it remains for me to enjoy my own resources, with the addition of an advantage conferred upon me by one whom I have obliged; this advantage is not the remainder of an imperfect service, but an addition to a perfected service. 2 For example, Phidias makes a statue. Now the product of an art is one thing, and that of a trade is another. It is the business of the art to make the thing which he wished to make, and that of the trade to make it with a profit. Phidias has completed his work, even though he does not sell it. The product, therefore, of his work is threefold: there is the con............