playing at ball it is something to catch the ball cleverly and
carefully, but a man is not called a good player unless he can
handily and quickly send back the ball which he has caught." This
analogy is imperfect; and why? Because to do this creditably
depends upon the movement and activity of the body, and not upon
the mind: and an act of which we judge entirely by the eye, ought
to be all clearly displayed. But if a man caught the ball as he
ought to do, I should not call him a bad player for not returning
it, if his delay in returning it was not caused by his own fault.
"Yet," say you, "although the player is not wanting in skill,
because he did one part of his duty, and was able to do the other
part, yet in such a case the game is imperfect, for its perfection
lies in sending the ball backwards and forwards." I am unwilling to
expose this fallacy further; let us think that it is the game, not
the player that is imperfect: so likewise in the subject which we
are discussing, the thing which is given lacks something, because
another equal thing ought to be returned for it, but the mind of
the giver lacks nothing, because it has found another mind equal to
itself, and as far as intentions go, has effected what it wished.

XXXIII. 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. [Footnote: Nothing
is wanted to make a benefit, conferred from good motives, perfect:
if it is returned, the gratitude is to be counted as net profit.]
For example, Phidias makes a statue. Now the product of an art is