For the feeling of pleasure is not at all a necessity, but the accompaniment of certain natural needs—hunger, thirst, cold, marriage. If, then, it were possible to drink without it, or take food, or beget children, no other need of it could be shown. For pleasure is neither a function, nor a state, nor any part of us; but has been introduced into life as an auxiliary, as they say salt was to season food. But when it casts off restraint and rules the house, it generates first concupiscence, which is an irrational propension and impulse towards that which gratifies it; and it induced Epicurus to lay down pleasure as the aim of the philosopher. Accordingly he deifies a sound condition of body, and the certain hope respecting it. For what else is luxury than the voluptuous gluttony and the superfluous abundance of those who are abandoned to self-indulgence? Diogenes writes significantly in a tragedy:—