ual_

Just as Plato's theory of knowledge begins with a negative portion,
designed to refute false theories of what truth is, so does his theory
of morals begin with a negative portion, intended to refute false
theories of what virtue is. These two negative departments of Plato's
philosophy correspond in every way. As he was then engaged in showing
that knowledge is not perception, as Protagoras thought, so he now
urges that {218} virtue is not the same as pleasure. And as knowledge
is not mere right opinion, neither is virtue mere right action. The
propositions that knowledge is perception, and that virtue is
pleasure, are indeed only the same principle applied to different
spheres of thought. For the Sophists whatever appeared true to the
individual was true for that individual. This is the same as saying
that knowledge is perception. For the Sophists, again, whatever
appeared right to the individual was right for that individual. This
is the same as saying that it is right for each man to do whatever he
pleases. Virtue is defined as the pleasure of the individual. This
consequence of the Sophistic principles was drawn both by many of the
Sophists themselves, and later by the Cyrenaics.

As these two propositions are thus in fact only one principle, what
Plato has said in refutation of the former provides also his
refutation of the latter. The theory that virtue is pleasure has the
same destructive influence upon morals as the theory that knowledge is
perception had upon truth. We may thus shortly summarize Plato's
arguments.

(1) As the Sophistic theory of truth destroys the objectivity of
truth, so the doctrine that virtue is the pleasure of the individual
destroys the objectivity of the good. Nothing is good in itself.
Things are only good for me or for you. There results an absolute
moral relativity, in which the idea of an objective standard of
goodness totally disappears.

(2) This theory destroys the distinction between good and evil. Since
the good is whatever the individual pleases, and since the pleasure of
one individual is the {219} displeasure of another, the same thing is
both good and evil at the same time, good for one person and evil for
another. Good and evil are therefore not distinct. They are the same.

(3) Pleasure is the satisfaction of our desires. Desires are merely
feelings. This theory, therefore, founds morality upon feeling. But an
objective morality cannot be founded upon what is pe