about it, one, at least, is making an intellectual error, just as much as if the disagreement were a
scientific one on some matter of fact.
The difference between Plato and Thrasymachus is very important, but for the historian of
philosophy it is one to be only noted, not decided. Plato thinks he can prove that his ideal
Republic is good; a democrat who accepts the objectivity of ethics may think that he can prove the
Republic bad; but any one who agrees with Thrasymachus will say: "There is no question of
proving or disproving; the only question is whether you like the kind of State that Plato desires. If
you do, it is good for you; if you do not, it is bad for you. If many do and many do not, the
decision cannot be made by reason, but only by force, actual or concealed." This is one of the
issues in philosophy that are still open; on each side there are men who command respect. But for
a very long time the opinion that Plato advocated remained almost undisputed.
It should be observed, further, that the view which substitutes the consensus of opinion for an
objective standard has certain consequences that few would accept. What are we to say of
scientific innovators like Galileo, who advocate an opinion with which few agree, but finally win
the support of almost everybody? They do so by means of arguments, not by emotional appeals or
state propaganda or the use of force. This implies a criterion other than the general opinion. In
ethical matters, there is something analogous in the case of the great religious teachers. Christ
taught that it is not wrong to pluck ears of corn on the Sabbath, but that it is wrong to hate your
enemies. Such ethical innovations obviously imply some standard other than majority opinion, but
the standard, whatever it is, is not objective fact, as in a scientific question. This problem is a
difficult one, and I do not profess to be able to solve it. For the present, let us be content to note it.
Plato's Republic, unlike modern Utopias, was perhaps intended to be actually founded. This was
not so fantastic or impossible as it might naturally seem to us. Many of its provisions, including
some that we should have thought quite impracticable, were actually realized at Sparta. The rule
of philosophers had been attempted by Pythagoras, and in Plato's time Archytas the Pythagorean
was politically influential in Taras (the modern Taranto) when Plato visited Sicily and southern
Italy. It was a common practice for cities to employ a sage