tate upon reason is the keynote of Plato's politics.

And this gives us, too, the clue to the problem, what is the end of
the State? Why should there be a State at all? This does not mean, how
has the State arisen in history? We are not in search of the cause,
but of the reason, or end, of the State. The end of all life is
wisdom, virtue, and knowledge. The unassisted individual cannot reach
these ends. It is only by the State that they can be brought down from
heaven to earth. The end of the State is thus the virtue and happiness
(not pleasure) of the citizens. And since this is only possible {227}
through education, the State's primary function is educational.

Since the State is to be founded upon reason, its laws must be
rational, and rational laws can only be made by rational men,
philosophers. The rulers must be philosophers. And since the
philosophers are few, we must have an aristocracy, not of birth, or of
wealth, but of intellect. The first operative principle of the State
is reason, the second is force. For it is not to be expected that the
irrational masses will willingly submit to rational laws. They must be
compelled. And since the work of the world must go on, the third
operative principle will be labour. Plato believed in the principle of
division of labour. Only he can excel at any occupation whose life is
devoted to it. Hence to the three operative principles correspond
three classes, castes, or professions. Reason is embodied in the
philosopher-rulers, force in the warriors, labour in the masses. This
division of the functions of the State is based upon the threefold
division of the soul. To the rational soul correspond the
philosopher-rulers, to the nobler half of the mortal soul the
warriors, to the appetitive soul the masses. Consequently the four
cardinal virtues belong to the State through the functioning of the
three classes. The virtue of the philosopher-rulers is wisdom, of the
warriors courage, of the masses, temperance. The harmonious
co-operation of all three produces justice.

The rulers must not cease to be philosophers. Most of their time must
be spent in the study of the Ideas, philosophy, and only a portion in
the affairs of government. This is rendered possible by the system of
taking turns. Those who are not at any particular time {228} engaged
upon government retire into thought. The duty of the warriors is the
protection of the State, both against its external enemies, and
again