nal ends.

Aristotle's mixed constitution springs from a recognition of sectional
interests in the state. For the proper relation between the claims of
"virtue," wealth, and numbers is to be based not upon their relative
importance in the good life, but upon the strength of the parties which
they represent. The mixed constitution is practicable in a state where
the middle class is strong, as only the middle class can mediate between
the rich and the poor. The mixed constitution will be stable if it
represents the actual balance of power between different classes in the
state. When we come to Aristotle's analysis of existing constitutions,
we find that while he regards them as imperfect approximations to the
ideal, he also thinks of them as the result of the struggle between
classes. Democracy, he explains, is the government not of the many but
of the poor; oligarchy a government not of the few but of the rich.
And each class is thought of, not as trying to express an ideal, but as
struggling to acquire power or maintain its position. If ever the class
existed in unredeemed nakedness, it was in the Greek cities of the
fourth century, and its existence is abundantly recognised by Aristotle.
His account of the causes of revolutions in Book V. shows how far were
the existing states of Greece from the ideal with which he starts.
His analysis of the facts forces him to look upon them as the scene
of struggling factions. The causes of revolutions are not described as
primarily changes in the conception of the common good, but changes in
the military or economic power of the several classes in the state. The
aim which he sets before oligarchs or democracies is not the good life,
but simple stability or permanence of the existing constitution.

With this spirit of realism which pervades Books IV., V., and VI.
the idealism of Books I., II., VII., and VIII. is never reconciled.
Aristotle is content to call existing constitutions perversions of
the true form. But we cannot read the Politics without recognising
and profiting from the insight into the nature of the state which is
revealed throughout. Aristotle's failure does not lie in this, that he
is both idealist and realist, but that he keeps these two tendencies
too far apart. He thinks too much of his ideal state, as something to
be reached once for all by knowledge, as a fixed type to which actual
states approximate or from which they are perversions. But if we are to
think o