ey were good Platonists, they had a
conception of the purpose and system of human life in society, which
perhaps excuses all, and more than all, the defects of their biology.
Any survey, however brief, of the political theory of the Middle Ages
will show at once its Platonic character and its incessant impulse
towards the achievement of unity.

III

To mediaeval thought, as to Plato, the unity of society is an organic
unity, in the sense that each member of society is an organ of the whole
to which he belongs, and discharges a function at once peculiar to
himself and necessary to the full life of the whole. Monasticism, so
often misrepresented, attains its true meaning in the light of this
conception. The monk is a necessary organ of Christian society,
discharging his function of prayer and devotion for the benefit not of
himself solely, or primarily, but rather of every member of that
society. He prays for the sins of the whole world, and by his prayer he
contributes to the realization of the end of the world, which is the
attainment of salvation. In the same way the conception of a treasury of
merits, afterwards perverted in the system of indulgences, belongs to an
organic theory and practice of society. The merits which Christ and the
saints have accumulated are a fund for the use of the whole of Christian
society, a fund on which any member can draw for his own salvation, just
because each is fitly joined and knit together with all the rest in a
single body for the attainment of a single purpose. But we need not take
isolated instances of the Platonism of mediaeval thought. The whole
basic conception of a system of estates, which recurs everywhere in
mediaeval life, is a Platonic conception. The estates of clergy,
baronage, and commons are the Platonic classes of guardians,
auxiliaries, and farmers. The Platonic creed of [Greek: to auton
prattein] ('Do thine own duty') is the Christian creed of 'doing my
duty in that state of life to which it shall please God to call me'. The
Middle Ages are full of a spontaneous Platonism, and inspired by an
_anima naturaliter Platonica_. The control which the mediaeval clergy
exercised over Christian society in the light of divine revelation
repeats the control which the guardians of Plato were to exercise over
civic society in the light of the Idea of the Good. The communism of the
mediaeval monastery is reminiscent of the communism of the Platonic
barracks. And if there are