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 differences between the society imagined by Plato and the society envisaged by the mediaeval Church, these differences only show that the mediaeval Church was trying to raise Platonism to a higher power, and to do so in the light of conceptions which were themselves Greek, though they belonged to a Greece posterior to the days of Plato.  These conceptions—­which were cherished by Stoic thinkers; which penetrated into Roman Law; and which from Roman Law flowed into the teaching and theory of the early fathers of the Church—­are mainly two.  One is the conception of human equality; the other, and correlative, conception is that of a single society of all the human race.  The equality of men, and the universality of the city of God in which they are all contained, are conceptions which were no less present to Marcus Aurelius than they were to St. Augustine.  They are conceptions which made the instinctive Platonism of the mediaeval Church even more soaring than that of Plato.  While the Republic of Plato had halted at the stage of a civic society, the respublica Christiana of the Middle Ages rose to the height of a single humana civilitas.  While Plato had divided the men of his Republic into classes of gold and silver and bronze, and had reserved the ecstasy of the aspect of the divine Idea for a single class, the mediaeval Church opened the mystery of the Mass and the glory of the fruition of God to all believers, and, if she believed in three estates, nevertheless gathered the three in one around the common altar of the Redeemer.  Serfdom might still remain, and find tolerance, in the economic working of society; but in the Church herself, assembled together for the intimate purposes of her own life, there was ‘neither bond nor free’.

The prevalence of Realism, which marks mediaeval metaphysics down to the end of the thirteenth century, is another Platonic inheritance, and another impulse to unity.  The Universal is, and is a veritable thing, in which the Particular shares, and acquires its substance by its degree of sharing.  The One transcends the Many; the unity of mankind is greater than the differences between men; and the university of mortal men, as Ockham writes, is one community.  If there be thus one community, and one only, some negative