Theology, from the beginning, has had no other task; at all events, it has had no task more arduous or pressing than that of reconciling these two data. There have always been two tendencies amongst theologians corresponding to two families of minds: the _Idealist_ tendency--that of Origen and his emulators, which puts the emphasis en ideas and constructs a religious metaphysic or gnosis, which of necessity rationalises dogma, and for which history is but a temporary envelope, a sort of external and sensible illustration; and the _Realist_ tendency, represented by the genius of Tertullian, which, obeying an opposite instinct, materialises ideas, gives an anthropomorphic body to everything, even to God, deifies phenomena, and changes contingent history into an eternal metaphysic. From these two tendencies, perpetual and parallel, have issued the two solutions given by Rationalism and by Orthodoxy to the problem as to the essence of Christianity. The first finds that essence in a few simple truths of reason or of consciousness, which are of all time and all lands, and which impose themselves on every man by their own natural evidence. Jesus of Nazareth was the preacher and the martyr of these truths; but it is clear that His personality is no more essential to Christianity than that of Plato is to his philosophy. Only, mind, in thus severing itself from Christ the Christian Religion ceases to be positive and becomes an abstract and dead doctrine; it loses its religious pith and power.