Many centuries have passed since the time of St. Thomas Aquinas; and the element of tragedy in the study of the history of religions for the Christian theologian is that he is forced to admit that never again has there been a time when the unification of aspiration and knowledge has been so completely realised by organised Christianity. It was not long after this time that epoch-making changes were made, first in the domain of astronomy and afterwards in other sciences. They have revolutionised human knowledge. Nor have human aspirations stayed where they were. The ideal of justice which men see to-day is different and assuredly better than that of a thousand years ago. It extends beyond the sphere of the law-courts to every branch of human life. But the doctrines of the Church remain formulated according to the knowledge and aspirations of the past. The divergence between knowledge and theological statement has become more and more obvious every year. There has been no synthetic progress in theology since the time of St. Thomas Aquinas,[3] for it is impossible for the student of history to feel that the Reformation can be regarded as a synthesis. Indeed it seems ominously like the first step in that disintegration which has always been {12} the last stage in the story of each religion. It is absolutely certain that the world will once again some day achieve what it has often had and often lost--the closer approximation of knowledge and aspiration--so that its religious system may satisfy the soul of the saint without disgusting the intellect of the scholar. What is uncertain is whether this achievement will be made by any form of organised Christianity or is reserved for some movement which cannot at present be recognised.[4] To trace the whole of these syntheses would be a reasonable programme for many volumes. These lectures are limited to the discussion of the evolution of the first and the beginning of the second--that is to say, the change of Christianity from a Jewish sect to a sacramental cult and the beginning of the movement which introduced Greek metaphysics into its theology.