In investigating this problem, the first point that is obvious to an inquirer is, that the change in the centre of gravity from conduct to belief is coincident with the transference of Christianity from a Semitic to a Greek soil. The presumption is that it was the result of Greek influence. It will appear from the Lectures which follow that this presumption is true. Their general subject is, consequently, The Influence of Greece upon Christianity. * * * * * The difficulty, the interest, and the importance of the subject make it incumbent upon us to approach it with caution. It is necessary to bear many points in mind as we enter upon it; and I will begin by asking your attention to two considerations, which, being true of all analogous phenomena of religious development and change, may be presumed to be true of the particular phenomena before us. 1. The first is, that the religion of a given race at a given time is relative to the whole mental attitude of that time. It is impossible to separate the religious phenomena from the other phenomena, in the same way that you can separate a vein of silver from the rock in which it is embedded. They are as much determined by the general characteristics of the race as the fauna and flora of a geographical area are determined by its soil, its climate, and its cultivation; and they vary with the changing characteristics of the race as the fauna and flora of the tertiary system differ from those of the chalk. They are separable from the whole mass of phenomena, not in fact, but only in thought. We may concentrate our attention chiefly upon them, but they still remain part of the whole complex life of the time, and they cannot be understood except in relation to that life. If any one hesitates to accept this historical induction, I will ask him to take the instance that lies nearest to him, and to consider how he could understand the religious phenomena of our own country in our own time—its doubts, its hopes, its varied enterprises, its shifting enthusiasms, its noise, its learning, its estheticism, and its philanthropies—unless he took account of the growth of the inductive sciences and the mechanical arts, of the expansion of literature, of the social stress, of the commercial activity, of the general drift of society towards its own improvement.