There is a consideration in favour of this method which is in entire harmony with that which arises from the nature of the evidence. It is, that the changes that took place were gradual and at first hardly perceptible. It would probably be impossible, even if we were in possession of ampler evidence, to assign a definite cause and a definite date for the introduction of each separate idea. For the early years of Christianity were in some respects like the early years of our lives. It has sometimes been thought that those early years are the most important years in the education of all of us. We learn then, we hardly know how, through effort and struggle and innocent mistakes, to use our eyes and our ears, to measure distance and direction, by a process which ascends by unconscious steps to the certainty which we feel in our maturity. We are helped in doing go, to an incalculable degree, by the accumulated experience of mankind which is stored up in language; but the growth is our own, the unconscious development of our own powers. It was in some such unconscious way that the Christian thought of the earlier centuries gradually acquired the form which we find when it emerges, as it were, into the developed manhood of the fourth century. Greek philosophy helped its development, as language helps a child; but the assimilation of it can no more be traced from year to year than the growth of the body can be traced from day to day. We shall begin, therefore, by looking at the several groups of facts of the age in which Christianity grew, and endeavour, when we have looked at them, to estimate their influence upon it. We shall look at the facts which indicate the state of education: we shall find that it was an age that was penetrated with culture, and that necessarily gave to all ideas which it absorbed a cultured and, so to speak, scholastic form. We shall look at the facts which indicate the state of literature: we shall find that it was an age of great literary activity, which was proud of its ancient monuments, and which spent a large part of its industry in endeavouring to interpret and to imitate them. We shall look at the facts which indicate the state of philosophy: we shall find that it was an age in which metaphysical conceptions had come to occupy relatively the same place which the conceptions of natural science occupy among ourselves; and that just as we tend to look upon external things in their chemical and physical relations, so there was then, as it were, a chemistry and physics of ideas.