The facts which I have collected and exposed, incomplete as the statement is, may justify what was said at the outset of the inquiry, that the aboriginal idea of purity has struck deep roots in the soil on which much of our ethical thought and feeling, many of our legal and religious institutions, have grown and developed. The concept, owing perhaps to its immemorial continuity of life and deep primeval instinctiveness, if the word may pass, is liable to fantastic exaggerations. It has sometimes proved itself an insurmountable barrier to moral and legal progress. When it has crystallised into a hard “pharisaic” form, it has arrested and imprisoned the life of a hitherto progressive people. On the other hand, though its innate quality, so to speak, is never secular-utilitarian, its contributions to our civilisation have been, as we have seen, of inestimable service. It has engendered the modern horror of murder {162} and bloodshed, and the ideal of the chaste life: we owe to it in great degree the delicate sensitiveness of spiritually gifted characters. For good and for evil, it has been an instinctive religious force more potent than any other of these in the mental evolution of man. LECTURE IV. THE EVOLUTION OF PRAYER FROM LOWER TO HIGHER FORMS {163} There is no part of the religious service of mankind that so clearly reveals the various views of the divine nature held by the different races at the different stages of their development as the formulæ of prayer, or reflects so vividly the material and psychologic history of man. The historic material at our disposal is unfortunately modern, not reaching back, that is to say, to a period earlier than some four thousand years before Christ; but this can be supplemented, as usually happens, by the evidence gathered from the lower societies, as well as by the observation of practices that frequently accompany and are very closely blended with prayer even in the higher religions, {164} and that we may with confidence believe to have descended from an immemorial antiquity. The question as to the origin of prayer is one of great difficulty and of the deepest significance for the history and philosophy of religion; for it inevitably involves the questions concerning the origin of the belief in a personal divinity, concerning the relation of magic to religion, of the spell-ritual which commands or constrains to a prayer-ritual of humiliation and entreaty. Even if I had an original and matured judgment to put before you on questions of such importance, a single lecture would be a very inadequate space for its exposition.[164.1] Therefore, though I may indicate, I will not attempt in this lecture to decide on, the question of origin. I will content myself with arranging the phenomena according as they appear from our point of view to belong to a lower stratum of religion or a higher; such an {165} arrangement begs no question, and agrees