But behind the external evolution of a given religion, its modes of worship, its ministers, its doctrines, lie more complicated questions. What causes shaped these acts and moulded these beliefs? What elements of race are to be discerned in them? How can we account for the diversities between the religions of peoples belonging to a common stock, like those of India and those of ancient Italy? What have been the effects of climate, of the struggle with alien peoples and new environment? How does the food-supply influence {30} the formation of religious ideas? What contacts have been felt with other races, and what positive loans or more impalpable influences have passed from one side to the other? We, find here in _hierology_, the science of "the Sacred," an analogue to the reasoning which accounts for the distribution of land and water, the rise of mountain ranges and the sculpture of valleys and river-beds out of the stratification of the earth's crust, and builds up a science of geology; or which traces the results of migration upon peoples, the consequences of inter-marriage with other tribes, the disastrous issues of war, surveys the immense variety of causes which have contributed to new developments of racial energy, and arranges this knowledge in the science of ethnology. And, lastly, the values of these facts must be estimated. How far can they be accepted as expressing the reality of the Unseen Power, and man's relation to it? Hierology may explain how men have developed certain practices or framed certain beliefs; to determine their reasonableness is the task of the philosophy of religion or _hierosophy_.[4] [4] These three terms have been suggested by Count Goblet d'Alviella, of Brussels. The study of "Comparative Religion" assumes that religion is already in existence. It deals with actual usages, which it places side by side to see what light they can throw upon each other. It leaves the task of {31} formulating definitions to philosophy. It is not concerned with origins, and does not project itself into the prehistoric past where conjecture takes the place of evidence. An old miracle-play directed Adam to pass across the stage "going to be created." Whether religion first appeared in the cultus of the dead, or only entered the field after the collapse of a reign of magic which had ceased to satisfy man's demands for help, or was born of dread and desired to keep its gods at a distance, only remotely affects the process of discovering and examining the resemblances of its forms, and interpreting the forces without and within which have produced them. The sphere of speculation has its own attractions, but in this little book an attempt will be made to keep to facts.