If we define it as the attitude and reaction of a human being conditioned by his knowledge of the immediate materials and his conception of the ultimate powers of the universe, its scope is so extended as to include the ideas of the atheists and agnostics as well as the crude conceptions of lower races and those systems of piety and worship conventionally regarded as religions by civilized peoples.  More than this:  we cannot regard the total reaction of a thinking being as essentially different in ultimate value from the attitudes toward their worlds of animals lower than man.  The situation of a well-trained sheep dog is one of pastures and fences and gates, of rain and sunshine, of sheep, and of a master whose voice is to be obeyed.  What the dog may do is partly determined by what it finds in its world of animate and inanimate things.  Although the animal’s “conception” of such things must be far simpler than a human being’s, nevertheless its life is lived in reaction to all of its surroundings as they are presented to its cerebral apparatus by the proper organs.  So in the human case, conduct is directly affected by the living and lifeless objects of a total human situation, the only difference being that reflective consciousness and reasoned interpretation have their share in determining the assumed attitude in ways that seem to have no counterparts as such in the mental lives of lower animals.  But whether or not the similarity between human religion and lower organic reaction be admitted,—­and the admission is one that greatly facilitates an understanding of evolution in this field,—­the general resemblance of all religions in fundamental character at least must be accepted.

Another general feature of religious systems is their complexity.  The essential elements of all of them are few indeed, as we shall see at a later point; they are beliefs regarding ultimate powers, human responsibility to such powers, and future existence.  These have taken one specific form or another in various lines of racial evolution, but aside from their own changes they have gathered about them many other articles of creed relating to other departments of thought and life.  Ethical rules of conduct are so added, as in the Hebrew religion where the idea of Jehovah involves God the Ruler and Judge who imposes and administers the laws of right living.  Social customs are almost invariably intertwined with religious views, among savages as well as among the more advanced Mohammedans whose rules relating to family organization form an integral part of the whole cult.  The emotional elements play a large part in some cases, in the fanatical creeds of the Dervish and Mahdist and in the “revivals” under nearer observation.  In Greek cosmology and worship, aesthetics figured to a large degree.  Temperamental and other psychological characteristics have profound effects upon religions, which we may illustrate by such extreme examples as the austerities of New England and Scotch Presbyterianism and the contrasted liberties of the natural religions of tropical races.  But all of these accessory elements belong to other well-defined departments, some of which have already been considered, and among the materials of their proper divisions they find their interpretation and historical explanation in evolution.  It is with the basic elements themselves that we are now concerned.