Of the factors which determine the kind of thinking one does, we know enough to say that there were two things certain of early mankind. We know the kind of thinking of which he was capable, and we have a general notion of the material existing for thinking. Speaking of one of these early ancestors of ours, Professor Arthur Keith says, "Piltdown man saw, heard, felt, thought and dreamt much as we do," that is, there was the same _kind_ of brain at work that is at work now. And that much we could be sure of by going no farther back than the savages of to-day. But as size of brain is not everything, we are warranted in saying that the brain was of a relatively simple type, while the knowledge of the world which existed, and which gives us the material for thinking, was of a very imperfect and elementary character. There was great ignorance, and there was great fear. From these two conditions, ignorance and fear, sprang the gods. Of that there is no doubt whatever. There is scarcely a work which deals with the life of primitive peoples to-day that does not emphasize that fact. Consciously or unconsciously it cannot avoid doing so. Long ago a Latin writer hit on this truth in the well-known saying, "Fear made the gods," and Aristotle expressed the same thing in a more comprehensive form by saying that fear first set man philosophizing. The undeveloped mind troubles little about things so long as they are going smoothly and comfortably. It is when something painful happens that concern is awakened. And all the gods of primitive life bear this primal stamp of fear. That is why religion, with its persistent harking back to the primitive, with its response to the "Call of the Wild" still dwells upon the fear of the Lord as a means of arousing a due sense of piety. The gods fatten on fear as a usurer does upon the folly of his clients, and in both cases the interest demanded far outweighs the value of the services rendered. At a later stage man faces his gods in a different spirit; he loses his fear and examines them; and gods that are not feared are but poor things. They exist mainly as indisputable records of their own deterioration.