It is otherwise in biology, or the organic section of cosmology. Here we still find miracles set up in opposition to the law of substance, and the transgression of natural laws by supernatural forces. The belief in miracles of this kind, which pure reason calls superstition, is still very wide-spread--much more prevalent than is usually thought. For my part, I hold that superstition and unreason are the worst enemies of the human race, while science and reason are its greatest friends. Hence it is our duty and task to attack the belief in miracles wherever we find it, in the interest of the race. We have to prove that the reign of natural law extends over the whole world of phenomena as far as we can reach it. A general survey of the history of faith on the one hand and of science on the other clearly shows that the advance of the latter has always been accompanied by an increasing knowledge of fixed natural laws and the shrinking of superstition into an ever-lessening area. To-day we convince ourselves of this by an impartial examination of mental culture at the various stages of civilization. For this purpose I take the four chief stages of mental development which Fritz Schultze has given in his _Physiology of Uncivilized Races_, and Alexander Sutherland in his work, _On the Origin and Growth of the Moral Instinct_: 1, savages; 2, barbarians; 3, civilized races; 4, educated races (_cf._ chapter i.). The mental life of savages rises little above that of the higher mammals, especially the apes, with which they are genealogically connected. Their whole interest is restricted to the physiological functions of nutrition and reproduction, or the satisfaction of hunger and thirst in the crudest animal fashion. Without fixed habitation, constantly struggling for existence, they live on the raw produce of nature--fruits, the roots of wild plants, and the animals they fish in the water or catch on land. Their intelligence moves within the narrowest bounds, and one can no more (or no less) speak of their reason than of that of the more intelligent animals. Of art and science there is no question. Their impulse to discover causes is satisfied with the simplest association of phenomena which have a merely external connection, but no intimate relation to each other. Thus arises their _fetichism_, that irrational trust in fetiches which Fritz Schultze has traced to four distinct causes: their false estimate of the value of an object, their anthropomorphic conception of nature, the imperfect association of their ideas, and the strength of their emotions, especially hope and fear. Any favorite object, a stone or a bone, may work miracles as a fetich and exercise all kinds of good or evil influence, and is therefore honored, feared, and worshipped. At first the worship was paid to the invisible spirit that dwelt in the particular object; but it was often transferred afterwards to the dead object itself. Among the different savage races the belief in