order could not be upheld especially in the subdivisions of a science. Although Spencer appeared to have the best of this argument, there is, nevertheless, some ground for holding to the general principle expressed in Comte's theory. Following the three-fold division of the sciences, which I have given above, it seems clear that the sciences dealing with the environment developed before those dealing with life, and the latter group developed in advance of those dealing with society. This is, moreover, the order of their present degree of advancement as well as their early development.
The development of the sciences seems, in fact, to be influenced by two conditions, first the immediate interest of men, and secondly the complexity of the phenomena investigated. These two conditions account sufficiently for the relative growth of different branches of knowledge at different times. In early stages of civilization man's attention was concentrated chiefly upon the physical environment. To get a food supply and other necessaries of life more easily, to protect themselves against their enemies, to provide for the needs of the dead, and to satisfy the demands of the gods, were all important problems which stimulated a knowledge of the environment and brought at least a practical working knowledge of the simplest laws of mathematics, astronomy and physics, together with some knowledge of minerals, and of animal and vegetable life. The phenomena of life, the desire to live indefinitely and to overcome disease, attracted attention almost as soon as problems of the environment. But life is much stranger and more complicated than those objects of nature which may be readily examined, and a positive knowledge of the phenomena of life was much more slowly acquired. The heavenly bodies and other natural objects which were so far removed that their character was not easily perceived, and living things which were so complex that they were not understood, remained objects of superstition and speculation much longer than inanimate objects close at hand. The persistence of religious superstition delayed considerably knowledge of human anatomy and disease, favoring rather the pursuit of astrology and alchemy. The anatomical studies of the Alexandrian school were in opposition to the prevalent sentiments of the time, and the Mohammedan religion hindered the study of biology, as compared with other sciences among the Arabians. Biology, therefore, developed later than the physical sciences, not because it did not attract attention, but because it was too complicated to be understood in an early stage of mental development. The social sciences, on the other hand, developed last, both because they did not attract attention at an early period and because they dealt with complex phenomena. It is true, as Spencer points out, that some practical knowledge of social organization must have appeared at a very early time and conditioned, in a sense, all forms of progress. But this kind