What we have just been saying shows us the correct path. Through psychology and biology, sociology can become attached to the general body of science; and in so doing it can both receive and give. Since man is but a single species of organism, and, biologically speaking, a very young one; since moreover he presents a peculiar type of organization, it is clear that the broad principles underlying physiology and evolution can best be studied on other organisms and later applied to man. On the other hand, man is the highest existing organism; thus a study of the causes to which he owes his pre-eminence will be important as adding to and crowning the principles derived from non-human biology. Furthermore, not only are man’s mental powers on a different level from those of other animals, but psychology can at present make by far its greatest contributions by a study of human mind, so that the psychological side of biology will for the present derive its chief information from man. Our first affair, therefore, is to see in what important respects man is qualitatively unlike the rest of the organic world; then to investigate what general rules or principles apply equally to him and to the others; and finally to see what corrections, so to speak, must be made before these principles can be applied to the one or to the other. The qualitative difference between man and other organisms is a cardinal fact with orthodox biology has tended to slur over or to neglect, whereas philosophy has too often tried to magnify it unduly so as to make man frankly incommensurable with his lower relatives, a creature not only unique but disparate. Man is obviously and undoubtedly an organism of the same general nature as other organisms. He possesses the same general system of organs, working in the same way as a dog, a horse, a bird, a crocodile, or a frog; he passes through the same type of developmental cycle; he is built on the same detailed plan as other mammals; and numerous indications betray his descent from a particular branch of the mammalian stock. But in his mode of life and type of social organization he is unique. All detailed comparisons between the communities of man and those of bees and ants are as unprofitable in the working-out as they are easy in the making. It is futile to direct the sluggard or any other human being to the ant, since the whole physical and psychical construction of ants is different from that of man, the whole organization of their communities from that of his. His mode of life is unique because his psycho-neural mechanism is built on a new plan, new modes of connection between parts of the brain being associated with new possibilities of mind. Let us briefly run over the biologically most important points in which he differs from the lower organisms.