A second element in the social consciousness, and, perhaps, that which has most of all characterized it through the larger period of its growth, is the strong sense of the mutual influence of men--that we are all "members one of another." 1. _Contributing Lines of Thought._--It is worth seeing how firmly planted the idea is. Several lines of thought have united to induce men to emphasize--perhaps even to over-emphasize--this way of thinking of society. The influence of natural science, in the first place, has been inevitably in this direction. Its root idea of the universality of law forces upon one the thought of a world which is a _coherent_ whole, a unity with universal forces in it, in which every part is inextricably connected with every other. So, too, the acceptance of the theory of evolution has led science to regard the whole history of the physical universe as an organic growth. Psychology, also, with its present-day emphasis, in Baldwin and Royce, upon the constant presence and fundamental character of _imitation_, and its insistence upon the still more fundamental impulsiveness of consciousness which Dewey believes underlies imitation,[3] is really proclaiming exactly this element of the social consciousness. And the whole assertion by the later psychology of the unity of man--mind and body, and of the complex intertwining of all the functions of the mind, is in closest harmony with a similar view of society. Philosophy, too, is exerting all along a half-unconscious pressure toward the thought of the organic unity of society. That philosophy may exist at all, it must start from the assumption of a universe, a real unity of truth, and its problem is to find a _discerned_ unity. It knows no unrelated being, and, consequently, whether it theoretically accepts the formulation or not, it must admit that, as a matter of fact, to be is to be in relations. It asserts as a universal fact, what natural science and psychology both affirm in their own respective spheres, the concrete relatedness of all. It cannot well deny the same thought when applied to society. Its repeated attempts, moreover, to conceive all as a developing unity, and the profound influence of the analogy of the organism upon its history, both further sustain the organic view of society. Christianity, as well, has been a powerful factor in this direction from the beginning, for it really first gave the Idea of Humanity.[4] 2. _The Threefold Form of the Conviction._--Sustained, now, by all these movements in natural science, psychology, philosophy, and Christianity, this thought of the mutual influence of men has taken three forms: that mutual influence is inevitable, isolation impossible; that mutual influence is desirable, isolation to be shunned; that mutual influence is indispensable, isolation blighting.