The original in conduct, that is to say, resistiveness to the voice of the herd, will be suppressed by natural selection; the wolf which does not follow the impulses of the herd will be starved; the sheep which does not respond to the flock will be eaten.

Again, not only will the individual be responsive to impulses coming from the herd, but he will treat the herd as his normal environment. The impulse to be in and always to remain with the herd will have the strongest instinctive weight. Anything which tends to separate him from his fellows, as soon as it becomes perceptible as such, will be strongly resisted.[34]

According to sociologists of this school, public opinion, conscience, and authority in the state rest upon the natural disposition of the animal in the herd to conform to "the decrees of the herd."

Conscience, then, and the feelings of guilt and of duty are the peculiar possessions of the gregarious animal. A dog and a cat caught in the commission of an offence will both recognize that punishment is coming; but the dog, moreover, knows that he has done wrong, and he will come to be punished, unwillingly it is true, and as if dragged along by some power outside him, while the cat's sole impulse is to escape. The rational recognition of the sequence of act and punishment is equally clear to the gregarious and to the solitary animal, but it is the former only who understands that he has committed a crime, who has, in fact, the sense of sin.[35]

The concepts upon which this explanation of society rests is homogeneity. If animals or human beings act under all circumstances in the same way, they will act or seem to act, as if they had a common purpose. If everybody follows the crowd, if everyone wears the same clothes, utters the same trite remarks, rallies to the same battles cries and is everywhere dominated, even in his most characteristically individual behavior, by an instinctive and passionate desire to conform to an external model and to the wishes of the herd, then we have an explanation of everything characteristic of society—except the variants, the nonconformists, the idealists, and the rebels. The herd instinct may be an explanation of conformity but it does not explain variation. Variation is an important fact in society as it is in nature generally.

Homogeneity and like-mindedness are, as explanations of the social behavior of men and animals, very closely related concepts. In "like response to like stimulus," we may discern the beginning of "concerted action" and this, it is urged, is the fundamental social fact. This is the "like-mindedness" theory of society which has been given wide popularity in the United States through the writings of Professor Franklin Henry Giddings. He describes it as a "developed form of the instinct theory, dating back to Aristotle's aphorism that man is a political animal."

Any given stimulus may happen to be felt by more than one organism, at the same or at different times. Two or more organisms may respond to the same given stimulus simultaneously or at different times. They may respond to the same given stimulus in like or in unlike ways; in the same or in different degrees; with like or with unlike promptitude; with equal or with unequal persistence. I have attempted to show that in like response to the same given stimulus we have the beginning, the absolute origin, of all concerted activity—the inception of every conceivable form of co-operation; while in unlike response, and in unequal response, we have the beginning of all those processes of individuation, of differentiation, of competition, which in their endlessly varied relations to combination, to co-operation, bring about the infinite complexity of organized social life.[36]

Closely related, logically if not historically, to Giddings' conception of "like-mindedness" is Gabriel Tarde's conception of "imitation." If for Giddings "like response to like stimulus" is the fundamental social fact, for Tarde "imitation" is the process through which alone society exists. Society, said Tarde, exists in imitation. As a matter of fact, Tarde's doctrine may be regarded as a corollary to Giddings'. Imitation is the process by which that like-mindedness, by which Giddings explains corporate action, is effected. Men are not born like-minded, they are made so by imitation.

This minute inter-agreement of minds and wills, which forms the basis of the social life, even in troublous times—this presence of so many common ideas, ends, and means, in the minds and wills of all members of the same society at any given moment—is not due, I maintain, to organic heredity, which insures the birth of men quite similar to one another, nor to mere identity of geographical environment, which offers very similar resources to talents that are nearly equal; it is rather the effect of that suggestion-imitation process which, starting from one primitive creature possessed of a single idea or act, passed this copy on to one of its neighbors, then to another, and so on. Organic needs and spiritual tendencies exist in us only as potentialities which are realizable under the most diverse forms, in spite of their primitive similarity; and, among all these possible realizations, the indications furnished by some first initiator who is imitated determine which one is actually chosen.[37]