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.