The link that binds man to man is called the social instinct, though perhaps it would be better to call it the group of social instincts. The link is one of feeling, primarily, though it has associated with it, in an indissoluble way, purpose and action. The existence of the social instinct is undisputed; its explanation is varied and ranges from the mystical to the evolutionary. For the mystical (which crops out in Bergson, Butler and even in Galton), the unity of life is its basis, and there is a sort of recognition of parts formerly united but now separate individuals. This does not explain hate, racial and individual. The evolutionary aspect has received its best handling in recent years in Trotter's "The Herd," where the social instincts are traced in their relation to human history. One writer after another has placed as basic in social instinct, sympathy, imitation, suggestibility and the recognition of "likeness." These are merely names for a spreading of emotion from one member of a group to another, for a something that makes members of the group teachable and makes them wish to teach; that is back of the wish to conform and help and has two sets of guiding forces, reward and its derivative praise; punishment and its derivative blame. Perhaps the term "derivative" is not correct, and perhaps praise and blame are primary and reward and punishment secondary. So eminent a philosopher as the elder Mill declared the distribution of praise and blame is the greatest problem of society." This view of the place of praise and blame in the organization of character and in directing the efforts and activity of men is hardly exaggerated. From birth to death the pleasure of reward and praise and the pain of punishment and blame are immensely powerful human motives. It is true that now and then individuals seek punishment and blame, but this is always to win the favor of others or of the most important observer of men's actions,--God, The child is trained through the effect of reward and punishment, praise and blame; and these are used to set up, on the one hand, habits of conduct, and on the other an inner mentor and guide called Conscience. It may be true that conscience is innate in its potentialities, but whether that is so or not, it is the teaching and training of the times or of some group that gives to conscience its peculiar trend in any individual case. And before a child has any inward mentor it depends for its knowledge of right and wrong upon the efforts of its parents, their use of praise-reward and blame-punishment; it reacts to these measures in accordance with the strength and vigor of its social instincts and in accordance with its fear of punishment and desire for reward. The feelings of duty and the prickings of conscience serve to consolidate a structure already formed.