There are thus seen to be at least three distinct reasons why our native endowment of capacities and desires needs control and direction. In the life of the individual, instinctive desires must be adjusted to one another in order that their harmonious fulfillment may be made possible. The desires and native reactions of individuals must be checked and modified if individuals are to live successfully and amiably in group association, in which they must, in any case, live. And, finally, so vastly complicated have become the physical and the social machinery of civilized life that it is literally impossible to depend on instincts to adjust us to an environment far different from that to which they were in the process of evolution adapted. In the light of these conditions men have found that if they are to live happily and fruitfully together, certain original tendencies must be stimulated and developed, others weakened, redirected, and modified, and still others, within limits possibly, altogether repressed. Individuals display at once curiosity and fear, pity and pugnacity, acquisitiveness and sympathy. Some of these it has been found useful to allow free play; others, even if moderately indulged, may bring injury to the individual and the group in which his own life is involved. Education, public opinion, and law are more or less deliberate methods society has provided for the stimulation and repression of specific instinctive tendencies. Curiosity and sympathy are valued and encouraged because they contribute, respectively, to science and to cooeperation; pugnacity and acquisitiveness must be kept in check if people are not simply to live, but to live together happily. But the substitution of control for caprice in the living-out of our native possibilities is as difficult as it is imperative. As already noted, instincts are imperious driving forces as well as mechanisms. While we can modify and redirect our native tendencies of fear, curiosity, pugnacity, and the like, they remain as strong currents of human behavior. They can be turned into new channels; they cannot simply be blocked. Indeed, in some cases, it is clearly the social environment that needs to be modified rather than human behavior. Though it be juvenile delinquency for a boy to play baseball on a crowded street, it is not because there is intrinsically anything unwholesome or harmful in play. What is clearly demanded is not a crushing of the play instinct, but better facilities for its expression. A boy's native sociability and gift for leadership may make him, for want of a better opportunity, a gangster. But to cut off those impulses altogether would be to cut off the sources of good citizenship. The settlement clubs or the Boy Scout organizations in our large cities are instances of what may be accomplished in the way of providing a social environment in which native desires can be freely and fruitfully fulfilled.