Social conditions can thus be modified so as to give satisfaction to a larger proportion of natural desires. On the other hand, civilization in the twentieth century remains so divergent from the mode of life to which man's inborn nature adapts him that the thwarting of instincts becomes inevitable. Impulses, in the first place, arise capriciously, and one of the conditions of our highly organized life is regularity and canalization of action. Our businesses and professions cannot be conducted on the spontaneous promptings of instinct. The engineer, the factory worker, the business man, cannot allow themselves to follow out whatever casual desire occurs to them whenever it occurs. Stability and regularity of procedure, demanded in most professions, are incompatible with random impulsive behavior. To facilitate the effectiveness of certain industries, for example, it may be necessary to check impulses that commonly receive adequate satisfaction. Thus it may be essential to enforce silence, as in the case of telephone operators or motormen, simply because of the demands of the industry, not because there is anything intrinsically deserving of repression in the impulse to talk. Again, the mere fact that a man lives in a group subjects him to a thousand restraints and restrictions of public opinion and law. A child may come to restrain his curiosity when he finds it condemned as inquisitiveness. We cannot, when we will, vent our pugnacity on those who have provoked it; we cannot be ruthlessly self-assertive in a group; or gratify our native acquisitiveness by appropriating anything and everything within our reach.