Must we not recognize also a third postulate, namely, that men must be able to assume that others, who keep things or maintain conditions or employ agencies that are likely to get out of hand or escape and do damage, will restrain them or keep them within proper bounds? Just as we may not go effectively about our several businesses in a society dependent on a minute division of labor if we must constantly be on guard against the aggressions or the want of forethought of our neighbor, so our complex social order based on division of labor may not function effectively if each of us must stay his activities through fear of the breaking loose or getting out of hand of something which his neighbor harbors or maintains. There is danger to the general security not only in what men do and the way in which they do it, but also in what they fail to do in not restraining things they maintain or agencies they employ which may do injury if not kept strictly in hand. The general security is threatened by wilful aggression, by affirmative action without due regard for others in the mode of conducting it, and by harboring and maintaining things and employing agencies likely to escape or to go out of bounds and do damage. Looked at in this way, the ultimate basis of delictal liability is the social interest in the general security. This interest is threatened or infringed in three ways: (1) Intentional aggression, (2) negligent action, (3) failure to restrain potentially dangerous things which one maintains or potentially dangerous agencies which one employs. Accordingly these three are the immediate bases of delictal liability.