More clearly in the case of human beings than in that of other animals is it shown that gregariousness establishes itself because it profits the variety. Where a variety live on wild food, they associate only in small groups; game and fruit, widely distributed, can support these only. "But greater gregariousness arises where agriculture makes possible the support of a large number on a small area; and where the accompanying development of industries introduces many and various cooeperations." The advantages of cooeperation can be had only by conformity to the conditions which association imposes--by such limitation of the pursuits of individuals as to leave a surplus of advantage to associated life. "This truth is illustrated by the unprosperous or decaying state of communities in which the trespasses of individuals on one another are so numerous and great as generally to prevent them from severally receiving the normal results of their labors." Mutual restraint being more imperative with human beings than with animals, there is with them a still more marked habit of punishment. "Through all which sets of facts is manifested the truth, recognized practically if not theoretically, that each individual, carrying on the actions which subserve his life, and not prevented from receiving their normal results, good and bad, shall carry on these actions under such restraints as are imposed by the carrying on of kindred actions by other individuals, who have similarly to receive such normal results, good and bad. And vaguely, if not definitely, this is seen to constitute what is called justice." In the highest gregarious creature, the necessity which we found, of an occasional sacrifice of the individual in defence of species, assumes large proportions, the defence being not only against enemies of other kinds, but also against enemies of the same kind. This obligation is less than that of care for offspring, or mutual restraint. It exists only as necessary to protect the society against destruction, hence only for defensive, not for offensive, war. It may be objected that war peoples the earth with the stronger, but this is not necessarily so, since the conquered may merely be fewer in number. And further, it is only during the earlier stages of human progress that the development of strength, courage, and cunning are of chief importance. But for an accident, Persia would have conquered Greece; and Tartar hordes once very nearly overwhelmed European civilization. The races best fitted for social life do not necessarily conquer, and there are injurious moral reactions on both conquering and conquered. Only defensive war retains a quasi-ethical justification. It belongs, however, to a transitional state, and is not justified by Absolute Ethics.