As the organs of inferior animals are moulded into fitness for the requirements of life, so, simultaneously, through nervous modifications, their sensations, instincts, emotions, and intellectual aptitudes are also moulded to these requirements,--in the gregarious animals to the conditions of gregarious life. Many evolutionists appear to regard the variability of man as ceasing with civilized life, but the whole analogy of nature is against such a theory; we must assume that man, like other animals, is moulded to suit his requirements, and that moral changes are among those thus wrought out. Aggressive actions often entail suffering on the individuals of a group performing them, as well as on the group as a whole, and on the other hand, harmonious cooeperation in a group profits the average of its members; so that there is a tendency to survival of groups having such adaptation of nature. And just as a love of property, formerly gratified by possession of food and shelter, came later to be extended to the weapons for obtaining these, and, later, even to the raw materials, the pleasure in ownership becoming more and more abstract and remote from material satisfaction, so the natural impatience of animal nature at restraint of its powers becomes in man a sentiment of egoistic justice, for justice requires the free play of all forces in order that the results of character may fall upon the individual. It is more difficult to understand how the altruistic sentiment of justice comes into being. On one hand, its implication is that it can be developed only by adaptation to social life; on the other, it appears that social life is impossible without the maintenance of those equitable relations which imply a sentiment of justice. These requirements are fulfilled by a pro-altruistic sentiment of justice, which takes its place. The first deterrent from aggression, among animals, is fear of retaliation; a further restraint, with man, is fear of reprobation or social disgrace. To these are to be added the feelings arising under political and religious authority--the dread of legal punishment and the dread of divine vengeance; and these four kinds of feelings cooeperate, forming a body of feeling, which checks the primitive tendency to pursue the objects of desire without regard to the interests of fellow-men, and though containing nothing of the altruistic sentiment of justice, makes social cooeperation possible. Creatures which become gregarious, tend to become sympathetic in degrees proportionate to their intelligence--by sympathy being meant the arousing of kindred feeling by the witness of a display of feeling in others, sympathy being fostered by common enjoyments and sufferings. The altruistic sentiment of justice is slow in assuming a high form, "partly because its primary component does not become highly developed until a late phase of progress, partly because it is relatively complex, and partly because it