From the abstract let us pass to the concrete. Recognizing men as the beings whose conduct is most evolved, let us ask under what conditions their conduct, in all three aspects of its evolution, reaches its limit. Clearly while the lives led are entirely predatory, as those of savages, the adjustments of acts to ends fall short of this highest form of conduct in every way. Individual life, ill carried on from hour to hour, is prematurely cut short; the fostering of offspring often fails, and is incomplete when it does not fail; and in so far as the ends of self-maintenance and race-maintenance are met, they are met by destruction of other beings of different kind or of like kind. In social groups formed by compounding and re-compounding primitive hordes, conduct remains imperfectly evolved in proportion as there continue antagonisms between the groups and antagonisms between members of the same group--two traits necessarily associated; since the nature which prompts international aggression prompts aggression of individuals on one another. Hence the limit of evolution can be reached by conduct only in permanently peaceful societies. That perfect adjustment of acts to ends in maintaining individual life and rearing new individuals, which is effected by each without hindering others from effecting like perfect adjustments, is, in its very definition, shown to constitute a kind of conduct that can be approached only as war decreases and dies out. A gap in this outline must now be filled up. There remains a further advance not yet even hinted. For beyond so behaving that each achieves his ends without preventing others from achieving their ends, the members of a society may give mutual help in the achievement of ends. And if, either indirectly by industrial co-operation, or directly by volunteered aid, fellow-citizens can make easier for one another the adjustments of acts to ends, then their conduct assumes a still higher phase of evolution; since whatever facilitates the making of adjustments by each, increases the totality of the adjustments made, and serves to render the lives of all more complete. § 7. The reader who recalls certain passages in _First Principles_, in the _Principles of Biology_, and in the _Principles of Psychology_, will perceive above a restatement, in another form, of generalizations set forth in those works. Especially will he be reminded of the proposition that Life is "the definite combination of heterogeneous changes, both simultaneous and successive, in correspondence with external co-existences and sequences;" and still more of that abridged and less specific formula, in which Life is said to be "the continuous adjustment of internal relations to external relations."