As has just been suggested, Spencer also applies these principles to explain the laws of social structure and function and to describe the evolution of society, and his in inter est in all these considerations lies n his attempt ing to make clear the unity of the evolutionary processes, whether organic or inorganic.
The application of the evolutionary formula to the study of psychology has already been in general indicated. Mental functions grow in a way that is precisely parallel to the growth of certain organic structures and functions. Con sequently integration, differentiation and segre gation can he traced in mental life as well as in organic life. And in so far as the conditions of mental life are knowable at all, these con ditions have to be defined in the terms of the same evolutionary formula which apply to plas tic bodies in general, that is, to their structure and to their functions. In order to apply these considerations to that study of ethical problems which so early interested him and to the de fense of those social doctrines which he so early emphasized, Spencer laid especial stress -upon naturalism in ethics, that is, upon the necessity of consulting the natural conditions of organic life in order to define the norms of conduct. Conduct is an evolutionary phenom enon and is to be considered in the light of the general formula for evolution. Conduct, for instance, is a part of the adjustment of the organism to its environment and is to be judged in the light of the laws of that adjust ment. That conduct which secures the most perfect adjustment is at once the most accept able to society, and, by virtue of the conditions under which mind has developed, is in the long run most satisfactory to the individual con cerned. For in case of the human organism, the adjustment of internal to external con ditions normally occurs in society. Hence such adjustment as keeps the individual in harmony with his social order is conduct of the type favored by evolution. The inherited effects of experience appear in those of our instincts which fit us for harmonious social life. On the other hand, social harmony does not mean social subordination. The goal of social de velopment is a condition of equilibrium in which the individual is as little interfered with by his society as possible, in so far, namely, as interference would involve coercion or re straint. Meanwhile, as this goal is approached, the individual grows increasingly differentiated in his social functions, better adapted to a wider and wider range of social conditions and more definite in his functions.
Notable in Spencer's work has been his at titude toward the problems of past and of con temporaneous religions. The religions of the world are the results of evolutionary processes whose knowable aspect Spencer elaborately dis cusses in his
In his 'Essays on Education' Spencer has made prominent the importance of the study of natural science and has emphasized the sig nificance of the sort of training- which he him self originally received from his father.
In sum, Spencer was one of the leaders of the age in which the modern doctrine of evolu tion came into prominence. In his own devel opment he was, until 1860, when he first be came, acquainted with Darwin, substantially independent of other evolutionary thinkers, at least among his contemporaries. Indirectly and somewhat unconsciously, he was influ enced (as Prof. John Dewey has pointed out) by the tradition of 18th century French philosophy; consciously he was molded by the English liberalism of his time; and less promi nently he was affected by the Kantian epis temoloky, with its limitation of human knowl edge to the phenomenal world. The Kantian influence was indirect, occurring through Spencer's reading of Hamilton and of Mansel. Spencer's popular influence has been very large — still larger in America than in England. His most notable undertaking is the effort to formulate the doctrine of evolution in gen eral terms; as a part of the .undertaking, his work in psychology, in sociology and, to a less degree, in educational theory and in ethics, has proved widely influential. Consult Elliott, H.,