But the main sociological movement has issued from other origins than those of Comte and Spencer. The master idea, which animated alike the initiator of sociology and his chief continuator, was that of evolution. The evolutionary concept of an orderly development proceeding by discoverable "laws" was applied by Comte to the past, present and future of Western civilization, itself taken as the essential feature of man's activity. Spencer extended this evolutionary concept to other types of society than that of Western civilization; aiming indeed in his "De scriptive Sociology" (of which the volumes continue to be com piled and published under the terms of his testamentary dispo sitions) at a comprehensive account of every social type to be found on the earth.
Independently of the writings of both Comte and Spencer, there proceeded during the i9th century, under the influence of the evolutionary concept, a thoroughgoing transformation of older studies like History, Law and Political Economy; and the creation of new ones like An thropology, Social Psychology, Comparative Religion, Crimi nology, Social Geography. It is from these sources that have sprung the main body of writing, investigation, research, that to-day can properly be called sociological. To give content to this statement some illustrative cases may be examined. Take, to begin with, the transformation of Law and History from rela tively isolated studies of discursive or narrative type into some thing ever approximating to social sciences of an evolutionary kind. Discoveries relating to the history of the family con tributed largely to the renewal of juristic studies on an evolu tionary basis. Disputable as the theories of Bachhofen, Morgan, MacLennan, etc., were in many respects, they proved by evidence the existence of forms of the "family," very different from those known up to that time, and also their generality. The remarkable identity of the nomenclature of parentage in Australia, and among the redskins of North America, was significant. The similarities between the Iroquois tribes and the Romance na tions, if exaggerated by Morgan, were not purely fictitious. Re semblances of the same kind were proved in the case of criminal law and the law of property, and thus a school of comparative law was founded, whose object was to bring out these agree ments, to classify them systematically, and endeavour to ex plain them as evolutionary phenomena. Of this school of ethno graphic jurisprudence Herman Post may be regarded as founder, and other names such as those of Kohler, Bernhoeft, and Stein metz are to be associated with his.
Simultaneously with the foregoing changes, the concept of Institutions as social phenomena exerted a profound influence upon modes of study in both History and Law. It was observed that Institutions during their evolution preserve their essential characteristics throughout long periods of time, and even on occasion through all the series of a continuous collective exist ence; for they express the more constitutional elements in every social organization. Stripped of the covering of particular facts which conceals their internal structure and function, institutions, it could be asserted, while varying more or less from one country to another, presented striking similarities in different societies.
Rapprochements thus became possible, and comparative history came into prominence. The Germanists and the German Roman ists, Maurer, Wilda and Ihering, established resemblances be tween the laws of the various Germanic peoples, and between those of the Germans and Romans. By comparison of the classical texts relating to the organization of Greek and Roman cities, Fustel de Coulanges managed to portray in its essential particulars the abstract type of the city. With Sumner Maine, the field of comparison, still further widened, embracing besides Greece and Italy, India, Ireland, the Slav nations.
Nothing better testifies to the impor tance of the scientific transformations in the whole field of social studies than the evolution which political economy under went during the 19th century. Under the influence of different ideas, otherwise ill-defined, but which it is, however, possible to refer to two principal types, it lost, first in Germany something of that merely dialectical character which made it possible for Comte to contrast it with sociology as the type of the "idealogic" method of construction. To establish the legitimacy of Protection, and more generally of the economic action of the State, List re acted against both the individualism and the cosmopolitanism of the Liberal school. The "National System of Political Economy" maintains the principle that intermediate between humanity and the individual is the nation, with its language, literature, insti tutions, manners and past. The classical economist fashioned an economic world having no visible existence—the Giiterwelt—an isolated world uniform throughout—in which the conflict of in dividual forces acted according to inflexible economic laws. As a matter of fact, it is observable that individuals make their efforts to grow rich in collectivities widely different from one another; and the nature of these efforts changes, and their success varies with the characteristics of the collectivity in which they are dis played. A practical consequence of this principle is that the State acts on the economic conduct of individuals by means of the "re forms" which it introduces, and by its external policy. A theoreti cal consequence is that economic "laws" are seen to vary from one nation to another, and it becomes increasingly manifest that a "National Economy" based on observation, should take the place of the abstract, a priori economics. True, the conception of a "nation" is an obscure idea ; and the very definition of national economy would appear to negate the possibility of truly scien tific laws, since it conceives its object as unique and excludes com parison. List made, nevertheless, an important step in advance by introducing into economic speculation the idea that a given society has a real existence, and that the economic and other mani festations of its own life are in reciprocal relations.