The purpose of this paper is the analysis of the methodological foundations of the historical and legal research of the famous historian and methodologist of law F. Taranovskyi and evolution of scientific views of the scientist from dogmatic of law to advocate of multiform nature of the state and law. This is confirmed by examination of law as a social phenomenon, which depends on passing in society processes, dialectical and systematic study of law, its well-defined methodology. That positivist methodology, according to scientists, could unleash the full advantages of the comparative method, using it to study the problems of science and social nature, adopting the position of a single methodology. Non-random changes in the conditions of observation of social phenomena is replaced by the fact that the same phenomenon occurs in a number of human communities under different conditions. Enough to compare to the same phenomenon in a particular variety of conditions, objectively present in different human societies, and in a variety of conditions can provide the true cause of the phenomenon as well, as is done in an arbitrary change of the conditions of the researcher.