The focus of the article is the research of the unpublished methodological scientific work by the Russian historian Nikolay Kareev, which is called The General Methodology of the Humanities. This book was written in 1922, but was not immediately published due to censorship restrictions. In it, Kareev described the sphere of humanitarian knowledge, and presented the existence of a holistic research field as a problem of the humanities and describes the principles of its interrelationships. As well, he put the need to develop a common methodology for scientific research as a research task, and substantiated the position and methodological tools of history in the humanities. Тhe publication fragment from the General Methodology includes the second chapter, which is called “The Logical Prerequisites of the Methodology”. In this chapter, Kareev characterized logic as a condition of any methodology, considered existing methods of cognition, those being inductive, deductive, comparative, and historical, talked about scientific laws and its classification, and dwelled on the types of inferences and syllogisms in detail, as well as on common mistakes. In this chapter, Kareev dealt not only with the foundations of logic, but also with the theory of argumentation and the theory of proofs. He formulated the signs of scientific knowledge, those of verifiability, systematic, and completeness (integrity). The text solved the different problems of humanities from the point of view of positivism with some elements of neo-Kantianism.