The purpose of the article is the research of the unpublished methodological scientific work of the Russian historian Nikolay Kareev, called the The General Methodology of the Humanities. This book was written in 1922, but was not published due to censorial restrictions. The text solved different problems of the humanities from the point of view of positivism. In an historiographical aspect, it has some continuity with the course “The Methodology of the History” by Alexander Lappo-Danilevsky, who taught it at the University of Petrograd (after the death of Lappo-Danilevsky in 1919, it was planned to pass this course to Kareev). However, the General Methodology is an original course, written from the different standpoints of Lappo-Danilevsky. This article consists of the introduction and a published fragment from the General Methodology. This fragment includes the second chapter, which is called “The Logical Prerequisites of the Methodology”. Here, Kareev characterized logic as a condition of any methodology, and considered existing methods of cognition, such as inductive, deductive, comparative, and historical; he talked about scientific laws and their classification; he dwelled on the types of inferences and syllogisms in detail, as well as on common mistakes. In this chapter, Kareev not only dealt 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). We reconstructed the text of these paragraphs according to a monograph by Kareev, which is held in the Research Department of Manuscripts of the Russian State Library.