The article is devoted to the problem of the unity of Slavs in the works of the Russian thinkers of Slavophile and conservative directions of the Russian philosophical thought. Slavophiles, as shown in the article, despite the name given to them, did not consider the unity of the Slavs as the defining idea of their art, but it was their ideas that initiated the development of the concept of types of cultures elaborated by N. I. Danilevsky, who made an attempt to approach the problem of the unity of the Slavs from a scientific point of view. We present Danilevsky’s views on the possibility and necessity of political unification of the Slavs as a condition for the formation of the Slavic type of culture. The idea of forming a Slavic type of culture gained its supporters and critics. The most significant arguments against the possibility of formation of the Slavic type of culture were presented in a number of articles by the conservative thinker K. N. Leontief. He believed that cultural unity is impossible due to the fact that the Slavic peoples do not fit into the cultural Byzantine code of Russia, and political unity, although possible, is undesirable, because it will have the devastating consequences for the Russian state. We present in a systematic way Leontief ’s arguments given him in different articles. The authors substantiate the historical correctness of K. N. Leontief in his conclusions about the ephemerality of the Slavic idea.