The author analyzes the scientific value of key ideas forming the social and philosophical doctrine of Karl Marx. The author distinguishes three levels of scientific abstraction ‒ a philosophical one, considering social reality different from animate and inanimate nature; sociological, studying society as an organizational form of existence of this reality and typological, considering the types of social structure that exist in history. The author recognizes the scientific adequacy of the central philosophical and sociological ideas of Marx, in particular, the idea of the deterministic impact of the material factors of human activity, represented by human needs, on the consciousness of people; the idea of the domination of practice over the spiritual activity of people; the idea of the determining role of material production in relation to other forms of social practice; the idea of primacy of the economic structure over social, political and spiritual structures. These ideas remain valid (in case they are properly understood), which can not be said about the Marxian notions of the class structure and historical prospects of capitalism. Marx is interested in the substantial specificity of social reality associated with the presence of based on abstract-logical thinking consciousness and free will in a person. Free will is an ability to choose behavioral responses to the effects of the external and internal environment. This ability, which turns a person, in the words of Herder, into «the first freedman of nature», deprives human history of the correct repeatability of events, questions the preservation of the fundamental principles of determinism in history.