Dialectical and Formal Logic

Dialectical logic (or dialectics) is the logic of concepts,whereas formal logic is propositional logic.


Although dialectics dates back to the ancients, it was only with Hegel that dialectical logic was given a systematic exposition.

Formal logic considers the relation between the truth-value of propositions of the type x ∈ S (“x is an element of the set S”). Concepts are regarded as sets of discrete elements, that is, reduced to their extension and the validity of deductions is resolved by comparison of the elements of the relevant sets.

Dialectical logic, on the contrary, is concerned with the truth of positions of the form “c is absolute” (or “everything is c”). Thus, dialectics examines the limits of a concept, and the conditions under which it falls into contradiction with itself. The concepts which Dialectics deals with are true, concrete concepts, that is, concepts which embody the wisdom of human history and culture in them, not formal concepts.

Vygotsky acquired his knowledge of dialectics from a reading of Marx, Engels and Lenin, and he makes frequent reference to its importance for his thinking. For example:

“Dialectical thinking does not place logical and historical methods for acquiring knowledge in opposition to one another. In accordance with Engels’s well known definition, the logical method of investigation is itself an historical method. Logical methods are merely freed from their historical form and from the element of chance in history that interferes with the structure of the scientific account. The logical course of thought and history begin with the same thing. Moreover, the development of logical thought is nothing but a reflection of the historical process in an abstracted and theoretically consistent form. It is a refined reflection of the historical process, but it is refined in correspondence with the laws that historical reality itself teaches us. The logical mode of investigation provides the possibility for studying any aspect of development in it most mature stage and in its classic form.” (LSVCW, v. 1, p. 47)

References Ilyenkov, E. (1960). Dialectics of the Abstract & the Concrete in Marx’s Capital, http://www.marxists.org/archive/ilyenkov/works/abstract/index.htm

Ilyenkov, E. (1974). Dialectical Logic, http://www.marxists.org/archive/ilyenkov/works/essays/index.htm

-- AndyBlunden - 15 Nov 2013


Topic revision: r9 - 20 Nov 2013, AndyBlunden

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