Engels co-developed historical materialism with Marx and, after Marx's death, systematized their joint theory into "dialectical materialism" in works such as "Anti-Dühring" (1878), presenting it as a general science of nature, history, and thought. His own "The Condition of the Working Class in England" (1845) supplied empirical grounding for their theory of class, and "The Origin of the Family, Private Property and the State" (1884) extended historical materialism to explain the emergence of monogamy, property, and the state through women's subjugation.
Intellectual setting
Engels co-wrote "The German Ideology" and "The Communist Manifesto" with Marx and financially supported him for decades from his income managing the family firm in Manchester; after Marx's death in 1883 he edited and completed the second and third volumes of "Capital" from Marx's manuscripts.
Key ideas
Dialectical materialism
Engels systematized Marx's method into a general dialectical account of nature, history, and thought as governed by objective laws of development through contradiction, a formulation that became the basis for later orthodox Marxist philosophy of science.
The origin of the family and women's subjugation
Engels argued that the monogamous family, private property, and the state emerged together historically, and that women's subordinate status originated in this transition rather than in nature, an argument that became foundational for later Marxist feminism.
Legacy
Engels's systematization of dialectical materialism shaped Soviet and international Marxist orthodoxy well into the twentieth century, and "The Origin of the Family" remains a foundational text for Marxist and socialist-feminist theories of gender and property.