Marxist philosophy or Marxist theory are works in philosophy that are strongly influenced by Karl Marx's materialist approach to theory, or works written by Marxists. Marxist philosophy may be broadly divided into Western Marxism, which drew from various sources, and the official philosophy in the Soviet Union, which enforced a rigid reading of Marx called dialectical materialism, in particular during the 1930s. Marxist philosophy is not a strictly defined sub-field of philosophy, because the diverse influence of Marxist theory has extended into fields as varied as aesthetics, ethics, ontology, epistemology, social philosophy, political philosophy, the philosophy of science, and the philosophy of history. The key characteristics of Marxism in philosophy are its materialism and its commitment to political practice as the end goal of all thought.
The theory is also about the struggles of the proletariat and their reprimand of the bourgeoisie.
Marxist theorist Louis Althusser, for example, defined the philosophy as "class struggle in theory", thus radically separating himself from those who claimed philosophers could adopt a "God's eye view" as a purely neutral judge.
The philosopher Étienne Balibar wrote in 1996 that "there is no Marxist philosophy and there never will be; on the other hand, Marx is more important for philosophy than ever before." So even the existence of Marxist philosophy is debatable (the answer depends on what is meant by "philosophy"). Balibar's remark is intended to explain the significance of the final line of Karl Marx's 11 Theses on Feuerbach (1845), which can be read as an epitaph for philosophy: "The philosophers have only interpreted the world, in various ways; the point is to change it".
If this claim (which Marx originally intended as a criticism of German Idealism and the more moderate Young Hegelians) is still more or less the case in the 21st century, as many Marxists would claim, then Marxist theory is in fact the practical continuation of the philosophical tradition, while much of philosophy is still politically irrelevant.