Marx often called his materialism a ‘practical materialism,’ by which he meant that matter enters into human life as the support and body of praxis. Matter plain and simple, exterior to man and in terms of which his behavior could be explained, is simply not at issue. Marx’s materialism is the idea that all the ideological formations of a given society are synonymous with or complementary to a certain type of praxis, i.e., the way this society has set up its basic relationship with nature. It is the idea that economy and ideology have interior ties within the totality of history, like matter and form in a work of art of a perceptual thing. The meaning of a picture or a poem cannot be separated from the materiality of the colors or the words; it is neither created nor understood from the idea out. A perceptual thing can be understood only after it has been seen, and no analysis or verbal report can take the place of this seeing. Likewise, the ‘spirit’ of a society is already implied in its method of production because this latter is already a particular way in which men – whose scientific, philosophical, and religious concepts are either the simple development or the imaginary counterpart of that method – co-exist.
Maurice Merleau-Ponty, Sense and Nonsense