The radical nature of Deleuze’s materialism lies in its overturning of the central principle of dialectical materialism: organization. In dialectical materialism, the dynamism of matter comes from the activity or process of organization, the ordering of things through dialectical relations of mutual interdependence such that they become parts or members of a whole, where each part is an organ with its designated function within an integrated or systemic totality. The template of this kind of causality is the organism, a being that is able to spontaneously generate itself by virtue of its capacity for self-organization. This is why I suggested earlier that Marxism is an organismic vitalism. For Deleuze, however, matter as the plane of immanence is a dynamism of the differentiations , speeds, and flows of particles that are prior to any organized form. Following Hjelmslev, Deleuze and Guattari define matter as “the unformed, unorganized, nonstratified, or destratified body and all its flows: subatomic and submolecular particles, pure intensities , prevital and prephysical free singularities” (43). The truly material body is the body that subsists in the plane of immanence. It is not an organized system but “an aggregate whose elements vary according to its connections, its relations of movement and rest, the different individuated assemblages it enters” (256). Hence, the material body is not an organism but a body without organs.
Pheng Cheah, “Non-Dialectical Materialism,” in New Materialisms: Ontology, Agency, and Politics, ed. Diana Coole & Samantha Frost (via trashingdays)