"If Marx had not thrown together interaction and work under the label of social practice (Praxis), and had he instead related the materialist concept of synthesis likewise to the accomplishments of instrumental action and the nexuses of communicative action, then the idea of a science of man would not have been obscured by identification with natural science. Rather, this idea would have taken up Hegel's critique of the subjectivism of Kant's epistemology and surpassed it materialistically. It would have made clear that ultimately a radical critique of knowledge can be carried out only in the form of a reconstruction of the history of the species, and that conversely social theory, from the viewpoint of the self-constitution of the species in the medium of social labour and class struggle, is possible only as the self-reflection of the knowing subject."

Haberdon, knowledge as social T as below, on where/how Marxdon went wrong ;-)