Marcuse considered theory the highest form of praxis

Evidence

For Marcuse, both action' and the taking into account of today and its situation’ were vague, indistinct ideas, and he himself was not politically active in any sense. He considered theory the highest form of praxis, and in the early 1930s was working on research into Hegel’s Ontology and the Foundation of a Theory of Historicity, with which he hoped to take his Habilitation with Heidegger. — Rolf Wiggershaus, The Frankfurt School, 419