Bogdanov is a major rival to the philosophical orthodoxy of Plekhanov and Lenin. We explicate the foundational notions of his philosophy—praxis and experience—and trace his revisionism to Kant, Fichte, Mach, and Spencer. We show that Bogdanov's approach represents a predominantly pragmatic reading of Marx, influenced by the empiricism of Mach and Spencer as well as by Kantian apriorism. Bogdanov's version of Unified Science—Tektology—is considered against his philosophical background. The concept of praxis is at the center of the controversy between Marxist (...) orthodoxy and revisionism. We analyze the connection between Bogdanov's philosophy of praxis, and the constructivism of the young Marx. Consequently, we see how Bogdanov's quest for infinite creativity is conceptually connected with the Fichtean–Marxian quest for infinite growth. Furthermore, we consider the issue of technological growth in a framework of the contemporary limits to growth debate. (shrink)