This paper seeks to reconstruct philosopher Aleksandr Bogdanov’s approach to the philosophy of Spinoza in the context of the debate against Plekhanov. I demonstrate that the Soviet interest in Spinoza’s theory has never been purely historical, but rather, it served an important function in developing the theoretical foundations for Marxist philosophy. However, Bogdanov was one of only a very few who objected strongly to Plekhanov’s attempt to relate Spinoza’s philosophy to Marxism in a direct way. Two principles underlie Bogdanov’s critique: (...) one being methodological, the other—systematic. The methodological principle has a hermeneutical character, since it demands that we treat historical concepts by taking into account their context and their changes during the time. According to Bogdanov, failing to fulfil this principle results in the dogmatization and instrumentalization of philosophy, and transforms it into political doctrine. The systematic principle concerns Bogdanov’s radical rethinking of the relationship between extension and thought. I argue that by rethinking Spinoza’s concepts in the framework of “ideo-empirical parallelism”, Bogdanov develops his own theory of cognition, which he called “empiriomonism”. When considered in historical context, I argue that these debates can serve as a window into the foundational role the Spinoza’s philosophy has played in the formation of different versions of Russian Marxism, as well as in the development of Russian Marxism in general. (shrink)