I address an apparent conflict between Spinoza’s concepts of immanent causation and acting/doing [agere]. Spinoza apparently holds that an immanent cause undergoes [patitur] whatever it does. Yet according to his stated definition of acting and undergoing in the Ethics, this is impossible; to act is to be an adequate cause, while to undergo is to be merely a partial cause. Spinoza also seems committed to God’s being the adequate cause of all things, and, in a well-known passage, appears to deny (...) categorically that God is capable of undergoing. How then can God also be the immanent cause of all things, as Spinoza claims? On the basis of a close reading of the passage in question, I argue that Spinoza actually distinguishes between two senses of undergoing. An immanent cause undergoes not by being a partial cause but rather by being the metaphysical subject of its effect. While this sense of undergoing has its roots in scholasticism, Spinoza’s willingness to attribute such a capacity to undergo to God is idiosyncratic and reveals important ways in which his understanding of essence, perfection, and causation differs from the scholastic model. (shrink)