Spinoza claims we can control any passion by forming a more clear and distinct idea of it. The interpretive consensus is that Spinoza is either wrong or over-stating his view. I argue that Spinoza’s view is plausible and insightful. After breaking down Spinoza’s characterization of the relevant act, I consider four existing interpretations and conclude that each is unsatisfactory. I then consider a further problem for Spinoza: how his definitions of ‘action’ and ‘passion’ make room for passions becoming action. I (...) propose two solutions to this problem, both of which yield a hint regarding what act Spinoza has in mind. Using that hint, I propose that we can appreciate Spinoza’s insight by considering how philosophizing about a feeling can 'kill the mood.' The act of grasping how a passion exemplifies certain general truths, I hold, is a distinctly rational activity that has all the features Spinoza describes. I conclude by showing how this interpretation fits with Spinoza’s larger views on rational knowledge, rational joy, the comprehensibility of passions, and the relation between second- and first-order ideas. (shrink)