Spinoza’s Ethics makes reference to three kinds of knowledge that humans are capable of winning: imagination, reason and intuitive knowledge of God. Of these, imagination is necessarily inadequate while the latter two are necessarily adequate. In other words, we remain passive in the first type of knowledge, but come into our power of acting in the latter two. The passage from the first to the second and third types of knowledge, however, remains, in Spinoza’s text, rather obscure. This paper seeks (...) to come to terms with how exactly the passage from passion to action is made in the Ethics while locating this particular problematic as a site at which various interpretations of Spinoza diverge with considerable stakes. I thus focus on Gilles Deleuze’s proposed answer to this problem as well as Pierre Macherey’s critique of Deleuze’s reading. I argue that the disagreement between Macherey and Deleuze is not merely interpretive, but rather indicates some of the stakes involved in assessing Spinoza’s theory of the passions and the imagination. An ‘optimistic’ appraisal of these features might lead one to Deleuze’s affirmationist project, while Macherey’s pessimism concerning the two might take a Spinozist politics in quite the opposite direction. I appreciate and assess multiple aspects of Macherey’s critique while nonetheless arguing that they do not prove damning for Deleuze’s affirmationist picture. I conclude with an analysis of vacillation of mind in Deleuze’s Spinoza, and place Deleuze’s thoughts on this note in conversation with his earlier reading of Nietzsche. (shrink)