 But arguably this is not how Spinoza understands the eternal part of the mind. The idea of the eternal essence of the body is just the “first thing [primum]” (cf. E2p11) that grounds my mind’s eternal existence: it is the foundation of eternal ideas of other things, just as the durational idea of this body as changing is the foundation of imaginative ideas of other things. “[T]he Mind is eternal, insofar as it conceives things under a species of eternity” (E5p31s). Since for Spinoza any human mind is essentially an idea of a certain “actually existing” body, cognition of that body is the foundation of all cognition whatsoever. This is true whether we are talking about imaginative cognition of the external bodies we bump up against in duration; or about intellectual cognition of eternally existing essences: “Whatever the mind understands under a species of eternity, it understands…from the fact that it conceives the body’s essence under a species of eternity” (E5p29). In short, for Spinoza all cognition of eternal truths rests on a cognition of our own body as an eternal essence. We can thus understand the idea of enlarging or maximizing the eternal “part” of our minds in terms of the number of eternal truths, intuitive and rational, that we can acquire in the course of our existence – or, as on innatist readings (see 3.1), the number of eternal truths that we can make into powerful “parts” of our minds.