  The meaning of ‘perfection’ (perfectio) in various passages of the Ethics is obscured by the fact that Spinoza uses the term both in what he takes to be its common meaning and also in a narrow, formal sense. In some passages, such as IV Preface, Spinoza treats perfection, like good and evil, to be a label that people apply to things, to be explained in terms of those people’s use of the label: people call a thing perfect which conforms to the model of the thing that they create for themselves. In other passages, however, Spinoza treats perfection as whatever is “positive” or “real” in a thing, a genuine property, and this concept forms part of his formal apparatus (IId6).