Spinoza employs the term utilitas, familiar from Epicurean and Stoic thinkers (e.g., Cicero), to redefine the language of “good” and “evil” as referring to what is truly known to be useful or advantageous for human beings (E4def1–2). In Ethics 3, Spinoza explains moral language in terms of human desire: whatever we desire, we call “good” and whatever repels us, we call bad or “evil” (E3p9s, E3p39s). In Ethics 4, in the course of explaining how reason and its affects enable us to ameliorate our bondage to the passions, Spinoza introduces utile and utilitas to differentiate rational from merely imaginative ideas of good and evil. In the TTP and TP, invocations of utilitas generally denote rational ideas of the beneficial. In a crucial passage in TTP16, Spinoza attributes the force of contracts to perceived utilitas, noting that not all judgments of what is good are rational (iii/191–92). Spinoza also occasionally employs utilitas in epistemological and scientific contexts to denote what promotes the development of reason and understanding (e.g., Ep6, Ep36, E1p40s1); likewise, TTP7 refers to Spinoza’s own method of biblical hermeneutics as “useful” (iii/104).