  This epistemological ideal forms the core of Spinoza’s rationalistic ethics—and, hence, on one plausible account, the core of his Ethics. Spinoza’s monism entails that the sort of individuals that Aristotle regarded as primary substances are distinguished not by their own substantial unity, but by their conatus—their striving to persist. Thus, self-preservation is not just one possible goal of ethical agents; it is the very thing that makes those agents individuals. Our essence, and our ethical task, is thus to be active, whereas, by contrast, to be passive threatens our persistence. The mind persists through activity and is threatened by passivity. It is therefore in our self-interest to pursue adequate ideas through knowledge of the second and third kinds. The more we join our minds with God through adequate knowledge of things under the form of eternity, the less we are affected by external things and, hence, by our own passions, which are nothing but our passivity in the face of forces external to us. Adequate knowledge of God gives us equanimity and calm, and literally ensures our persistence. Ethical virtue is thus fundamentally epistemological. For Spinoza, the most rationalist of figures discussed here, the good life is the utterly rational life.