The doctrine of striving (conatus) as our “actual essence” forms the metaphysical basis for Spinoza’s ethical project. Near the start of the third part of the Ethics, Spinoza articulates the doctrine: “Each thing, insofar as it is in itself, strives to persevere in its being [in suo esse perseverare conatur]” (E3p6, alt. trans.). The view that animate things naturally strive to preserve themselves had for centuries been part and parcel of Western philosophy, in particular through the teachings of Stoics, for whom the impulse (hormê) to self-preservation forms the basis of a naturalistic ethics. Still, the intellectual landscape had altered by Spinoza’s time in a radical way under the influence of the new mechanical sciences, undermining the teleological understanding of the way in which the world and things in it were ordered. In brief, naturalistic ethics had to be rethought given that it could no longer accommodate the traditional idea of ends.