Will, Body, Essence

At III, vii, Spinoza defines 'essence' as a thing's "endeavor to persist in its own being", a definition which, in his note to II, ix, he indicates applies to Mind, and to the Mind-Body conjunction. Hence, he implies that the definition does not apply to Body, i. e. he implies that the essence of Body is not its endeavor to persist in its own being. Instead, at V, xxii, he suggests that the essence of Body is, more precisely, the essence of "this or that body", which implies that the essence of Body consists in its individuality. That implication is reinforced by his general thesis that Modes are distinguished by corporeal differences, i. e. that adequate ideas are common to different modes, while inadequate ones are contingent on physical differences. However, he stops short of explicitly defining the 'essence of this or that Body' as a 'principle of Individuation', a principle which, as has been previously discussed here, entails Will, the principle of Differentiation in personal experience. On that definition, personal identity is a product of self-cultivation, not an eternal essence that both precedes and survives the existence of its associated body, as it is for Spinoza, in apparent contradiction to his Thought-Extension Parallelism.