Conatus
Conatus is the striving of every thing to persist in its being — the fundamental drive that underlies desire, emotion, and action.
In depth
Every mode of substance strives to continue existing. This striving (conatus) is not a conscious choice but a fundamental feature of being a finite thing. In humans, conatus manifests as desire — the drive to maintain and enhance our power of acting. Conatus is the foundation of Spinoza's psychology: all emotions are variations of this basic striving being aided or hindered.
Why it matters
Conatus replaces the idea of "will" as a mysterious mental faculty. Your desires and motivations are not random or sinful — they are expressions of your nature as a being that strives to persist and flourish. Understanding this is the basis for understanding all emotions.
Source references
- Ethics III.P6-P7