Abstract
Naturalism pervades Spinoza’s doctrines of The Ethics, but the contours of it often bewilder us. In this light, I consider the account of falsity, or having a false idea, as presented by Spinoza in Proposition thirty_five of the Second Part, its demonstration, and the subsequent note. Based on my interpretation I argue for the claim that his account has coherence and makes sense. Further, I examine the significance of what Spinoza says about falsity for comprehension of his philosophy overall, especially as regards its contrasts with the philosophy of Descartes