Spinoza's PSR as a Principle of Clear and Distinct Representation

It is argued first, that Spinoza's Principleof Sufficient Reason(PSR) is best seen as an auxiliary premise and not as an axiom of the Ethics; second, that Spinoza held the PSR to be a self-evidenttruth that indicates a necessary condition for clearly and distinctly representing the existence or non-existence of a thing; and third, that this interpretation of Spinoza's PSR explains the near absence of the PSR within the demonstrations of the Ethics as well as the importance of the principle in Spinoza's thought.