Samuel Clarke was one of Spinoza's earliest and fiercest opponents in England. I uncover three related Clarkean arguments against Spinoza's metaphysic that deserve more attention from readers today. Collectively, these arguments draw out a tension at the very heart of Spinoza's rationalist system. From the conjunction of a necessary being who acts necessarily and the principle of sufficient reason, Clarke reasons that there could be none of the diversity we find in the universe. In doing so, Clarke potentially reveals an (...) inconsistent triad in Spinoza. Responses to this inconsistency map onto a deep division in the contemporary Spinoza literature. I conclude that Clarke's arguments provide a new approach to the recently revived debate over acosmic interpretations of Spinoza and point to new interpretive possibilities. (shrink)