Abstract
This paper offers a defense of a much-maligned Leibnizian argument for the Principle of Sufficient Reason, the principle according to which whatever is has a sufficient reason or explanation. While Leibniz’s argument is widely thought to rely on a question-begging premise, the paper offers a wholly original and non-question-begging defense of that premise, a defense that Leibniz did not anticipate. The paper does not present this defense of Leibniz's argument as an interpretation of Leibniz; rather, the paper—more modestly in one way, less modestly in another—simply claims that this argument succeeds.