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. (shrink)

The Principle of Sufficient Reason is a powerful and controversial philosophical principle stipulating that everything must have a reason or cause. This simple demand for thoroughgoing intelligibility yields some of the boldest and most challenging theses in the history of metaphysics and epistemology. In this entry we begin with explaining the Principle, and then turn to the history of the debates around it. A section on recent discussions of the Principle will be added in the near future.