This paper asks: Is the quantifier variantist committed to metaphysical vagueness? My investigation of this question goes via a study of vague existence. I’ll argue that the quantifier variantist is committed to vague existence and that the vague existence posited by the variantist requires a puzzling sort of metaphysical vagueness. Specifically, I distinguish between (what I call) positive and negative metaphysical vagueness. Positive metaphysical vagueness is (roughly) the claim that there is vagueness in the world; negative metaphysical vagueness is (roughly) the claim that there is vagueness that is not in our language or thought. I’ll argue that the quantifier variantist’s commitment to vague existence comes with positive metaphysical vagueness—even if it doesn't require negative metaphysical vagueness.

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.