Leibniz's principle of sufficient reason (PSR) is the claim that everything has a sufficient reason. But is Leibniz committed to the necessity or to the contingency of his great principle? I argue that Leibniz is committed to its contingency, given that he allows for the absolute possibility of entities that he claims violate the PSR. These are all cases of qualitatively indiscernible entities, such as indiscernible atoms, vacua, and bodies. However, Leibniz's commitment to the contingency of the PSR seems to stand in tension with his inference of the PSR from his theory of truth. I argue that this apparent tension can be resolved satisfactorily. When it comes to his modal views on the PSR, Leibniz's position is entirely consistent.

中文翻译：

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莱布尼茨充分理由原则的模态地位

莱布尼茨的充分理由原则 (PSR) 主张一切事物都有充分的理由。但是，莱布尼茨是致力于他伟大原则的必然性还是偶然性？我认为莱布尼茨致力于其偶然性，因为他允许他声称违反 PSR 的实体的绝对可能性。这些都是质量上难以分辨的实体的例子，例如难以分辨的原子、真空和物体。然而，莱布尼茨对 PSR 偶然性的承诺似乎与他从真理论中对 PSR 的推断相矛盾。我认为这种明显的紧张局势可以得到令人满意的解决。谈到他对 PSR 的模态观点，莱布尼茨的立场是完全一致的。