An essentialist theory of modality claims that the source of possibility and necessity lies in essence, where essence is (obviously) then not to be defined in terms of necessity. Hence such theories owe us an account of why it is that the essences of things give rise to necessities in the way required. A new approach to understanding essence in terms of the notion of generalized identity promises to answer this challenge by appeal to the necessity of identity. I explore the prospects for this approach, and argue that it fails. If one favours an account of essence in terms of generalized identity, then one will not, I argue, be able to satisfactorily defend an essentialist theory of modality against the challenge; if one wishes to defend an essentialist theory of modality, and thereby to give an explanation of how necessity arises from essence, one should not understand essence in terms of generalized identity.

中文翻译：

---

通过身份从本质到必要性

一种本质主义的情态理论声称，可能性和必然性的根源在于本质，而本质（显然）则不是根据必然性来定义的。因此，这些理论欠我们一个解释，为什么事物的本质会以所需的方式产生必然性。根据广义同一性概念来理解本质的新方法有望通过诉诸同一性的必要性来回答这一挑战。我探索了这种方法的前景，并认为它失败了。如果人们倾向于从广义同一性的角度对本质进行解释，那么我认为，人们将无法令人满意地捍卫一种本质主义的模态理论以应对挑战；如果人们希望捍卫一种本质主义的模态理论，从而解释必然性如何从本质中产生，