Aristotelian essentialism in David Lewis’s theory

David Lewis is usually thought to reject what Quine called ‘Aristotelian essentialism’. In this paper, I will define Aristotelian essentialism and locate it in the context of the criticism that Quine made of quantified modal logic. Indeed, according to Quine, Aristotelian essentialism would be one of the consequences of accepting quantified modal logic. Then, I will explain Lewis’s stance in the Quinean debate against quantified modal logic. Finally, I will deal with the question as to whether Lewis accepts or rejects Aristotelian essentialism. I think there are different plausible interpretations of the essentialist thesis, and I will distinguish between three such interpretations. This distinction between different interpretations of essentialism is both interesting per se and helpful in understanding the senses in which Lewis is or is not an antiessentialist. I will say, in fact, that while it is true that Lewis rejects Aristotelian essentialism under the first two understandings of the essentialist thesis, he endorses such a thesis according to a third understanding. I will then take this to show that there is a sense in which Aristotelian essentialism survives in Lewis’s metaphysical theory.