In Nicomachean Ethics V.7, Aristotle claims that political justice (to dikaion politikon) possesses a “natural” (phusikon) pail and a “conventional” (nomikon) part In response to those who separated nature and convention and disparaged the latter because it was different from place to place, Aristotle claims that both nature and convention admit of variation, and his language suggests that the two are ultimately parts which need to be interwoven or combined. Scholars who have struggled with Aristotle’s apparently disparate senses of the idea of nature have assumed that nature is an ethical ideal which can be separated from and serve as a guide for that which is merely conventional. I argue that when Aristotle invokes what is “natural” as a norm, he does so under the assumption that the natural component of a norm is ultimately separable from its conventional part only in abstraction. Just like the syllable “BA” is not reducible to the letters “b” and “a,” but instead is a whole greater than its two parts, political justice is a composite unity of nature and convention which, in unifying the two parts, transforms them.
To defend my solution to the problem of the apparently inconsistent senses of nature which Aristotle uses in his practical philosophy, I first survey the different ways which Aristotle uses the terms phusis and nomos (and their cognates) in his Ethics. Although it is true that Aristotle distinguishes between “mere nature” and “ethical nature,” there is a third relevant sense of nature at play in the Ethics, namely that which is usual or universal, and it is necessary to explain the place of generalizations about human nature within the Ethics. Second, I show that the different sense of phusis and nomos are in fact interrelated through an examination of Aristotle’s account of ethical habituation, since it is the laws and customs of a society which transform mere nature into ideal nature. Third, I argue that the account of phusis and nomos in EN V.7 illustrates how the two concepts are entwined into a composite unity. Although Aristotle may never explicitly distinguish the different senses of nature in his Ethics, right in the center of the Ethics he does explain the relationship between phusis and nomos, and I argue that EN V.7 is proof that he does not conceive of nature as a source of positive normativity independent from convention. Finally, in my conclusion I claim that when nature is isolated from custom, it only supplies prohibitions about what is forbidden rather than guidance about what one should do.
Lockwood, Thornton C., "Physis and Nomos in Aristotle's Ethics" (2005). The Society for Ancient Greek Philosophy Newsletter. 327.