Journal of the History of Philosophy

In this book, Matthew Duncombe argues that Plato, Aristotle, certain Stoics, and Sextus Empiricus each held a broadly "constitutive" view of relativity. According to constitutive [End Page 688] accounts, a "relative" (one relatum in a relation) is constituted by the relation that it bears to its "correlative" (the other relatum in that relation) (3, 14). Such treatments of relativity sharply contrast with more familiar nonconstitutive accounts, according to which standing in some relation suffices for being a relative. On such a view, versions of which many scholars have assumed to be at work in antiquity, Alcibiades counts as a relative because he is related to Socrates through the "is more beautiful than" relation. On constitutive views, by contrast, only items like "the more beautiful thing"—items that are such that being them depends only on bearing a relation to something else—count as relatives. This book argues that such a view, foreign and ontologically fine-grained though it is, underlies ancient philosophical thinking on a large variety of topics. Duncombe convincingly shows that a proper appreciation of this view allows us to make new progress on certain longstanding interpretive issues in the texts he discusses.

The book's introduction distinguishes the constitutive account from several nonconstitutive ones and helpfully details some of the formal features of constitutive relatives. For instance: if x is relative to y, then (i) x relates only to y (exclusivity) and (ii) y is relative to x (reciprocity) (16–17). Chapter 2 then proceeds to show that these formal features of constitutive relativity are at work in a variety of passages in Plato. The varied nature of the passages Duncombe surveys makes for a strong initial case that Plato holds a constitutive view, but the exegetical value of the project becomes most apparent in the following two chapters, where Duncombe shows that an appreciation of constitutive relativity makes available attractive solutions to two major interpretive cruxes. In chapter 3, Duncombe shows that a constitutive account provides us with a reading of the "Greatest Difficulty" at Parmenides 133c–134e—a challenge to the theory of the Forms that has been described as "almost grossly fallacious" (52)—on which that argument is valid and does not beg the question against proponents of the Forms. The following chapter then considers Plato's argument for the separation of reason from appetite in Republic book 4. Duncombe first shows that the question whether this argument produces either too few or too many soul parts amounts to the question whether certain opposite relatives relate exclusively to the same thing. He then persuasively argues that, on Plato's constitutive view, the relevant opposites—thirst and aversion to drink—do so. However, as Duncombe points out in the conclusion of this chapter, this view about opposite relatives forms an inconsistent set with the two key formal features: exclusivity and reciprocity. Here I worry that Duncombe's "tentative" solution to that problem—that the linguistic expressions for correlatives in such cases are ambiguous (88)—undermines his elegant answer to the issues that this chapter set out to solve. According to such a picture, thirst relates to drink (relative to thirst), whereas aversion to drink relates to drink (relative to aversion to drink). However, on this view, although thirst and aversion to drink respect the formal features of reciprocity and exclusivity, they no longer appear to relate to the same thing, raising yet again the worry that the partition argument produces either too few or too many soul parts.

Chapter 5 transitions to Aristotle and surveys his explicit treatment of various formal features of constitutive relativity in the Categories, Topics, and Sophistical Refutations. Duncombe's aim here is "exposition and problem solving rather than a diatribe in favor of the constitutive reading" (116), but a fuller, more polemical treatment of Aristotle's discussion of babbling in the Sophistical Refutations could have helped his case. After all, Aristotle's remark in that passage that "one ought not to allow that predications of...