Advocates of universals, traditionally called ’realists,’ claim that we need to recognize the existence of abstract, general, and repeatable entities—universals—such as the property of redness or that of squareness. These are required, says the realist, to explain phenomena of qualitative identity and resemblance between concrete individual things, the ‘particulars.’ Opponents to realism, including various kinds of nominalists, deny that we need anything beyond particulars in our ontology. Realists and their adversaries, then, argue over how we are to account for generality in thought, language, and reality.
While this topic has been at issue since at least Plato’s time, its contemporary resurgence in metaphysics is due primarily to the works of D.M. Armstrong and D. Lewis. Following this lead, the present volume includes discussions about universals by contemporary metaphysicians. The book contains nine articles from eminent philosophers, such as P. Van Inwagen, J. Heil, E.J. Lowe, M. Loux, and others. Due to their outstanding quality and technical detail, it is impossible to describe here the full details of each contribution. I will therefore simply outline the most general points of interest of the book.
While realists believe there are general properties or attributes, there is no consensus among them on a range of specific questions, including: are universals causally efficient or inert; and, are universals spatio-temporally located within particulars or do they exist apart from them? One important part of the book is consequently dedicated to analyzing the opposition, drawn in the first articles, between the ‘constituent’ and the ‘relational’ approaches which are available to the realist. A constituent theorist will claim that particulars have a deeper structure than their commonsensical part-whole (‘mereological’) structure and that it is what gives them the features they have. On that view, what underlies and explains the character of familiar objects are underived fundamental constituent parts: immanent universals or intrinsic properties. The relationist, on the contrary, denies that objects have such metaphysical structure. She argues that particulars have the features they have in virtue of the peculiar relation they bear to the non-spatio-temporal universals of which they are instances.
In his article, M. Loux points out that the relationist approach has generally been preferred to its rival on the ground that it seems fundamentally mistaken to posit abstract entities as being parts of concrete things. Loux responds to this objection and a few others, before setting forth an Aristotelian constituent approach, which he deems immune to these reproaches. P. Van Inwagen and E.J. Lowe, on the contrary, defend relationism, the former by arguing that little sense can be made of the constituent’s talk ‘ontological structure’ and the latter by showing that Aristotle set the ground for a (relationist) four-category ontology, which proves more fruitful than his better-known (constituent) hylemorphic theory. G. Galluzo, finally, argues that we need to distinguish between what-universals (‘kinds’) and how-universals (‘properties’), the former being irreducible—and metaphysically prior—to the latter. He defends, on this ground, an ‘Aristotelian’ understanding of kinds, against advocates of transcendent universals (‘Platonists’).
Another important part of the book is devoted to the discussion of ‘trope theory’ (TT), which is rather recent addition to the debates surrounding universals. A trope is an ‘abstract particular.’ In other words, it is a specific case of a general characteristic, such as a particular instance of roundness exhibited by a given object. It is often claimed that TT is a satisfactory course between strict nominalism and traditional realism. Like the former, it is committed to a parsimonious, monocategorial ontology of particulars, but it retains the explanatory power of the latter, by admitting the existence of properties. Standard TT indeed accounts for generality by construing properties in terms of resembling—yet distinct—tropes. Advocates of tropes, thus, reject the traditional dichotomy between concrete particulars and abstract universals. For them, there are only particular properties.
In his contribution, J. Heil argues that the idea of a particular property traces back to classical metaphysics. Against standard TT, he argues that particulars prove irreducible to ‘bundles’ or collections of tropes. Yet he admits that realist talk of properties can be accounted for in terms of modes, i.e., particularized ways things are. The best ontological picture would thus consist in substances plus modes, forming an interesting alternative both to mainstream TT and realism. R.K. Garcia argues that there is an important yet largely unperceived ambiguity within TT. Some have construed tropes as individual properties (say, the roundness of a specific ball), while others have seen them as propertied individuals (the round individual itself). From this distinction between ‘modifier’ and ‘module’ tropes, Garcia shows that distinct ontologies have been implicitly competing in the literature, each having their own strengths and defects. Finally, S. Gibb convincingly defends TT against an objection frequently raised against it, namely that it cannot, unlike universals, account for the generality of natural laws.
A last remarkable feature of this book is that it shows clearly how philosophically central the problem of universals is. While all contributions show that universals connect with other fundamental metaphysical questions—persistence and identity, material composition, essence and modality—the last two articles are specifically dedicated to exploring this theoretical overlap. F. McBride shows how technical matters about the nature of non-symmetrical relations come into play in the debates surrounding realism. A-S Maurin argues that ‘states of affairs,’ which have often been seen as what makes possible the unification of abstract properties and concrete particulars, eventually fail to do the job. She thus provides a compelling argument against the existence of states of affairs in general.
This is a great volume, the kind anybody working in or interested in contemporary metaphysics should read. Its main lesson is that the traditional categories of realism and nominalism should be drastically refined. It also exemplifies how perennial problems, far from being left to historians of ideas or ‘overcome’ by science and logical analysis, have been refined by analytic metaphysicians with impressive rigor and constant inventiveness. After finishing the book, one cannot help but think that the problem of universals remains of utmost importance to contemporary philosophy and that it should therefore not be ignored.
