There are really two questions in this debate. One is about basic ontology (and asks with what furniture, exactly, the universe independent of our minds is furnished), and the other is about particularity.<\/p>\n
\u25aa The issue of basic ontology is whether substances alone should be acknowledged in the real, or whether both substances and<\/em> non-substances (properties, relations) should be acknowledged.<\/p>\n \u25aa The issue about particularity is whether everything that should be acknowledged in the real is particular, or whether something that should be acknowledged in the real is non-particular, that is, common to many, or universal.<\/p>\n The radical nominalists (predicate or concept nominalists) hold (a) that only self-standing things (substances) should be acknowledged in the real and (b) that all such things are particular.<\/p>\n The class nominalists hold (a) that only individuals (substances) and sets should be acknowledged in the real, and (b) that all such items are particular.<\/p>\n The resemblance nominalists hold (a) that only individuals and relations of resemblance between individuals should be acknowledged in the real, and (b) that all such items are particular.<\/p>\n Thus all nominalists insist on a very \u201cparsimonious\u201d ontology (the universe has only one or two kinds of furniture), every item of which is particular.<\/p>\n Particularists agree with nominalists about the particularity of every reality, but they disagree with the nominalists\u2019 highly restrictive ontology. Particularists admit into the real a full range of qualities, sizes, relations, etc. Some particularists also admit substances, so that their world consists of individual substances with their equally particular properties and relations. Other particularists deny substance and explain particular things as stacks of particular properties\/relations.<\/p>\n Realists, of course, admit non-particulars into the real. The most radical realists are called universalists; at the opposite extreme from radical nominalists, they claim that reali-ty consists of universal properties alone, that nothing is particular, and that apparent parti-culars (such as individual substances) are to be explained away as bundles of universals. All other realists admit into the real both particular things and non-particulars or univer-sals.<\/p>\n Platonic realists are transcendent realists. Besides particular things attained by the senses, they admit into the real certain separately existing Forms, attained only by the in-tellect, which transcend particularity and are \u201cmore real\u201d than particulars.<\/p>\n Other realists are immanent realists. Along with self-standing particulars (such as in-dividual substances), they admit non-particular properties and relations as \u201cforms\u201d found within (and between) particulars rather than existing separately from them. For immanent realists, forms or natures are not more real than the particulars they inform.<\/p>\n So much for the parties to the dispute. Let us now look at their positions in more detail.<\/p>\n Common thesis of all forms of nominalism:<\/span><\/p>\n Reality consists entirely of particular things,<\/em> and these do not include properties. Granted, we often speak as if there were properties \u2013\u2013 e.g. we say that a white thing has the \u201cproperty\u201d of whiteness. Yes, and we speak as if the alleged properties were common to many things and hence non-particular. E.g. we say that two white shirts have the same color, that two dogs have the same nature, that an aunt has the same relation to both her nieces, etc. But all these ways of speaking are misleading. Properties are not \u201cin the real.\u201d They are not independent of knowers. Hence common<\/em> ones are all illusory.<\/p>\n But each form of nominalism offers its own explanation of why we talk so misleadingly, why there seem to be real properties, real relations, and common properties\/relations.<\/p>\n Radical nominalisms:<\/span><\/span><\/p>\n \u25aa Predicate nominalism appeals to language in its explanation: particular things fall (individually or pair-wise, triple-wise, etc.) under \u201cnames\u201d or predicates in our language, and many particular things fall (individually or pair-wise etc.) under the same predicate. There are real, particular things, but the illusion that there are properties, common properties, etc., is the shadow of language upon the real. This shirt and that shirt have nothing in common, really, except that both fall under the same word, \u2018white\u2019; this dog and that dog have nothing in common but that both fall under the same noun, \u2018dog\u2019.<\/p>\n \u25aa Concept nominalism appeals to mental entities called concepts in its explanation: particular things fall (individually or pair-wise, triple-wise, etc.) under concepts in our minds, and many particular things fall (individually or pair-wise etc.) under the same concept. There are real, particular things, but the illusion that there are properties, common properties, etc., is the shadow of our conceptual scheme upon the real. This shirt and that shirt have nothing in common except that both fall under the concept, white;<\/em> this dog and that have nothing in common but that both fall under the concept, dog.<\/em><\/p>\n Moderate nominalisms:<\/span><\/span><\/p>\n \u25aa Class nominalism appeals to theoretical entities called sets or classes in its explanation: particular things are members (individually or pair-wise, triple-wise, etc.) of sets, and many particular things are members (individually or pair-wise etc.) of the same set. There are real, particular things, and there are sets of these, but it is an illusion to think that, besides sets, there are also properties, common properties, etc. This shirt and that shirt have nothing in common, really, except that both belong to the set of all white things; this dog and that dog have nothing in common but that they both belong to the set of all dogs.<\/p>\n \u25aa Resemblance nominalism admits that, besides particular things, one must also acknowledge real relations of resemblance. A real particular may bear a real relation of resemblance to another particular, and such a relation is also particular. All other alleged properties are to be explained in terms of resemblance. This shirt and that shirt have nothing in common, really; they just resemble each other, and so we call them both \u201cshirts,\u201d call them both \u201cwhite,\u201d etc. Alternatively, they both resemble a particular shirt or white thing which we think of as a paradigm shirt or a paradigm white thing. We call the two shirts white because they each resemble the paradigm white things as much as those things resemble each other. Ditto for this dog and that dog: they resemble each other, or they resemble certain objects which we think of as paradigm dogs.<\/p>\n If you become convinced that the colors of things, their sizes, their shapes, and many other features of them (including many relations in which they stand to each other) must be admitted into the real in order to explain their resemblances, their causal abilities, etc., then you abandon the nominalist program of ontology as too \u201cparsimonious\u201d to be true. But you may retain the conviction that everything in the real, in whatever category, is fully particular. This shirt, you may say, has a real quality of whiteness, but this quality is every bit as particular as the shirt itself. The whiteness of this shirt is not the whiteness of that one. The canine nature of this dog is not the canine nature of that one. Each dog has a particular case of dog-nature, just as each shirt has its own particular whiteness or case of whiteness.<\/p>\n But now, if each particular animal has its own particular nature, why do we group some together as dogs? If each color quality is utterly particular, why do we group some of them together as cases of whiteness (indeed, cases of exactly the same shade of whiteness), etc.? For want of an answer, some particularists resort at this point to conceptual or resemblance nominalism. We abstract from the particularity of this whiteness and that whiteness to form the concept of whiteness, and this abstracted concept is \u201cpredicable\u201d or common to many. So, certain cases of color fall under our concept of whiteness, and that is all they have in common. Or some cases of color resemble what we consider a paradigm case of whiteness enough to be called \u201ccases of whiteness.\u201d<\/p>\n According to some scholars, Aristotle and Aquinas were particularists who completed their account with concept nominalism.<\/p>\n Platonic or Transcendent Realism<\/span><\/p>\n Platonism admits that particular things are in the real and that that these things have natures, colors, shapes, sizes (and maybe relations). But unlike particularism, Platonic realism denies that these particularized properties of things are basic, irreducible entities. Platonists propose to explain these properties away by positing (a) separate entities called Forms, such as Whiteness Itself, Triangularity Itself, and Dogness Itself, which are intrinsically universal, and (b) a relation called \u201cparticipation\u201d which each particular bears to some number of Forms. The sensible properties of particulars are thus explained as their \u201cshares\u201d in the Forms, and the common color of two white shirts, like the common nature of two dogs, is explained by the fact that both particulars participate in exactly the same Form. To change the metaphor, the common apparent properties of things are the shadows of the Forms upon the transient, ever-changing world of particulars. The particulars are transient because they are composed (of matter and of many shares), and so they can break down. The Forms are permanent (or even eternal) because they are uncomposed. White-ness Itself is nothing but being-white. Thus, as more permanent, the Forms are more real than particulars, more being-like.<\/p>\n Universalism<\/span><\/p>\n If a Platonist decides that particulars themselves are as shadow-like as particularized properties, he may wish to dispense with particulars altogether. The result will be the view that all real beings are universal forms, and what we ordinarily think of as particular individuals are just bundles of universals. What appears to be \u201cthis shirt\u201d is just a bundle of Whiteness, Clothness, Two-sleevedness, etc. The same universal form, Whiteness, appears in the bundle which is (or seems to be) this shirt and in the bundle which is (or seems to be) that shirt. No two bundles are exactly alike in that each differs from every other by the presence or absence of at least one universal form. Thus Universalism is the \u201cflip\u201d of substance-less particularism.<\/p>\n Immanent Realism<\/span><\/p>\n Some scholars hold that Aristotle (and maybe Aquinas) was a genuine immanent Realist. Immanent realism holds that there are real particulars (substances) with real properties of many kinds (drawn from the categories of accidents), and that each of these real properties is particularized in one aspect (its being-in-this or being-in-that) but universal in another aspect (its inner structure as a form). Thus a white thing is white thanks to the form of whiteness, but this form has no separate existence outside the white things, and there is no relation of \u201cparticipation\u201d between the things and the form. Rather, the form is within each white thing. Ditto for dogs and the form which is dogness or canine nature. We do, of course, abstract from Fido and Rin-tin-tin the concept of dog,<\/em> and it is this concept which is predicable of many and \u201cformally\u201d universal according to the being which it has in the mind (namely, its being thought). But the very form itself which is<\/em> thought is<\/em> also in Fido and is<\/em> at the same time in Rin-tin-tin; hence it is (materially) universal.<\/p>\n So which scholars are right? Was Aristotle a pro-substance particularist or an immanent realist? Was Aquinas a pro-substance particularist or an immanent realist?<\/p>\n The following is my answer.<\/p>\nI. The Parties to the Debate<\/h3>\n
II. Nominalism<\/h3>\n
III. Particularism<\/h3>\n
IV. Realism<\/h3>\n
The immanent realism of St. Thomas set forth in 12 propositions.<\/h3>\n