Any view which analyzes a given subject-matter in terms of words or language, derived from the Latin ‘nomen’ meaning ‘name’, ‘term’ or ‘word’.
A nominalist view of universals (see Platonism) says they are neither substantive realities (realism) nor mental concepts (conceptualism). Rather, they are simply words which we apply to a group of objects; the members of the group owing their membership to resembling each other in some relevant respect. (But this leads to difficulties: is not resemblance itself a universal? And what about the respect in which the resemblance holds?)
A nominalist about definitions says there can only be nominal definitions (accounts of how a word is or should be used), not real definitions (analyses of a concept or thing which the word is supposed to stand for: ‘res’ is Latin for ‘thing’).
A nominalist about modalities says there are only de dicto, not de re, modalities; that is, roughly, statements may be necessarily true, but things do not have necessary properties. (Necessarily, a husband has a wife; but no man has the property of necessarily having a wife.)
Also see: conceptualism, particularism, realism
M J Loux, ed., Universals and Particulars (1970)
Ancient Greek philosophy
The opposite of nominalism is realism. Plato was perhaps the first writer in Western philosophy to clearly state a realist i.e. non-nominalist position:
…We customarily hypothesize a single form in connection with each of the many things to which we apply the same name. … For example, there are many beds and tables. … But there are only two forms of such furniture, one of the bed and one of the table. (Republic 596a-b, trans. Grube)
What about someone who believes in beautiful things, but doesn’t believe in the beautiful itself…? Don’t you think he is living in a dream rather than a wakened state? (Republic 476c)
The Platonic universals corresponding to the names “bed” and “beautiful” were the Form of the Bed and the Form of the Beautiful, or the Bed Itself and the Beautiful Itself. Platonic Forms were the first universals posited as such in philosophy.
Our term “universal” is due to the English translation of Aristotle’s technical term katholou which he coined specially for the purpose of discussing the problem of universals. Katholou is a contraction of the phrase kata holou, meaning “on the whole”.
Aristotle famously rejected certain aspects of Plato’s Theory of Forms, but he clearly rejected nominalism as well:
…’Man’, and indeed every general predicate, signifies not an individual, but some quality, or quantity or relation, or something of that sort. (Sophistical Refutations xxii, 178b37, trans. Pickard-Cambridge)
The first philosophers to explicitly describe nominalist arguments were the Stoics, especially Chrysippus.
In medieval philosophy, the French philosopher and theologian Roscellinus (c. 1050 – c. 1125) was an early, prominent proponent of nominalism. Nominalist ideas can be found in the work of Peter Abelard and reached their flowering in William of Ockham, who was the most influential and thorough nominalist. Abelard’s and Ockham’s version of nominalism is sometimes called conceptualism, which presents itself as a middle way between nominalism and realism, asserting that there is something in common among like individuals, but that it is a concept in the mind, rather than a real entity existing independently of the mind. Ockham argued that only individuals existed and that universals were only mental ways of referring to sets of individuals. “I maintain”, he wrote, “that a universal is not something real that exists in a subject… but that it has a being only as a thought-object in the mind [objectivum in anima]”. As a general rule, Ockham argued against assuming any entities that were not necessary for explanations. Accordingly, he wrote, there is no reason to believe that there is an entity called “humanity” that resides inside, say, Socrates, and nothing further is explained by making this claim. This is in accord with the analytical method that has since come to be called Ockham’s razor, the principle that the explanation of any phenomenon should make as few assumptions as possible. Critics argue that conceptualist approaches answer only the psychological question of universals. If the same concept is correctly and non-arbitrarily applied to two individuals, there must be some resemblance or shared property between the two individuals that justifies their falling under the same concept and that is just the metaphysical problem that universals were brought in to address, the starting-point of the whole problem (MacLeod & Rubenstein, 2006, §3d). If resemblances between individuals are asserted, conceptualism becomes moderate realism; if they are denied, it collapses into nominalism.
Modern and contemporary philosophy
In modern philosophy, nominalism was revived by Thomas Hobbes and Pierre Gassendi.
In contemporary analytic philosophy, it has been defended by Rudolf Carnap, Nelson Goodman, H. H. Price, and D. C. Williams.
Indian philosophy encompasses various realist and nominalist traditions. Certain orthodox Hindu schools defend the realist position, notably Purva Mimamsa, Nyaya and Vaisheshika, maintaining that the referent of the word is both the individual thing perceived by the subject of knowledge and the class to which the thing belongs. According to Indian realism, both the individual and the class have objective existence, with the second underlying the former.
Buddhists take the nominalist position, especially those of the Yogacara school; they were of the opinion that words have as referent not true objects, but only concepts produced in the intellect. These concepts are not real since they do not have efficient existence, that is, causal powers. Words, as linguistic conventions, are useful to thought and discourse, but even so, it should not be accepted that words apprehend reality as it is.
Dignaga formulated a nominalist theory of meaning called apoha, or theory of exclusions. The theory seeks to explain how it is possible for words to refer to classes of objects even if no such class has an objective existence. Dignaga’s thesis is that classes do not refer to positive qualities that their members share in common. On the contrary, classes are exclusions (apoha). As such, the “cow” class, for example, is composed of all exclusions common to individual cows: they are all non-horse, non-elephant, etc.
Among Hindu realists, this thesis was criticized for being negative.
The problem of universals
Nominalism arose in reaction to the problem of universals, specifically accounting for the fact that some things are of the same type. For example, Fluffy and Kitzler are both cats, or, the fact that certain properties are repeatable, such as: the grass, the shirt, and Kermit the Frog are green. One wants to know by virtue of what are Fluffy and Kitzler both cats, and what makes the grass, the shirt, and Kermit green.
The Platonist answer is that all the green things are green in virtue of the existence of a universal: a single abstract thing that, in this case, is a part of all the green things. With respect to the color of the grass, the shirt and Kermit, one of their parts is identical. In this respect, the three parts are literally one. Greenness is repeatable because there is one thing that manifests itself wherever there are green things.
Nominalism denies the existence of universals. The motivation for this flows from several concerns, the first one being where they might exist. Plato famously held, on one interpretation, that there is a realm of abstract forms or universals apart from the physical world (see theory of the forms). Particular physical objects merely exemplify or instantiate the universal. But this raises the question: Where is this universal realm? One possibility is that it is outside space and time. A view sympathetic with this possibility holds that, precisely because some form is immanent in several physical objects, it must also transcend each of those physical objects; in this way, the forms are “transcendent” only insofar as they are “immanent” in many physical objects. In other words, immanence implies transcendence; they are not opposed to one another. (Nor, in this view, would there be a separate “world” or “realm” of forms that is distinct from the physical world, thus shirking much of the worry about where to locate a “universal realm”.) However, naturalists assert that nothing is outside of space and time. Some Neoplatonists, such as the pagan philosopher Plotinus and the Christian philosopher Augustine, imply (anticipating conceptualism) that universals are contained within the mind of God. To complicate things, what is the nature of the instantiation or exemplification relation?
Conceptualists hold a position intermediate between nominalism and realism, saying that universals exist only within the mind and have no external or substantial reality.
Moderate realists hold that there is no realm in which universals exist, but rather universals are located in space and time wherever they are manifest. Now, recall that a universal, like greenness, is supposed to be a single thing. Nominalists consider it unusual that there could be a single thing that exists in multiple places simultaneously. The realist maintains that all the instances of greenness are held together by the exemplification relation, but this relation cannot be explained.
Finally, many philosophers prefer simpler ontologies populated with only the bare minimum of types of entities, or as W. V. O. Quine said “They have a taste for ‘desert landscapes.'” They try to express everything that they want to explain without using universals such as “catness” or “greenness.”
There are various forms of nominalism ranging from extreme to almost-realist. One extreme is predicate nominalism, which states that Fluffy and Kitzler, for example, are both cats simply because the predicate ‘is a cat’ applies to both of them. And this is the case for all similarity of attribute among objects. The main criticism of this view is that it does not provide a sufficient solution to the problem of universals. It fails to provide an account of what makes it the case that a group of things warrant having the same predicate applied to them.
Proponents of resemblance nominalism believe that ‘cat’ applies to both cats because Fluffy and Kitzler resemble an exemplar cat closely enough to be classed together with it as members of its kind, or that they differ from each other (and other cats) quite less than they differ from other things, and this warrants classing them together. Some resemblance nominalists will concede that the resemblance relation is itself a universal, but is the only universal necessary. Others argue that each resemblance relation is a particular, and is a resemblance relation simply in virtue of its resemblance to other resemblance relations. This generates an infinite regress, but many argue that it is not vicious.
Class nominalism argues that class membership forms the metaphysical backing for property relationships: two particular red balls share a property in that they are both members of classes corresponding to their properties—that of being red and being balls. A version of class nominalism that sees some classes as “natural classes” is held by Anthony Quinton.
Conceptualism is a philosophical theory that explains universality of particulars as conceptualized frameworks situated within the thinking mind. The conceptualist view approaches the metaphysical concept of universals from a perspective that denies their presence in particulars outside of the mind’s perception of them.
Another form of nominalism is trope nominalism. A trope is a particular instance of a property, like the specific greenness of a shirt. One might argue that there is a primitive, objective resemblance relation that holds among like tropes. Another route is to argue that all apparent tropes are constructed out of more primitive tropes and that the most primitive tropes are the entities of complete physics. Primitive trope resemblance may thus be accounted for in terms of causal indiscernibility. Two tropes are exactly resembling if substituting one for the other would make no difference to the events in which they are taking part. Varying degrees of resemblance at the macro level can be explained by varying degrees of resemblance at the micro level, and micro-level resemblance is explained in terms of something no less robustly physical than causal power. David Armstrong, perhaps the most prominent contemporary realist, argues that such a trope-based variant of nominalism has promise, but holds that it is unable to account for the laws of nature in the way his theory of universals can.
Ian Hacking has also argued that much of what is called social constructionism of science in contemporary times is actually motivated by an unstated nominalist metaphysical view. For this reason, he claims, scientists and constructionists tend to “shout past each other”