Nominalism is a philosophical doctrine which considers that concepts are human constructions and that the names which relate to them are only conventions of language. Beings are not intrinsically carriers of the concepts by which we apprehend them.
For example, the term “man” does not mean any essence of man in general. Formulated by Roscelin, nominalism was born in medieval scholasticism as a possible answer to the problem of universals: do the words refer to general states of existence endowed with a real ontological existence? Nominalism maintains that names are only instruments for conveniently describing the real.
Nominalism resembles the conceptualism of Pierre Abélard, with which it can be confused. Conceptualism postulates abstract general states, based on a singular reality: concepts. This definition of general states of existence as abstractions brings him closer to nominalism. But conceptualism moves away from nominalism in the sense that concepts are not simple names: they are real forms, specific operations of thought.
Nominalism is sometimes called Occamism, named after William of Ockham, the main thinker of this late school of scholasticism. He has inspired various authors such as Thomas Hobbes, Pierre Gassendi, George Berkeley, John Locke, Emmanuel Kant, William James, David Hilbert, Ludwig Wittgenstein, Rudolf Carnap, Nelson Goodman or even Peter Singer.
It is opposed to essentialism which consists in thinking that natural objects are intrinsically carriers of an ideal essence which transcends them. The idea, or the concepts, have an independent existence which preexists the objects to which they relate. It is also opposed to realism.
The nature of universals
The problem which gives rise to nominalism is that of the nature of universals in Aristotle’s syllogisms (for example, in: all men are mortal, what is the nature of man?). It can be attempted a synthesis which gives a prime importance to the subject, in relation to the object. Nominalists reject the Platonic idealist conception (also called realism in the thesis: universalia sunt realia ante rem), according to which they have an immanent existence a priori, and oppose it that these universals are defined essentially by their names (“nomina”). Therefore, nominalists grant no universality to the concepts of the psyche, apart from the mind that observes them.
In this sense, the philosophical systems of Epicurus, William of Ockham, George Berkeley, David Hume, John Stuart Mill can be qualified as nominalists, because they do not attribute universality to transcendent categories, but simply to what is constructed by the mind of the observer, as also constructed by contemporary linguistic analysis. For them, the particular exists, and the general is only a human invention established for our convenience of reflection.
Paul Valéry pointed out, much later, in the same state of mind, that nature does not know the expression “etcetera”, and that the latter is specific to the perception of the human mind, which does not like prolixity. Automatic classification and “data mining” taught (in the 1990s) to machines to build the equivalent of their own universals.
The main “realist” opponent of nominalism is Guillaume de Champeaux.
Bertrand Russell observes that today, we would readily permute these two appellations, since the “realists” prove to handle in truth above all words, while the “nominalists” only want to use them by referring to the real.
Nominalism also finds many relays in contemporary analytical philosophy. Nelson Goodman endeavored to develop a nominalist language that only appealed to individual realities.
Forms of nominalism
In its maximalist form, practically equivalent to solipsism, nominalism assumes that nothing exists except what an individual perceives. All the thoughts of an individual form a coherent whole, which it is impossible for him to really and consciously analyze.
In a more moderate light, he recognizes an independent existence in (at least) certain objects, but considers that this existence is devoid of practical effect as long as the subject does not manage to consciously integrate the thought. So, for example, for man only the animals he named at creation “exist”, and, as long as the concept of “microbe” and the word “microbe” were foreign to him, he was internally troubled and faced with so many mysteries; mysteries, however, solved, not by the act of naming such “mysteries” “microbes”, but well after having illustrated the imputability of a phenomenon to a tangible and observable category of organic life, which could be named by the man.
Scientific nominalism questions the value of scientific knowledge: is it truths (discoveries) or arbitrary conventions (constructed) by certain scientists? If this were true, it would give scientific knowledge the same perceived and estimated “value” (from an observable point of view) as human language.
The challenge of nominalism
Martin Heidegger is a philosopher who, in modern times, has most contested nominalism, accusing it at the same time of leading straight to the “forgetting of being” and of encouraging “nihilism”.