"Nominalism, as it is commonly understood, is the philosophical view in which universals are regarded as having no objective weight, and no intrinsic correspondence to individual, concrete things. For instance, according to Nominalism, to say that Peter has a human nature and that John has a human nature is simply to say that both have extrinsically predicated of them a common name (nomen), which happens to be “human nature.” To predicate the same ‘human nature’ to both John and Peter is not to say that they share any metaphysical reality or nature in common; it is simply to say that we predicate something common to both on the basis of observation. The common features that are shared by John and Peter (e.g., intellect, will, arms, legs, nose, etc.) do not and cannot, from a Nominalist point of view, be understood to be based upon a common shared ‘human nature’ except in name. There is no ‘human nature’ that transcends or norms what it means to be human in anything more than an extrinsic sense; in other words, human flourishing is not based on an objective human nature that exists apart from the collection of individual beings called human, but can be only something imposed onto this group of individuals without any inherent reason that corresponds to their given nature (e.g., for vegetative beings, flourishing would be to grow physically and to do it well, while for rational beings, flourishing would pertain not only to physical growth, but also growth in knowledge and love of truth and goodness—this based on the objective nature of the being in question).
A common illustration used to explain Nominalism is found in the use of paper currency. Unlike coins that may be made out of silver or gold, carrying a value that corresponds to its ‘nature,’ paper currency, has a value imputed to it extrinsically. On this basis, a $100 bill would be identical to a $10 bill in nearly everything except for the fact that one is deemed to be worth several times more than the other—solely on the basis of what some authority judges. There is nothing intrinsic to the paper bill that gives it its value. The problem arises when this mode of understanding of the nature of things is applied across the board to human nature and other universals.1 According to Nominalism, observations are made, a name is given from said observations, but this name has nothing to do with a shared nature or ‘essence’ of the thing, as such.2 Such a process of exclusively extrinsic denomination stems from a radical emphasis on the reality of the particular accompanied by an explicit denial of an objective universal shared reality inherent to things.3
According to classical philosophy, by contrast, given the link between particular, concrete things and corresponding ideas or universals (whether these ideas or universals were thought to exist independently of the concrete individual or in conjunction with it), the ideal was seen to be something objective, rather than a result of extrinsic imposition. From a Nominalist perspective, focusing as it did solely on concrete and individual realities to the exclusion of the immaterial aspects of material things, and a fortiori anything purely immaterial, metaphysics as the study of being qua being (i.e., not necessarily material and therefore distinguishable from the empirical or sensible reality) could only appear as the height of speculative arrogance.4 Such a view of metaphysics in the traditional sense remains today, not only within Protestantism, but also pervades our post-Enlightenment setting."5
1 And even in the case of paper currency, problems arise if there is no real corresponding value; the absence of an objective correspondence leads to problems like inflation. So this example is also imperfect as the extrinsic denomination is not based on pure will, but on some objective value.
2 This is not to say, however, that realists, such as Thomas, for example, believe that there is a separate form existing somewhere that is human nature (a view typically associated with Plato). Rather, it is simply to say that the shared nature between John and Peter corresponds to something inherent to both, and this shared nature is objective. Its existence is not the result of merely an extrinsic recognition followed by an arbitrary naming process; on the contrary, the name follows from a reality discovered to be present in both Peter and John.
3 Cf. with Aquinas’s treatment of man’s knowledge in ST I, q. 94, a. 3, s.c., where he asks whether the first man knew all things. Aquinas argues from the fact that Adam named the animals that he had to know the very natures of the animals, “Nomina autem debent naturis rerum congruere.” That is, the names should be congruent with the nature of the thing. This is a way of thinking about creation that is absolutely foreign to the view of Nominalism.
4 And the logical outgrowth of this is evidenced in later thinkers such as Hume and Kant, who have influenced all of subsequent philosophy, for better or for worse. Cf., Roland H. Bainton, Here I Stand: A Life of Martin Luther (New York, NY: 1995), 166-79. As Bainton recounts: “The Occamists had wrecked the synthesis of Thomas Aquinas whereby nature and reason lead through unbroken stages to grace and revelation. Instead, between nature and grace, between reason and revelation, these theologies introduced a great gulf. So much so indeed that philosophy and theology were compelled to resort to two different kinds of logic and even two different varieties of arithmetic” (169).
5 For varied accounts of the relationship between Nominalism, the Reformation, and secularization cf., Bradley Gregory, The Unintended Reformation: How a Religious Revolution Secularized Society (Cambridge, MA: Belknap Press, 2012), Alisdair MacIntyre, After Virtue: A Study in Moral Theory (Notre Dame, IN: University of Notre Dame, 2007), Charles Taylor, A Secular Age (Cambridge, MA: Belknap Press, 2007), and Michael Allen Gillespie, The Theological Origins of Modernity (Chicago, IL: University of Chicago, 2009).