The Problem of Universals: a Somewhat Brief Introduction

The following is a repost from a recent article on Pat’s Substack.

The problem of universals is sometimes called the problem within philosophy and for good reason. The consequences of one’s position concerning universals has rather significant consequences, though many such consequences are not immediately clear. One might argue – in fact, many have argued – that denial of universals leads to a most troubling skepticism, perhaps making knowledge impossible. Arguably this was Plato’s reason for positing his heavenly realm of forms (universals); that is, to provide the necessary conditions for knowledge, rationality, and meaningful communication between beings like us. Here I am assuming background familiarity with this debate – I apologize for that. Let’s slow down a bit.

The question for getting us into the problem of universals, as Jeffrey Brower states it, is this: Are distinct things members of the same kind in virtue of sharing a universal?

Realists say yes because there are universals. Nominalists say no because there are no universals.

If we answer yes, we nevertheless remain unsure what to make of universals, which include not just concepts such as triangularity, but propositions, and mathematical thought, and possible worlds, and so on. Do they have some independent existence of their own, in a Platonic heaven of sorts? (Extreme Realism) Are they merely “in” the particulars themselves and then abstracted by us? (Moderate Realism) Or are they in the particular objects, abstracted by us, but somehow ultimately grounded in the mind of God? (Scholastic Realism).

Before wading into that, let’s motivate the problem a little further.

Take two triangles drawn on the chalkboard. Naturally, we think of these both as triangles. Why? Well, presumably because they share some feature or characteristic or pattern in common. What is that? Naturally, again, the response is to say they share triangularity in common, which is understood as a universal notion, since it transcends material particularity and is exact and determinate (read: unambiguous) in conceptual content. It is that common pattern, if you like, of triangularity, that realists are inclined to say is that in virtue of which these two particular triangles are members of the same kind. Again, such patterns are called universal because they are “abstract”– that is, considered apart from particularizing features of the concrete objects that exhibit them. Particularizing features such as being drawn in chalk or carved in wood or painted a certain color or being located at a certain space-time point.

Being abstract, universals are not something we can encounter while walking in the woods. That is, we never “bump into” triangularity out in the wild like we do turkeys; at most, we only encounter this or that particular triangle, just as we encounter this or that turkey, but not “turkey-ness” as such. Moreover, any particular triangle, however precisely drawn, never fully lives up to the exact and determinate nature of triangularity as such – never has perfectly straight sides or angles that add up exactly to 180 degrees, or what have you. All concrete particular and physical objects are always imperfect and can only ever approximate universal notions.

Returning now to the primary positions in this debate, the realist (in some way or another) affirms universals, whereas the nominalist denies them. Nominalism has certain attractive features – minimally, it commits one to less categories (or subcategories) of reality, and is thus a leaner theory in certain respects. But leaner theories are sometimes explanatorily inadequate, and this appears to be the case with nominalism given that realism is primarily motivated for its necessity to make sense of knowledge, rational belief, meaningful communication, and so on.

I will not rehearse the entire battery of arguments against nominalism and for realism here. If somebody wants a useful summary, they should consult chapter 3 in Edward Feser’s book 5 Proofs for the existence of God. My personal view is that nominalism does suffer from issues of self-defeat or does tend toward an irremediable skepticism or both.

However, to give a flavor of these sort of arguments against nominalism, we could begin by considering an objection from David Hume against realism, who says, “Let any man try to conceive a triangle in general, which is neither isosceles nor scalene, nor has any particular length or proportion of sides; and he will soon perceive the absurdity of all the scholastic notions with regard to abstraction and general ideas.”

Hume’s mistake is in failing to differentiate between understanding or conceiving and perceiving or imagining. Of course, one cannot picture or imagine (“image”) a triangle without engaging the sense power and thus having the picture become bound (particularized) as either isosceles or scalene or red or white, but that is not what understanding is about, and Hume is overlooking the difference between intellect and sense – a distinction made explicit among scholastics. For we obviously can and do conceive of triangularity by understanding (not picturing) what is common to all particular triangles, be they isosceles or scalene, red or white, drawn in chalk or ink, etc.

Moreover, we have every right to ask why we call such particulars (this triangle, that triangle) by a common name (triangle), and what other reason could a person provide aside from the fact they share characteristics in common (namely, triangularity, trilaterality, etc.)? If we admit to understanding such characteristics then nominalism is refuted because we have just conceded to having a universal and determinate understanding of something (such as triangularity) apart from particulars (being isosceles or scalene, drawn in chalk or ink, etc.), which is what various nominalists and skeptics (like Hume) deny. Further, if we do not admit to understanding such characteristics then there is no basis for calling various particular things all triangles in the first place – which is required for Hume to get his objection started. Ironically, it appears that Hume demonstrates both the reality, and his understanding of, universals (triangularity) in his very attempt to refute them, else his assertion is meaningless. Hume is confusing picture thinking (sense power) with conception (intellectual power). The scholastics are not impressed.

Ed Feser summarizes the self-defeat issue for nominalism, the position which denies the reality of universals, as follows,

“… where we think there are universals, the nominalist says, there are really only general names, words we apply to many things. Hence, there is, for instance, the general term ‘red,’ which we apply to various objects but no such thing as redness. Of course, this raises the question why we apply the term ‘red’ to just the things we do, and it is hard to see how there could be any plausible answer other than ‘because they all have redness in common,’ which just brings us back to affirming the existence of universals after all. The nominalist might seek to avoid this by saying that the reason we label different things ‘red’ is that they resemble each other, without specifying the respect in which they resemble each other. This is implausible on its face – isn’t it obvious that they resemble each other with respect to their redness?”[1]

Did you notice resemblance is itself a universal?.

So, there are considerations along those lines (again, see Feser’s book for further development). But there are other skeptical consequences that loom large for the nominalist as well.

For example, suppose Jack and Jane are discussing the concept of justice. How do we know they are discussing the same thing? How do we know that what Jack means by justice is the same thing that Jane means by justice? If there is no universal justice that our concepts either can or cannot fail to adequately capture or conform to, then it becomes difficult to see how meaningful communication is possible between parties. If, however, meaningful communication is possible between parties, it seems that can only be possible because some form of realism is true. But the problem is worse than that. Let’s get rid of Jane and consider just Jack. Jack is thinking about justice at T1 and then Jack is thinking again about justice at T2. Is Jack thinking about the same thing? If so, how can that be? Jack’s brain state (or whatever) is not the same at T2 as it was at T1. All the physical particulars at T2 are different than at T1, whatever you might identify the relevant particulars to be. If everything is particular (and there are no universals) then it seems it might be impossible to step into the same thought twice, as it were. But for knowledge and rational thought to be possible, we must be able to think in a continuous fashion and hold stable concepts – that is, through change. Otherwise, we cannot run validly through various argumentative steps.

Of course, these scenarios are not only deeply skeptical but self-defeating, since they would undermine any basis for arguing for anything, let alone nominalism. This, of course, is what leads to the absolute skeptic, in trying to live consistently, simply having to lie down and wiggle his little finger in response to people wondering if something is seriously wrong with him. But of course, even wiggling ones’ finger, presumably, is responding to terms they find meaningful – so even that is not entirely consistent with their underlying skepticism.

At this point – and consider this a brief aside – traditional thinkers have seen the above as reason to maintain that the intellect is itself immaterial, because our ability to possess universal concepts is incompatible with physicalism or materialism. After all, if all material things are particular and no universal is particular, then how could a worldview which is materialist/physicalist accommodate universals? It seems the materialist would be committed to nominalism (as many if not most materialists are) but if nominalism is false then materialism must be false also.

In other words, we can know and entertain the concept of triangularity and do not rely on any restricted mental image to do so, because such images (as we argued along with Hume) will always be particular and therefore not universal (to some degree imperfect). We grasp what triangularity is and this grasping transcends the material because everything material – including brain states – is particular. One is not reducible to the other. Hence, at least some of our thinking cannot be entirely material. Because our thoughts are something no material thing can be (universal, and, as we’ll see, determinate or exact in conceptual content) our thoughts cannot themselves be material.[2]

In this sense, even if we cannot think without our brains, we do not think (understand) with our brains. Our brains, while perhaps a necessary condition, are not themselves a sufficient condition for the functioning of the human mind at least in relation to formal thought and conceptual content.

So much for that “brief aside.”

All the above to say is that some form of realism appears not only correct but necessarily so to avoid catastrophic skepticism. We have not, however, answered just what brand of realism that is. Such is a topic I hope to consider in a later article.

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[1] Edward Feser, Five Proofs of the Existence of God (San Francisco: Ignatius Press, 2017), 92-93.

[2] The argument is that if thought has property x, and property x cannot be material, then thought cannot be material.