Best argument for the reality of the universals?

Nominalists/Empiricists (they are fundamentally the same ) often argue against the reality of universals, affirming that every universal that is in our mind comes from our total experience of particulars.
How would you respond?
The best counter-objection that comes to my mind is that, if universals didn’t exist outside our mind, every objective knowledge would be impossible. Unfortunately, many of them agree and find no problem with falling into mere subjectivism.
What do you think?

What do you mean by “objective knowledge” and “subjectivism” in this case?

Objective knowledge = knowledge of reality as it is, indipendently from any opinion
Subjectivism = the idea that every knowledge is subjective (basically, just an opinion )

Why do you think someone can know “reality as it is, independently from any opinion”?

How can someone know something if they are not the suject of the act of knowing?

I ask these not to dispute your claims, but to clarify your position.

What I mean is that we can know reality as it is in itself (contra, for example, Kant, who affirmed that things in themselves are unknowable because we can’t know if our sense and intellect can tell us something real about them ).

Yes, this argument is strong, but it is unlikely to cause your opponents as much discomfort, as it should.

But there might be a way around their defences. :slight_smile:

Pose a seemingly unrelated puzzle (perhaps a bit later, so that they would not see the connection until it is a bit too late). Ask them what is two plus two. Now, the consistent nominalist should say something like “It depends.”, but that would make him look like a fool (and he does not want to look like a fool), and so most likely he will answer “Four.”. Then ask him what this proposition (2+2=4) refers to (it might be a good idea to illustrate what is meant by “refers” by asking what proposition like “Everest is in Asia.” refers to - Everest and Asia). Point out that if it refers to concepts in one’s mind, then you two are affirming different propositions, which would look silly. Perhaps it would be best to let him think about it.

From my time at university “wasted” in the philo department, universals exist because you can’t find an exception to them. I suppose that would be experience-driven, to use your language.

When you have a repeatable experience that contradicts a universal, you’ve broken it, showing it is no longer universal, but particular.

The experience of particulars seems to be “universal” experience. How do they explain the universal of love?

That is, of course, unless they have not experienced it…

Ed Feser presents some good arguments in Five Proofs of the Existence of God, specifically in his third proof based on an Augustinian argument from our ability to abstract, have language, etc…

Your question has been on my mind as well, recently. I’ve been slowly plugging my way through John Frederick Pfeifer’s The Concept in Thomism, which presents a Thomist epistemology as developed by John of St. Thomas. So far it isn’t a direct argument against anti-realism so much as it’s a presentation of how Thomists understand knowing and knowledge (hylemorphism is key to this), though I can draw some corrolaries myself. I have a couple other Thomist epistemology books on my shelf, but I haven’t had as much time to read as I would like.

Certainly contra Descartes, Kant, Locke, Hegel, etc… Thomists hold that the objects of our thoughts are the external objects themselves, not just our mental representations of them. So it’s not an argument over how true the mental representations are, but a more fundamental disagreement. (St. Thomas himself was aware of predecessors and contemporaries of his day who claimed that thoughts (and not external objects) are the objects of our thoughts, that wasn’t something invented later, even if it wasn’t as developed as people like Kant and Locke would make it. Later Thomists in reaction to Locke and Kant certainly had to address the questions they brought up.

Here I am posting away without giving any arguments. But it is something I’m definitely interested in.

Here’s something I read through awhile ago when I first started studying the topic that piqued my interest, though it may not be directly what you are looking for.

http://www.catholicapologetics.info/catholicteaching/philosophy/askeptic.htm

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That is not what is meant by “universals” here. The subject concerns things talked about in, let’s say, https://plato.stanford.edu/entries/universals-medieval/.

To use the example used in there, the problem of universals is a bit like this: how can we prove theorems that hold for all triangles, when we can observe a very finite amount of things that, furthermore, are not perfectly triangular? And yet those theorems are “approximately true” for those “approximately triangular” things.

Upon a quick read, it is the same thing. Just one of the many different presentations of the same problem, as said in your link.

A universal holds because you can’t break it. There is no exception to be found. It is based on observation. The pythagorean theorem holds because I just can’t break the darn thing. Ergo it can be assumed to be universally true.

Once upon a time, universals were called laws. Laws of science and philosophy. That’s not in vogue anymore.

The concept of universals can be quite nuanced. There are distinctions made the realism of universals (more broadly) and the realism of abstract objects. There are those who are anti-realists when it comes to universals but realists when it comes to mathematics, or anti-realist for both. It’s an important topic specifically for theories of knowledge and for the idea of “concepts.”

Is the concept of an oak tree a universal? The concept of being human? The concept of golf? The concept of a hydrogen atom? What about propositions? “Snow is white” for example. And more. It might be easy to say no, but that does call into question the power of science, the existence of logic, the idea that we can communicate by language, what and how we can know things, and more. These aren’t issues that can just be ignored by an anti-realist (and there are anti-realists who try to address these issues).

What universal do you share with an empiricist that they will recognize as something shared with you?

Basically, you need something in common if you are going to agree that there are things that we all have in common. (universals) Logic, mathematics, etc. might provide answers, but it is going to depend on the empiricists.

Unless you know some principle they all share in common. Then you might try that.

Well, “universals” are a bit more than just “laws”. They also include “Platonic Forms”, essences.

I must have been lucky with my professor.

"Can you think of an exception to it? Can anyone, including people smarter than you? Has the idea been around long enough for the gallery to have its fair shot?

If it endures, then it’s likely a universal"

That was the essential lesson and even after your article, I still think it fits.
One caveat - He was also a believer in a lack of complete certainty. You can never be certain of anything with perfection, even universals. So if you want to be technical, universal statements are served up with “To our very best knowledge…”. (a la the Gettier Problem)

It was good enough for me.

The question of universals is whether propositions, mathematics, concepts are mind-independently real vs. mind-dependent, and some anti-realists say they are neither: that there is only ever the particular and there is nothing universally common between any two particulars (two men, two oak trees, etc…). It’s not a question of universal statements as I understand you.

I’m genuinely uncertain if they’re as separate as you folk are claiming or if I’m just way off, which is certainly possible. Even probable as my wife might say.

But the opening blurb from the article linked states:

How do we know, for example, that the Pythagorean theorem holds universally , for all possible right triangles?

Using what I said above, we first operate in a reality where true certainty is practically impossible (Gettier Problem).

Next we ask if we or smarter people can find exception and have had ample opportunity to do so.

If so, then whatever it is appears to be a universal. We simply cannot find a single right triangle where pythagoras doesn’t hold.

I’m sure there are subdivisions of the discussion, but I’m not seeing where I’m missing it. Which, again, doesn’t mean I’m not.

Just doesn’t feel like that hard of a concept to me.

Is the pythagorean theorem a mind independent truth of reality that man discovered, or a grammatical, logical truth in a system of contrived, invented axioms by man but which has no objective truth in reality apart from human conventions?

I’ll bite.

It appears to be true even if humans never lived. Wherever a right triangle existed in nature, pythagoras’ theorem would describe the relationship between the hypotenuse and the sides.

For added spice, things like that will probably be the first compared if we encounter an intelligent extra terrestrial species. It would be part of how we would crack each other’s language

I think I might see the issue,

As I’m a fairly “devout” agnostic/secularist/whatever, I just automatically assume that things not rooted in objective reality likely don’t exist universally as part of reality.

Blinders, as it were. Might this be the issue?

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