Is nominalism generally considered to be disconfirmed?

Question

In Are numbers particulars?, David Gudeman states "nominalist, which I don't think anyone is these days." I was not aware that nominalism regarding universal is generally considered to be disconfirmed and is by most excepted as false. If yes, which argument has been so compelling? I am particular (no pun intended) surprised of this statement, as hardcore materialism is relatively common among people I know (not necessarily philosophers) and accepting universals to be true is not very materialistic in my opinion.

Answer 1

There's consistently been an even amount of platonists & nominalists and this continues to be the case in contemporary philosophy, see the PhilPapers survey (actually, right now, there might be marginally more nominalists).

When platonism is contrasted exclusively with nominalism, this is about abstract objects and not properties (though transcendental universals are just one kind of abstract object that, if they exist, would also entail abstracta platonism): it is important to distinguish between the debate about the ontology of properties where platonism, immanentism, conceptualism, etc battle it out versus the debate about the existence of abstracta where it's just platonism (they exist), nominalism (they don't). Candidate abstracta may be platonic properties, sets, propositions, numbers, geometric shapes, etc. An example is that Quine was a nominalist in the former sense but a platonist in the latter sense.

Some of the arguments for abstracta platonism come from mathematical platonism, scientific realism & indispensability arguments, and meaning.

Answer 2

I see the surveys showing no drop in support for nominalism among philosophers in general, and agree that may be the case among your materialist colleagues as well. But that does not appear to be the case among the theorists of materialism/physicalism.

I reference four good theoretical discussions from this century: the Rise of Physicalism by David Papineau, Physicalism by Daniel Stoljar, A Physicalist Manifesto by Andrew Melnyk, and Physicalism or Something Near Enough by Jaegwon Kim. All are physicalists or physicalist-leaning "near" physicalists.

Three of the four explicitly state that physicalism no longer is a monistic ontology. The possibility of non-physical objects or items in our world is compatible with physicalism, per those three authors. They do not even assert that non-physical things are causally inert, only that they do not act as causes in physics. The fourth, Kim, agrees that non-physical things exist, but holds that they are causally inert. Kim is the only one of the four who holds that physicalism is a monism, and our world NOT being monistic is why he is now only "near" physicalism.

Stoljar, the other "near" physicalist, was even willing to accept non-monistic physicalism. He only abandoned it because of Hempel's dilemma, which did not allow for the even minimal criteria of causal inertness for the non-physical. If one cannot define the physical vs non-physical, then causal inertness for the non-physical is not a claim with any content, so it cannot be the defining criteria of physicalism.

Stoljar, despite being an almost physicalist, actually has a very negative view of the REASON for physicalism's popularity. He considers the philosopher's role to be being displaced by science, math theory, and linguistic theory, such that philosophers are a bit at loose ends for what to do. But physicalism offers a ready made role -- explain to the public why when the world APPEARS to not be purely physical, it really IS. Note, this role is the same as that assigned to the branch of Apologism in theology. Philosophers as apologists for an ideology -- is not a very positive view of philosophers.

As an empiricist, who accepts indirect realism as the way to infer what is real, I have always been a bit mystified by nominalism. Math, abstractions, and experiences, are all as reasonably inferred to be real as matter. How nominalists propose to do epistemology, how do they know that abstractions are not real, I have never seen spelled out. Nor has it been at all clear to me what a "nominal" IS. Sure, it is a thought problem, created by a mind, to do a purpose. But none of that (thought, problem, mind, purpose) seem to be material, so how this explanation makes nominalism monistically material remained a mystery to me. This identical process is also how Popper's triplest ontology would describe model making, so I did not see how this description avoided ontic triplism.

Stoljar's explanation of apologism as a philosophic project, strikes me as particularly relevant to nominalism. Nominalism appears to me to mostly be a word salad designed to try to obscure the ontic nature of the emergence process that it is describing.

Plus nominalism cannot explain why theoretical physicists mostly treat math as more fundamental than matter. If matter reduces to the symmetry principles and probabilities and waveforms of the Standard Model, then math, and abstraction, is not "nominal" at all, but is more "real" than anything else.

The widespread abandonment of reductionism and its replacement by pluralist emergence among philosophers of science in this century, strikes me as removing both the plausibility of and need for a nominalist description of abstractions. Non-reductive physicalism basically admits to an ontically non-physical mind being emergent from matter, then ideas being emergent from mind. And non-reductive physicalism is the vastly most widespread view of physicalism among philosophers of mind.

I believe the theoreticians of physicalism have understood these challenges to physicalism that make physicalism no longer plausibly a monism, and that the unclear rationale for the "nominality" of ideas is no longer a useful bit of apologetics, hence none of the contemporary physicalist theoreticians are still arguing for nominalism. There is a lag between the theoreticians of a movement, and its adherents, which is why I think the survey is lagging the theorists.

If mine is an invalid understanding of the issue, I hope a better answer is posted here.

For interest, here are my reviews of Stoljar, Melnyck, and Kim. https://www.amazon.com/gp/customer-reviews/R1A8I0RTYJEDJM/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=0521038944 https://www.amazon.com/gp/customer-reviews/R13R2OUNXMIN6H/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=0415452635 https://www.amazon.com/gp/customer-reviews/R1LFTMUSP8VEWB/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=0691133859