One wishes for an intellectual solvent that will dissolve what is false but leave the truth intact. Many see science as such a solvent, and it is, at least for some specific questions. But if one broadens the perspective to big questions of ultimate meaning, one runs into the universal solvent conundrum -- a universal solvent dissolves anything, but what container can hold it? A universal intellectual solvent dissolves truth as well as error.
Relating science and religion, nontheistic religious naturalism seeks natural explanations for religious practices and beliefs that dissolve the substance of traditional theology. Advocates often talk about the primacy of science and reason. But can they apply their solvent to their own efforts?
Philosophy deals with similar questions, considering realism and alternatives to it. The nature of people and things is a perennial question, and modern science grew on assumptions of objective realism. But from the time of Plato it was recognized that things may not be as they seem, and what we see may be mere shadows of the real forms of things. Modern science discovered many previously invisible things, and doubts about the reality of molecules and atoms faded. But there were growing problems with straightforward realism in general relativity and quantum mechanics.
Is there a viable alternative to realism? I myself don't think so, but I do want to understand those who do, and I know there are such people, staunch proponents of science and reason who nevertheless disavow the reality of concepts. I want to test my understanding by using an imaginary dialog between two avatars, putting forth and countering arguments for and against. My avatar for realism I call Ray, straightforward as a ray of light, and the avatar against I call Nom, from nominalism as an alternative way to see the world.
Ray: I understand you've heard my "intellectual solvent" argument against nominalism, but you think I've misunderstood your view of science and reason. Where have I gone wrong?
Nom: You say my nominalism is effectively a universal solvent that dissolves its own basis and so is inconsistent and false, irrational nonsense. But you can only make this claim by extending what I say beyond its proper context. You twist my story of how human nature and reason emerges from nothing but matter in motion, so you argue that what I say is empty talk, just so much hot air. Your wrong twist is to take what I say too broadly, applying "nothing but" to the story itself, not just to the physical substrate as I intend.
Ray: So you do believe in the reality of matter in motion? I won't try to nit-pick the "matter in motion" phrase since it seems like a nice way to refer to physicalism or naturalism. Do we agree that there is an objectively real physical substrate to things?
Nom: I suspect you're trying to trap me with this talk of objective reality, so I do want to point out that "objective reality" is an abstract concept. Don't mistake me for some nihilist or silly solipsist who thinks it's all in my head. I can say the physical world is objectively real, with an implicit asterisk to indicate that "objectively real" is a phrase that is easily misunderstood. It a phrase of natural human language, only meaningful to the degree we mutually find it so. Our understanding of it is nominal, and you spoil the game when you try to take an objective stance toward our understanding itself.
Ray: Ah, so you say that our understanding is not objectively real?
Nom: It's as real as understanding can be, given that understanding is something embodied in our selves. And we have to remember that our "self" is a complex social construct that emerges from our physical nature.
Ray: So you say that the physical world and its particular parts really exist, but that abstract concepts or universal properties do not. These have no reality beyond our naming of them, is that what you mean by nominal?
Nom: Yes, that's a nice summary in everyday English of my worldview, but I do want to call attention to the extensive philosophical literature on nominalism and realism, where terms like "exist" and "universals" have well-developed meanings beyond what we can consider in our dialog today. I hope you won't take a simplistic approach that ignores all this.
Ray: Let me assure you that I've tried to make sense of some of this literature, and my sense of it is that it begs the question of its own meaningfulness in the way that my solvent argument highlights. It starts with our scientific understanding of nature to claim that the physical world is the primary reality and our understanding of it is a secondary, emergent feature with no reality itself. This is circular reasoning.
Nom: No, it's you who fall into the fallacy of circular reasoning by assuming there's a way to talk about this issue that is outside the issue itself. All our talk of this depends on natural human language, and while we can talk of abstract things like logical propositions which may collapse into circular reasoning if we're not careful, we have to remember that logic and reason are human constructions.
Ray: So logic and reason, truth and falsehood, are socially constructed and have no reality in themselves?
Nom: I know where you're going with this line of argument, and I don't like it.
Ray: You know the academic understanding of bullshit is talking as though truth doesn't exist, an idea associated with an essay by philosopher Harry G. Frankfurt. So do you agree that nominalism is bullshit?
Nom: Of course not, and you should be ashamed to even suggest it, given all the respected philosophers and scientists who support nominalism.
Ray: I'm emboldened in being direct even if crude by one of my heroes, Martin Luther, of whom Thomas Cahill says " ... Brother Martin -- this 'pile of shit,' as he so often called himself -- dared to say 'No' to the assembled forces of early modern Europe, ... ". So I'll stand firm, and say again that you're talking crap if you think truth doesn't exist.
Nom: Truth exists, but not in the general, abstract, global way you insist on. You're just thinking of the old naive correspondence theory of truth, haven't you heard of the newer semantic theory of truth? It's associated with the philosopher Alfred Tarski, and says truth is basically a disquotation operator, as in "snow is white" is true if and only if snow is white.
Ray: Tarski's work was on formal languages where statements in an "object language" can be talked about in a "metalanguage", and efforts to extend his ideas to natural languages which are self-contained have been criticized as circular. The problem seems to be with self-reference.
Nom: Yes, and this issue has been thoroughly explored by Douglas Hofstadter is his book I Am a Strange Loop. He seems happy with being an emergent epiphenomenon, and you should be too.
Ray: I am happy with this story as far as it goes. Human nature is embedded in the natural world, and our language is socially constructed. Maybe as a linguistic theory nominalism is fine, but not as a theory of what we can know and how we can know it. It's only when nominalism purports to be an ultimate worldview that it dissolves into foolish nonsense.
Nom: I didn't say nominalism is the ultimate worldview. I talk more modestly about non-theistic naturalism.
Ray: I appreciate this distinction, since it implies there is a naturalism that is not non-theistic. You know I hold such views, sometimes called panentheism. So I can be a realist about things like the natural numbers and geometric shapes, while recognizing that our talk of them is nominal. So do you think the natural numbers are real?
Nom: That's a trick question, and you know it. It depends on what we mean by "natural number" and "real", and how the meaning of "natural number" relates to the meaning of "natural" and "number". In mathematics, "natural number" and "real number" are carefully defined terms, and the natural numbers are a subset of the real numbers, so I have to agree that the natural numbers are real when we're talking math. But this is nominal, the way we agree to talk in this context.
Ray: So numbers like 1, 2, 3, and so on didn't exist before there were people to talk about them?
Nom: Not as we think of them, as abstract concepts. It depends what we mean by "exist".
Ray: You're full of talk of meanings, yet you say meanings are only nominal. I agree that "number" and "exist" are words of the English language and of course others may talk differently. But doesn't it seem strange to you to say that the numbers don't really exist?
Nom: What's so essential about numbers being real? Mathematics was developed by people, don't you agree that numbers are part of math?
Ray: If you mean that numbers were created by people, no. People developing math discovered numbers, they didn't just invent them. This is the case not just with the natural numbers like 1, 2, 3, and so on, but also with what mathematicians call, suggestively, the "real" numbers, which include irrational numbers like the square root of 2. There were doubters early on, but that faded as math developed and it proved impractical to build an equivalent system without accepting irrationals.
Nom: So you say the real numbers are real, but do you think the irrational numbers are irrational? You realists are prone to fall into the trap of literalism.
Ray: Overly literal readings can be corrected, and tend to bring up issues which can be investigated by science. Your nominalism dissolves any issues in its path before they even arise, so instead of being scientifically fruitful it is hopelessly sterile.
Nom: Whoa there! That's wrong, and one insult too many for me today. I think it's time to wrap up this dialog and hope that some of my friends can enlighten you before we meet again.
Like my imaginary avatars Ray and Nom, I’ll leave it there for now.
Daniel Johnson
2014-Oct-06, updated 2015-Aug-25
Houston, TX