The debate between scientific realism and anti-realism seems like it’s about theory scope

I’ve been thinking again about the realism vs anti-realism debate, about what scientific theories actually tell us about the world. Historically in the philosophy of science, the debate is between realists, who see scientific theories being at least an approximate representation of reality, and instrumentalists or anti-realists, who see those theories as mere prediction frameworks that predict observations, but can’t really tell us anything more than that.

Most scientists are realists, at least about their own theories. It’s not unusual for people to be realist about some theories and anti-realist about others, depending on how they feel about the implications of the theory. For example, someone can be a realist about germ theory, but an anti-realist toward the quantum wave function.

One thing I’ve been struggling with lately is the binary notion involved here: real vs anti-real. As I’ve noted before, when it comes to something like the wave function, I think some degree of realism is hard to avoid, but that doesn’t necessarily mean accepting full scale realism. This is hard to talk about within a dichotomy between real and anti-real.

It leads me to wonder what the real issue is here. What’s really at stake in these debates? The answer might be the scope of the theory, how broad or narrow its domain of applicability might be. Someone holding an instrumentalist or anti-real stance toward a theory will tend to think its scope is narrow. It works for the observations we’re able to test it against, but they think trying to apply the theory to unobservable outcomes is pushing it beyond its bounds.

At first glance, the anti-real stance seems epistemically responsible. A core tenet of science is testing a model’s predictions. So using the model to say things beyond our ability to test might seem problematic, flirting with the danger of black swans. And yet it’s very common in science to take a well tested model and assume its structure continues beyond what we can observe, to apply it beyond testable boundaries.

For example, geologists use radiometric dating to determine the age of rocks. It’s how we know the age of the Earth, or of fossils. We can test the measurements against things we do know the age of, such as historical artifacts. But for rocks and fossils from hundreds of millions to billions of years ago, we’re assuming that the structures and frameworks we can verify hold well beyond those verifications.

Anyone who’s ever debated a young earth creationist has probably heard the line decrying that this is an overreach of the theory. Do they have a point? A geologist would point out that there were many indications that the earth was far more ancient before radiometric dating came along. There’s also what appears to be corroborating evidence from astronomy and other sources. Although these other sources are also vulnerable to the same charge, that they involve using theories to make predictions far outside of their testable domain.

In short, much of what science tells us about the world gets called into question if we’re consistent in an anti-real stance. Of course, as noted above, most people aren’t consistent with this. The question is how we decide which stance to take for any particular theory. There’s a danger of just choosing based on what threatens or flatters our metaphysical preferences.

Are there more rational justifications for accepting the predictions of theories beyond their testable domain? I alluded to one above, that multiple theories converge and corroborate each other. That seems to increase the probability that they’re accurate in those domains.

Another is to see if there are any indications of the limits of the theory in the data we do have. The classic example is comparing two predictions from Newtonian mechanics, the existence of Neptune outside of Uranus’ orbit, and the existence of Vulcan inside of Mercury’s, in both cases due to issues with the known planet’s orbit. The Neptune prediction was validated a few years after it was made, but the Vulcan one never was, because the limit of Newtonian theory had been reached. General relativity would be required to explain Mercury’s orbital precession.

It’s well recognized that Newtonian dynamics continue to have a very practical domain of applicability. So much so that NASA continues to use it for most of its mission planning. General Relativity is more accurate but much harder to work with. And as someone once pointed out to me, even the ancient geocentric Ptolemaic model retains a domain of applicability for some purposes, such as casual amateur astronomy.

Finding the boundaries of a theory is why I find the experiments testing the limits of quantum superpositions, entanglement, and other aspects of the wave function so interesting. If the real debate is about its scope, then testing its limits will hopefully give us hints on how far we can follow its implications. As noted a few posts back, right now the data doesn’t seem to be giving us any indications of those limits. But of course that could change at any time.

Interestingly, this scoping issue seems to apply to more than just scientific theories, but also philosophical ones as well, but I think I’ll save that for another post.

What do you think? Does thinking about this in terms of scope, of domain of applicability, make more sense than a simply real vs anti-real dichotomy? If not, what do you think the issues are with it?

29 thoughts on “The debate between scientific realism and anti-realism seems like it’s about theory scope

  1. A drive-by shooting… 🙂

    Whether one is a realist or anti-realist, it is hard to argue against the notion phenomenology under-determines ontology. Thus epistemology (necessarily dependent on phenomenology) is an unreliable guide to what there is. Yet over-reach is frequent (e.g. in deriving block universe from Einstein’s strictly instrumental Special Relativity, by eliding SR with Minkowski’s mathematical model of it),

    But I agree that the binary distinction of realism/anti-realism is a mistake. The answer is (1) in coherence of science as a whole (which is, I think is what you are saying) but also (b) in convergence of our descriptions to *something* that actually exists. The tighter the description, the more likely they are to be getting things right (as distinct from being true — a distinction I get from Davidson and Rorty; the trouble-making terms “true” and “truth” ought to be banished from philosophy :-)).

    Two other minor points…

    1. Neptune discovery was no validation of Newtonian mechanics. It was a lucky chance. The derivation assumed Bode’s law of orbits to apply to Neptune and a few decades later would be pointing to a wrong patch of sky as the result. It was just chance that at the time Neptune was in the right place.

    2. The Ptolemaic system in fact amounts to the first two terms of a Fuorier decomposition of Kepler’s orbits and can be made arbitrarily precise by piling on further terms in the form of ever decreasing sub-epicycles.

    Liked by 2 people

    1. Good to hear from you Mike.

      I like the phrase “phenomenology under-determines ontology”. Definitely true. But it seems even worse than that. All observation is theory-laden, so not only does it underdetermine ontology, but phenomenology itself it inescapably contaminated by what we think / hope / expect to be true.

      Einstein was a pretty hard core realist, at least based on the stuff I’ve read about him. I don’t think he’d see special relativity as instrumental. Not that a theory’s author necessarily has the last word on their nature. (Einstein was also notoriously slow to accept some of the implications of his own theories, including Minkowski’s extrapolations.)

      Coherence and convergence with other theories is a good way to put it.

      When it comes to “true” and “truth”, I tend to have a pragmatic attitude. In my mind, the only measure of truth we ever get is predictive accuracy. So when you see me talk about truth, that’s the sense in which I use it. I know a lot of people have a much stricter sense, but as you note, it makes the word useless for philosophical or scientific discussions.

      On Neptune, thanks, I hadn’t heard that. I knew the reality was messier than the quick summaries imply. But rather than the precise prediction on where Neptune was, I was thinking more generally about the prediction that it existed at all.

      Like

      1. Yes, well… Life got a bit complicated. Let’s leave it at that. 🙂 It’ll happen again, I am sure.

        By “convergence” I did not mean convergence with other theories — that comes under coherence of science. (NB I *love* Quine’s slogan that science is like a force field with the boundary condition of experience!) I meant convergence in the sense of progressively tighter description of putative entities. Take the idea of an atom. For ancient Greeks it was merely a device to solve the problem of motion being possible. When chemists got at them much later, atoms were like little balls joint by sticks of valence bonds and one had to apologise for treating them as pseudo-real. Even in Mach’s time it was respectable to doubt their existence, but one had to acknowledge that the notion corresponded to some feature of the world. By the time of the atom as a micro solar system (acknowledged at the time to be wrong, so a mere approximation), their existence was rapidly solidifying, particularly when the nucleus was shown to consist of protons and neutrons, tying that composition back to the periodic table. By the time we have quarks and the vastly complex inner structure of protons and neutrons, it is hard to maintain a disbelief in atoms. The tighter, the more detailed the description confirmed by experiment, the more “real” the described element of reality is. It’s kind of a convergence to some inner core of ontological reality (perhaps just as unreachable as a mathematical limit is in actual practice).

        Was Einstein a realist? I don’t see there being a simple yes/no answer. His 1905 SR paper is explicitly instrumental, and I think he shifted towards realism in working on GR. He certainly never stopped worrying about kinematic versus dynamic underpinning of SR. If you are really interested in this, I strongly recommend Harvey Brown’s “Physical Relativity” for a thorough, philosophical and scientific examination of the alternative, dynamically based view of SR a la Fitzgerald. Personally, I find this small corner of philosophy quite riveting, but that’s an acquired taste. 🙂

        One didn’t need Newtonian mechanics to infer a planet disturbing Uranian orbit. One just had to believe in general applicability of Kepler’s laws and have a general notion that whatever was responsible for binding planets to the Sun, might also work between smaller bodies such as planets. Incidentally, Kepler’s work in coming to his planetary orbit laws is another very interesting story. We do not really appreciate what problems he was facing in trying to account for apparent motion of planets from the PoV of a moving planet, without an understanding of the laws he eventually came up with.

        Like

        1. Totally understand life complications. Been dealing with some of those myself lately.

          Ah, I see what you mean by convergence now. I think it’s important that the convergence happens through necessity, that it’s the data causing the convergence. But definitely the more things are constrained, the more real the resulting concept seems to be.

          From what I’ve read, Einstein was definitely a realist by the time of his debates with Bohr in the 20s and 30s. But it’s possible he was more instrumentalist when he was younger. Some of his later stance might also have come from concern with what quantum mechanics meant for general relativity with the whole “spooky action at a distance” thing.

          Thanks for the Brown recommendation. Hadn’t heard of that book before.

          From what I read about Kepler, his biggest obstacle, probably the biggest obstacles of the time, was in breaking through ancient conceptions of how nature worked. His early attempts to fit the planets into numerological / theological schemes was probably typical for that period. (It’s sobering to remember that people like Kepler were often obliged to do astrological readings for patrons.)

          Like

          1. Einstein was certainly a realist in the sense of believing that the world was quite real and completely independent of our existence — thus his dislike of QM, which appeared to suggest otherwise. That does not conflict with instrumentalism of his SR exposition, whish ditched the realist view of simultaneity and replaced it with a thoroughly instrumental definition of it. That definition was based on the Michelson-Morley experimental results and entailed the impossibility of any kind of information transfer faster than the speed of light.

            Thus SR is not about what there is, but about what can be known. Specifically, it replaces the space-extended “now”, which is no longer knowable, with the whole region of events at space-like separation. It is an unwarranted reification of the Minkowski’s model of the resulting physical relationships, to talk about conflicting “nows” of observers moving at different speeds and to draw any conclusions therefrom. The fact that subsequently time relations of events when they do appear within the past time-cone are to an extent observer-dependent, is no more mysterious than the fact that relative positions in space of visible objects can depend on the observer’s location.

            It is similarly a reification of that model to claim that SR rules out a preferred time frame (and hence a universal, though unobservable “now”). Interestingly enough, I understand that a unique time-foliation appears spontaneously in the Shape Dynamics reformulation (or perhaps extension) of General Relativity. All of which is way above my head mathematically, I hasten to add!

            But I fear I am getting way off-thread. My apologies.

            Like

          2. I’m pretty comfortable with thread drift, so no worries. Although a lot of this is definitely over my head, or at least outside of anything I’ve investigated in depth.

            I do think the fact that SR and GR viewpoints always reconcile with each other is important. Some contemporary physicists try to go places with it, like black hole complementarity, where they don’t, but take refuge in the fact that the participants could never meet to compare notes. To me, once you’re relying on that, you’ve given up either on reality, or at least just one reality. But this isn’t an area I’m super well read in.

            Like

      2. P.S. All observation is theory laden, sure — the Duhem Quine Thesis. But not everybody buys into that. OTOH phenomenology underdetermining ontology is hard to dispute — any disagreement is easily countered by our inability to disprove the “brain in a vat” scenario or any of its equivalents.

        Liked by 1 person

  2. I’m inclined to think that the real vs. anti-real debate is much ado about nothing. It’s an “inside the beltway” argument (the philosophers beltway rather than the politicians).

    In mathematics, I usually say that I’m a fictionalist. But, when actually doing mathematics, I tend to think of numbers as real. It is only when arcane questions (such as the continuum hypothesis) come up, that it becomes important to be a fictionalist (a form of anti-realism).

    I think it’s the same with science. Naive realism mostly works pretty well, and it is only for the sake of a few arcane philosophical questions that one begins to think in terms of anti-realism.

    Liked by 2 people

    1. There is a danger in the real vs anti-real debate in it being nothing but a verbal dispute, about whether the label “real” should be used. That’s one reason I tried to change the focus slightly to the scope of the theory. I think the real reason we disagree about those labels is because we disagree about how far we can follow the consequences of those theories.

      “Fictionalist” is an interesting choice of label. I’ve probably asked this before, but what do you think accounts for the “unreasonable effectiveness” of mathematics?

      Good point that naive realism works most of the time. Once we start making accurate predictions from them, no one really questions whether chemical, biological, or medical theories are real. It’s only when we start looking at theories on the edge of knowability, like with quantum mechanics, that people start asking these questions. Still, I find those questions, and related implications, interesting. I’ve never been able to just take the shut up and calculate stance. (At least other then when I’m just trying to solve some practical question.)

      Liked by 2 people

      1. what do you think accounts for the “unreasonable effectiveness” of mathematics?

        There’s nothing unreasonable about it.

        Science is a systematic study of nature. And mathematics is a theory of systematicity.

        Liked by 1 person

        1. I am with you there. As enthusiasts of the art know, any building can be modelled by gluing matchsticks. This does not mean that there is some profound connection between matchstick gluing and architecture. Similarly, mathematics is a good tool for modelling regularities of the world. Why assume some special connection in this case and not in the case of matchsticks?

          To my mind a *far* more interesting problem is that of the unreasonable effectiveness of statistics. All of statistics is based on the Law of Large Numbers, which in turn is based on independence of events. How is one to justify this independence in the physical world (be it a deterministic or quantomly indeterministic one)? The “it all washes out” argument is itself dependent on the LoLN.

          Liked by 2 people

  3. So. I think some of the realist/antirealist debates are about scope in your sense, and some aren’t. The ones that aren’t tend to start with antirealists saying that all we have are our perceptions and that this (somehow!) prevents us from contacting “reality”. (The latter may be the ones Neil Rickert is calling much ado about nothing?)

    Now at this point you might say “oh, well that’s a merely verbal debate”. But at this point, my evidence suggests that most supposedly “merely verbal” debates actually have substantive issues at their core. The most direct point of conflict may be over some words, but deeper down, different hypotheses (usually with in-principle empirically different implications) are driving the antagonists.

    Liked by 1 person

    1. I guess what I would wonder about concerns on whether theories offer contact with “reality”, is what the substantive issues actually are.

      I’ll definitely acknowledge that people very rarely see themselves as being in a verbal dispute. And it’s probably rare that it’s a pure verbal dispute. It’s just that the real dispute is often thoroughly buried under semantic differences and very hard to suss out until those differences have been resolved.

      Often the appearance of substantive differences hinges on the parties strawmanning each other’s position. Of course, on the flip side, when trying to resolve the definitional issues, we have to be careful not to steelman those positions so much that we’re no longer addressing their real stance.

      Good philosophical discussions are hard.

      Liked by 1 person

      1. Hard, yes. A useful model of semantics in general (disputed and otherwise) is clusters in thing-space. Imagine a high-dimensional space where we map animals by mass, length, volume, running speed, swimming speed, airborne speed, various dimensions of diet, etc. etc. ad nauseam. If we plot all the birds in this space, we see a central cluster where sparrows and crows dwell, and then a few outliers like penguins and ostriches. But even though penguins are oddballs, they still fall “closer” (at least as we humans measure things) to the central birds than, say, monitor lizards do.

        What may look like a semantic dispute – are whales fishes or mammals? – is often a disagreement about where certain items (whales) belong on the high-dimensional map. Hey look! Whales produce milk to feed their babies; they are warm-blooded; they breathe air.

        The linked clusters-in-thing-space article doesn’t talk about causality, but it does mention perceived similarity. And causality matters a lot to the importance of any given dimension to “similarity”. The greater the causal role of, for example, breast-feeding in the development and evolution of animals, the more important this dimension becomes. Opinions about what explains what, causally, are important drivers of people’s inclinations to group things together in different ways.

        Like

        1. The thing space concept reminds me of Wittgenstein’s polythetic definitions, defining things on a broad family resemblance rather than essential properties. I think the idea of these kinds of strategies is important, because it highlights how utilitarian definitions really are.

          The whale example still seems like a semantic issue to me, in how we’re prepared to define “fish”. The reason I would say that is because there’s nothing in nature mandating one answer over the other. It’s all in what we most find productive. We can define fish by shape and function, or by evolutionary lineage. Right now biology focuses on lineage.

          But I take your overall point to be that definitions and categories are substantive issues. I’m onboard with that. It can have a big effect on how we think about things. I’m just not sure what word to use to refer to issues that are more than just semantic.

          Liked by 1 person

          1. I agree also, that there’s nothing in nature mandating that we categorize animals by clades rather than by more superficial features. Unless “nature” includes human nature, and then maybe there is 😉

            Liked by 1 person

  4. Yes Mike, I think I will take your advice and ditch any of my real versus anti-real associations. Thus a theory could be considered in terms of its particular scope or domain of applicability. They’re all simply approximate heuristics anyway. Your advice might help clean up academia — an Occam razor could be used to delete such apparently superfluous conventions. In his latest book McFadden attributes nominalism to Occam just as as much as his famous razor. A quick search gives me this:
    noun
    the doctrine that universals or general ideas are mere names without any corresponding reality, and that only particular objects exist; properties, numbers, and sets are thought of as merely features of the way of considering the things that exist. Important in medieval scholastic thought, nominalism is associated particularly with William of Occam. Often contrasted with realism.

    And indeed, I’d edit the “only particular objects exist” part to the existence of causality itself, if you get my meaning. This is just a name as well of course, but I think a far more representative one.

    In truth there’s only one association that I’ll be giving up here, or “moral anti realism”. I hate how traditional philosophy permits the topic of axiology to begin and end with our various moral notions. But simply aligning myself with existing moral anti realists essentially puts me in the system without demonstrating the scope of what I’d like to change. Beyond our various socially defined notions of rightness and wrongness, I’d like there to be people who consider the nature of the goodness to badness of existing itself. What constitutes this? If a respected community could reach various agreements on the topic, then this should provide a solid platform for scientists to potentially build upon when they attempt to model the nature of beings for which existence can be good/bad (such as the human). And if traditional philosophers can’t bear the thought of agreement in their field, then it seems to me that this needn’t be their field. This new community could instead be referred to as “meta scientists”, and so be responsible for founding science better than it’s founded today.

    Liked by 1 person

    1. Hey Eric,
      Like the razor itself, nominalism doesn’t seem to begin with William of Ockham. But it makes sense that he would have introduced, or reintroduced it into late medieval western thought. Nominalists often say things that make me uneasy, but I sit more easily in that camp than with platonism.

      I’m not a moral realist either, at least not in the sense of thinking moral rules exist as any kinds of laws of nature. But while a lot of philosophers do seem to be moral realists, I don’t perceive it causing issues much outside of moral philosophy. except perhaps in contemplations about consciousness. But then I’m not a realist toward many conceptions of consciousness philosophers are often taken with.

      Liked by 1 person

      1. What would be an example of something that a nominalist might say that you’d be uncomfortable with Mike?

        You say that you’re not a realist towards many conceptions of consciousness that philosophers are often taken with. More explicitly I’m aware that you consider such proposals to subvert causality. Me too, except that I level the same charge against the quite popular “algorithm only” position that you hold. I believe causality mandates that algorithms can only function as such when they animate appropriate substrates. Furthermore the only potential consciousness mechanism that seems both applicable and supported by evidence, appears to be the electromagnetic radiation associated with certain synchronous neuron firing. If experimentally verified in a conclusive enough way, it seems to me that this would become the most transformative evidence that science ever achieves.

        In any case beyond ridding philosophy and science of all manners of non-causal consciousness notions, my point above was that fields which study the function of things for which existence can be good/bad, should not become founded well enough to succeed until after this source of motivation becomes formally acknowledged. It seems to me that even our softest sciences should then develop various basic and yet effective models some day. So I’m far less happy about traditional philosophers monopolizing the topic of good/bad by means of moral notions.

        Liked by 1 person

        1. It seems like many nominalists oversell how unrelated to reality abstract objects are. I don’t think they exist in any platonic sense, but many do represent real patterns in the world. But not all of them. It’s a messy mix, something I think gets overlooked too often.

          Liked by 1 person

          1. So Mike, you’ve come across some extreme anti platonist nominalists? Thus I suppose they’d say that “numbers” don’t exist. Numbers do exist however. They exist as an element of human language. Would numbers exist here without humans? Only in respect to any other creature here which can be said to incorporate such an element of language. Perhaps there are some, though I suspect not.

            Liked by 1 person

  5. The issue, as it seems to me, is not only the limits of scientific explanation, but the question of the extent to which the objects that can be recognized are independent of the way in which man recognizes, or whether the representations of things in consciousness always depend on man’s cognitive capacity.

    The concept of an absolutely objective, observer-independent world in itself is obviously incoherent. In none of our observations is there a criterion by which one could decide whether an observation reflects the world as it exists in itself or not. To do so, one would have to be able to determine, as it were, independently of that observation, what nature is like. The concept of an experientially transcendent physical reality is a tenuous theoretical construct, and so is the ontological separation of the physical world and consciousness.

    However, physics in particular is often regarded as a kind of leading science which allows us an ultimate objective access to nature, independent of any anthropomorphic idiosyncrasies of an observer’s consciousness. It could present nature to us as a closed system, in which not only every event can be causally explained from previous events, but also every event can be traced back to fundamental events which cannot be reduced any further.

    Just modern physics, however, has shown that physical statements can only be justified by recourse to observation procedures, which are connected with concrete ways of experience of the scientist, who would apply a certain measuring procedure. These modes of experience and experience form the basis of our statements about nature. Physical language must always start from experiential distinctions so that we can speak meaningfully about nature.

    So physics and natural sciences in general cannot give a description of an unconscious world in the form of a “view from nowhere”, because science is the practice of a scientist in a scientific community. Thus, the vast majority of scientific facts are charged with theory, since a person or subject must be familiar with the basic assumptions and concepts of a scientific theory of a research program in order to be able to state those facts, which must always be seen in the context of particular scientific theories. Objective observational facts are generally not even sufficient to falsify these theories; in fact, there is always the possibility that, independent of the theory in question, a hitherto unobserved background assumption or an unobserved partial aspect of a complex test situation could explain all seemingly contradictory observations without contradiction.

    Liked by 1 person

    1. I’ve never read anyone who claimed that absolute objectivity is possible (at least not anyone thoughtful). Everyone admits that there is no view from nowhere. But that doesn’t mean it’s all equally subjective. Impressions from a single view are subjective relative to whoever (or whatever) that observer is, and is limited by that observer’s blind spots and limitations.

      “Objective” in thoughtful discourse is, I think, only meant to describe models developed from numerous viewpoints. The larger the number (and the more informed) the better in compensating for those blind spots, biases, and other limitations. Of course, compensating for individual limitations is easiest. Compensating for cultural or special level biases and blind spots is much harder. And there’s no guarantee we succeed at it.

      Still, the knowledge gained from numerous viewpoints is historically much more reliable than knowledge gained from one or a few viewpoints. Nothing is ever perfect.

      But certainly if we ever encounter aliens, we’ll likely be shocked by how different their view of the world is.

      Like

  6. Mike writes…

    “One thing I’ve been struggling with lately is the binary notion involved here: real vs anti-real. ”

    I can’t usefully speak to much of what is being discussed here, but the sentence quoted above could be a doorway in to another important topic.

    All of science is made of thought. The scientists too. Thus, it seems important to investigate the properties of the medium of thought to better understand any bias it may be imposing upon all of it’s creations.

    Thought operates by dividing the single unified reality in to conceptual parts. Thus, binary notions abound in every direction. This pattern of division is a form of distortion imposed on everything thought touches.

    Is this post good, or is it bad? Is it right, or is it wrong? Is it on topic, or off topic? The endless quest for thought generated binary notions could be obscuring the fact that this post is most likely all of the above.

    Liked by 1 person

    1. I definitely think we should approach binary distinctions with caution. Usually it’s a simplification of the referred reality. Is something a hill or a mountain? If it life or non-life, male or female, mammal or non-mammal, conscious or non-conscious? For each of these, there seem to be cases along the borders where we could argue about which side they fall on.

      But in nature these entities just are, and don’t care about our little categories. Pluto is Pluto regardless of whether we label it a planet or something else.

      In terms of thought, my thinking (hah!) is that we should always be prepared to look at things from multiple perspectives and frames, to put on different filters. Often when we do that, we discover that some categories, while useful in colloquial conversation, aren’t well defined and probably aren’t productive for scientific investigation. In other cases, different concepts might actually map to the same concept once we clear all the semantic issues.

      But thinking about thinking is at the heart of philosophy, so definitely it’s an area we should always pay attention to.

      Like

Your thoughts?

This site uses Akismet to reduce spam. Learn how your comment data is processed.