Progress in Philosophy — III

philosophy[for a brief explanation of this ongoing series, as well as a full table of contents, go here]

Philosophy of science: forms of realism and antirealism

I’m a philosopher of science, and therefore better acquainted with that subfield than with anything else in philosophy. And it is clear to me that philosophy of science has also made quite a bit of progress from its inception (the approximate time of which may reasonably be pegged onto the famous debate on the nature of induction between John Stuart Mill and William Whewell, but which could be traced further back at the least to Bacon). In this section I will go over a specific example (among many, really) of progress in philosophy of science, the debate between realists and antirealists about scientific theories and unobservable entities (interested readers should also see the many useful references listed in the pertinent SEP entries: Monton and Mohler 2008; Ladyman 2009; Chakravartty 2011).

To begin with, let us be clear about what sort of debate this is: it concerns what our best epistemic attitude should be toward scientific theories, as well as toward the “unobservable” entities posed by most of these theories, such as electrons, strings and so forth. The broad contrast is between realist and antirealist positions, though each one comes in a variety of flavors and nuances. Within the context of this discussion, “observable” means by way of normal human sensorial experience (as opposed to scientifically observable): stars and dinosaur bones are observable; electrons and galaxies are not, in this sense. While the distinction so drawn is obviously arbitrary, since it is defined by the sort of human sensorial access to the world, that is precisely the point: the realist-antirealist discussion is one that concerns human epistemic limits within the context of science, as well as the degree to which our ontology should be justified by our epistemology.

Scientific realism comes with a number of commitments: epistemically, it takes scientific theories to yield knowledge about the world — as opposed to a more limited instrumentalist interpretation of those theories, which at most grants that we can have knowledge of observables, but not of unobservables. Metaphysically, for a scientific realist the world exists independently of human minds, a stance which is of course open to the Kantian objection that we do not have access to the world-in-itself, only to decidedly not mind-independent experiences. Semantically, scientific theories are to be taken at face value for the realist, as statements about the way the world is — as opposed to, again, instrumentally (i.e., they just work, in a pragmatic sense). Of course realists do typically admit that most scientific theories are, strictly speaking, false, which is why they often appeal to the notion of “truth-likeness,” rather than truth (see Chapter 4). As a result of this, realists tend to be fallibilists about scientific knowledge but nonetheless maintain that science makes progress by getting incrementally — though not necessarily linearly, or even always monotonically — closer to a true description of the world.

There are at the least three major varieties of realism, which are committed to stronger or weaker versions of the above. Entity realism holds that we have good reasons to be realists about any entity described by a scientific theory of which we have successful causal knowledge (e.g., black holes in cosmology); explanationism is the idea that we should be committed to realism with respect to the “best,” most indispensable, parts of scientific theories (e.g., quarks in fundamental physics); and structural realism is the position that we should be realist not about the entities invoked by scientific theories, but about the (mathematical) structure of those theories (e.g., treating the equations of Newtonian mechanics as a limit case of those from Special Relativity).

There are a number of arguments in favor of and against scientific realism, and the field has made progress precisely insofar these arguments have been presented, criticized, modified, further criticized, refined, and so forth, the by now familiar exploration by move and counter-move of philosophy’s conceptual spaces. Briefly, there are three major reasons typically deployed in favor of scientific realism, the best known of which is Putnam’s (1975, 73) “no miracles” argument: “[realism] is the only philosophy that doesn’t make the success of science a miracle.” To this, van Fraassen (1980) — a major critic of realism — responded that a different way of thinking about the issue is to consider good scientific theories as the conceptual equivalents of successful living organisms: adapted to their environment and therefore effective. That, in turn, raises the issue of what, exactly, accounts for the adaptness of a scientific theory, not an easy issue to address, given that we still lack a satisfying explanation of cultural evolution couched in selective terms (though plenty of people have been working on it). Another objection raised against the no miracles argument is constructed on a version of the base rate fallacy: we just don’t know what the baseline expectation for successful scientific theories is (i.e., we do not have an independent control against which to make assertions of success or failure), so on what grounds are we surprised by the effectiveness of science? I confess that I find this objection formally intriguing, but ultimately bizarre, unless one wishes to deny the truly astounding degree to which science has made progress compared to any other way that human beings have devised to learn things about the natural world.

The second standard argument in favor of realism is corroboration, the idea that if different means of empirical detection, or different theoretical approaches, converge on the same conclusions then we have good reasons to be realists about those conclusions, a meta-theoretical version of Whewell’s (1847) famous consilience of induction. For instance, Ladyman and Ross (2009) have argued that there are several theoretical invariants in fundamental physics, regardless of which of a number of currently competing theories about the basic structure of reality turns out to be true. It seems sensible, therefore, to suggest that those theoretical invariants will survive independently of which of the competing theories will eventually be settled on by fundamental physicists (this is a type of structural realism).

Finally, we have selective optimism, the suggestion that we can retain entities or theoretical structures from previous theories, if they keep playing a successful role in new theories, which in turn gives us reasons to be realists about those entities or structures. In the case of entities, Ladyman (2009) suggests that this nicely dovetails with the kind of theories of reference proposed by Putnam (1975) and Kripke (1980), which maintain that one may retain successful reference to certain entities (e.g., electrons) even in spite of substantial background theoretical changes, leading to a certain stability of epistemic commitments even in the face of theory change.

On the other side of the debate, there are well articulated (and just as carefully criticized) arguments against scientific realism. Perhaps the best known is the problem posed by the underdetermination of theory by data, which is closely related to the Duhem-Quine theses (Chapter 2). The idea is that there are always, in principle, many different theories that are equally compatible with the data, or — equivalently — that the available data is not enough to determine the truth of a theory and the falsity of closely related theoretical variants. The problem with this objection is that it is actually difficult to find historical examples of rampant underdetermination, or of an underdetermination that was not soon resolved. Then again, perhaps the best current example of massive underdetermination of theory by the data is string/M-theory in fundamental physics (Woit 2006; Smolin 2007; Baggott 2013), with its “landscape” of 10^500 (give or take) possible versions and essentially no empirical evidence to even tell us whether the broad outline of the story is correct.

A second standard objection to scientific realism is rooted in skepticism concerning the  idea of the above mentioned inference to the best explanation (IBE), which can be articulated on two levels. First, there is criticism of the very concept of IBE, based on the difficulty to make explicit what criteria are to be deployed in order to determine that a given explanation is, indeed, “the best.” Should we use simplicity? Elegance? A combination of these, and what else? The matter is actually not at all trivial, though my sense is that most philosophers do think that IBE is a defensible type of inductive inference. Second, van Fraassen (1989) noted that at any given point in time in the history of science we may just have a “best of a bad lot” situation, so that even if we had a principled way to make an inference to the “best” (available) explanation, we would have no reassurance that such explanation was even in the ballpark of the true one.

Then we have the problem (for realists) posed by the so-called pessimistic meta-induction: Laudan (1981b) pointed out that the history of science provides us with a number of examples of theories that were thought to be correct and were eventually rejected. Thus, by standard inductive generalization one would be justified in concluding that current theories will also, eventually, turn out to be false. If there is no principled way to address this, then an epistemically modest attitude toward scientific theorizing — such as antirealism — seems warranted. The pessimistic meta-induction can be countered by deploying the notion of truth-likeness, the idea that we are getting incrementally closer to the truth in a way that can be argued without falling into question begging, and which I have already discussed in Chapter 4. Needless to say, antirealists have also criticized the very notion of truth-likeness.

So much for the basic version of scientific realism and its main flavors. Let me turn now to a symmetric treatment of the major alternative proposal, van Fraassen’s constructive empiricism. The opening salvo for a renewed attack on scientific realism was his The Scientific Image (1980, 12), at the onset of which he unequivocally threw the gauntlet down: “Science aims to give us theories which are empirically adequate; and acceptance of a theory involves as belief only that it is empirically adequate.” It is this book that is usually credited with the rehabilitation of the very idea of scientific antirealism, after the demise of logical positivism (Stadler 2012).

Constructive empiricism has much in common with logical positivism, particularly the commitment to purge what are perceived as unnecessary metaphysical burdens from our view of science; however, van Fraassen’s position — unlike logical positivism — does not rely on the (in)famous verification principle, nor does it shy away from the idea that scientific discourse is necessarily theory-laden. The crucial notion is that of empirical adequacy, which van Fraassen characterizes in this manner: “a theory is empirically adequate exactly if what it says about the observable things and events in the world is true — exactly if it ‘saves the phenomena’” (1980, 12). But constructive empiricism advances a number of additional ancillary notions, a particularly important one being the distinction between observables and unobservables, where the line separating the two categories of facts or entities is understood as relative to human beings qua epistemic agents.

As in the case of scientific realism, over time several arguments have been put forth in favor of constructive empiricism, and naturally many such arguments mirror the ones we have seen above about realism. We do not therefore need to revisit the idea of underdetermination of theory by data, or the pessimistic meta-induction. Beyond those, a major point highlighted by van Fraassen is that his preferred criterion of empirical adequacy is epistemically more modest — so to speak — than claims of truth, while still making sense of science as an epistemically successful activity. Another major difference between constructive empiricism and scientific realism is the way these two frameworks approach the proper relation between theory and experiment: realists think that experiments teach us about observables as well as unobservables, while constructive empiricists think that experiments only teach us about the former.

Pragmatism is big among constructive empiricists. They, for instance, follow a pragmatic approach to theory choice: van Fraassen rather astutely observes that scientists themselves often deploy criteria for theory selection that are not strictly epistemic, but — in fact — pragmatic, for instance, when a theory is preferred over another on grounds of simplicity, elegance, etc. He also advances a pragmatic view of explanation, providing a long list of past scientific theories that had explanatory power and yet turned out not to be true (this is conceptually distinct from the point about the pessimistic meta-induction): e.g., Newton’s theory of gravitation explained the movements of the planets, and Bohr’s theory explained the spectrum emitted by hydrogen atoms. It seems uncontroversial that scientific explanations do include a pragmatic component, but — adds the constructive empiricist — how can the scientific realist insist that they are good explanations because they are true statements about the world, given examples such as these and a number of others that can easily be gleaned from the history of science?

Indeed, van Fraassen’s pragmatism even extends to the very idea of laws of nature, which he regards as unnecessary metaphysical commitments, in explanatory terms, to which nonetheless the scientific realist seems wedded. Constructive empiricists point out that natural laws are actually only true on a ceteris paribus clause (a point famously also made by Nancy Cartwright: 1983), that is, they depend crucially on counterfactuals that are — strictly speaking — empirically inaccessible. Both the emphasis on empirical adequacy and the frontal assault on the sacred cow of natural laws is part and parcel of one of the major points in favor of constructive empiricism, according to its supporters: a philosophical program that puts a stop to “inflationary metaphysics.” As van Fraassen (1980, 69) clearly explains: “the assertion of empirical adequacy is a great deal weaker than the assertion of truth, and the restraint to acceptance delivers us from metaphysics.” The idea is that the constructive empiricist can drop concepts such as those of laws of nature, natural kinds and the like, without any apparent loss in explanatory adequacy.

As in the case of scientific realism, there are a series of moves in conceptual space that various authors have made to dispute constructive empiricism — with the full ensemble of these moves and countermoves representing another instance of what I call progress in philosophy. We have already encountered some of these maneuvers, beginning with Hilary Putnam’s no-miracles argument, and with the scientific realist’s invocation of inference to the best explanation.

A less successful charge against constructive empiricism was led by Paul Churchland (1985), and it fundamentally hinged on the arbitrariness of the observable / unobservable divide drawn by van Fraassen. While prima facie reasonable, Churchland’s objection actually misses van Fraassen’s point: as explained above, the latter was not attempting to draw a hard metaphysical line between observable and unobservable, but simply making the more mundane empiricist observation that scientific knowledge is human knowledge, and therefore bounded by the limits of humans qua epistemic agents, including the by no means arcane fact that we can observe certain things and not others.

Be that as it may, a recent survey of philosophers’ positions (Bourget and Chalmers 2013) clearly gives realism the upper hand over anti-realism (75% vs 12%, give or take — see next Chapter for more details), though the survey itself does not discriminate among types of realism and anti-realism. One of the factors contributing to this disparity may be the next big leap in the exploration of the realism-antirealism conceptual space, to which I now turn: structural realism (Ladyman 2009), a conception first introduced by John Worrall in 1989, a few years after van Fraassen’s book.

Again recall that one of the most convincing grounds in favor of realism is Putnam’s no-miracles argument, and one of the strongest rebuttals by antirealists relies on some version of the pessimistic meta-induction, or at the least on the observation that major scientific theories of the past have been abandoned (something often referred to as “radical theory change”). It was therefore perhaps inevitable that the following major counter-move by realists is a novel type of challenge to the idea of radical theory change. Here is how Worrall (1989, 117) himself put it, in the case of a specific historical instance: “There was an important element of continuity in the shift from Fresnel to Maxwell — and this was much more than a simple question of carrying over the successful empirical content into the new theory. At the same time it was rather less than a carrying over of the full theoretical content or full theoretical mechanisms (even in ‘approximate’ form) … There was continuity or accumulation in the shift, but the continuity is one of form or structure, not of content.” That is, the commitment by the realist should be to the mathematical or structural content of scientific theories — what, allegedly, gets conserved across theory change — rather than to specific unobservable entities or descriptions of those entities.

From a historical perspective, there are indeed a number of apparent cases of successful structural transition between scientific theories, besides Fresnel => Maxwell. For instance, Saunders (1993) has argued that there are surprising structural similarities between Ptolemaic and Copernican astronomy, as counterintuitive as that may seem. More convincingly, perhaps, Bohr famously argued that classical models in physics are a limit case of quantum mechanical ones, and the same is true of the relationship between classical mechanics and Special Relativity.

It is important to distinguish between two major varieties of structural realism, epistemic and ontic, each representing — in the model of progress in philosophy that we are exploring — a distinct local peak in the conceptual mountain range that defines the realism-antirealism debate. In the case of epistemic structural realism, the idea is that one is justified in being a realist about the relations between unobservables, while remaining agnostic as to their ontological status. Intellectual forerunners of this approach date back at the least to the beginning of the 20th century (e.g., Poincaré), and can be read according to a Kantian key: science gives us access to the structure of the noumenal world, but not to its substance. More recently, Maxwell (1972) has defended a modern interpretation of epistemic structural realism deploying the concept of Ramsey sentences (Papineau 2010; Frigg and Votsis 2011) and turning it into a semantic theory. However, Ladyman (1998) has argued that this doesn’t actually constitute much of an improvement over standard structural realism, and that a stronger, metaphysical (rather than just epistemological) move is necessary.

Which brings us to the ontic approach. As Worrall phrased it (1989, 57): “[O]ur science comes closest to comprehending ‘the real,’ not in its account of ‘substances’ and their kinds, but in its account of the ‘forms’ which phenomena ‘imitate’ (for ‘forms’ read ‘theoretical structures,’ for ‘imitate,’ ‘are represented by’).” The focus, in other words, is on the structure of the relations among things, not on the things themselves — hence the title of Ladyman and Ross’(2009) book, Every Thing Must Go. Indeed, ontic structural realism can be seen as a “naturalized metaphysics” based on the most current accounts of the fundamental nature of the world provided by physical theories where, because of phenomena such as quantum non-locality and entanglement, the deeper one digs the less one finds anything like physical objects at the bottom of it all.

There are, predictably, a number of objections that have been moved to ontic structural realism, a fundamental one being that it endorses a strange metaphysics where there are relations without corresponding relata, which strikes many commentators as being this (visualize a very very short distance between your index finger and thumb) close to absurdity. I do not wish to get into the details of this sort of discussion here, though the various criticisms and counter-criticism of ontic structural realism represent a micro-cosmic version of my general thesis about movement in philosophical conceptual space. Ladyman (2009) lists and discusses seven different ways available to supporters of ontic structural realism to respond to the relations-relata problem, ranging from biting the bullet and going Platonic, so to speak, to the idea that individual objects do not have intrinsic natures after all, to a rejection of Humean-type supervenience, just to mention a few. Regardless, and as I’ve stated above, a major point in favor of ontic structural realism is that it is consistent with — indeed it is partly inspired by — the view of reality that originates from current fundamental physics. In particular, physicists nowadays think in terms of fields, rather than particles, since particles, in a quantum mechanical sense, don’t really exist as individual entities and are better thought of as field attributes of space-time points, which sounds a lot like there are no “things” or relata, just relations.

Irrespective of the debate about relations sans relata, there are several other objections to ontic structural realism: without going too deep (see review by Ladyman 2009), Chakravartty (2004) is among those that argue that sometimes structure too is lost during theory change, resulting in so-called Kuhn-losses (Post 1971, Chapter 4). Another issue is that ontic structural realism essentially turns metaphysics into epistemology (which may or may not be a good thing in and of itself, depending on one’s philosophical leanings), because it defers too much to the results of the natural sciences (especially, or, rather, pretty much exclusively, fundamental physics). And the proper relationship between metaphysics and epistemology is, naturally, a whole separate area for discussion (Chalmers et al. 2009; Ross et al. 2013). Moreover, some critics (e.g., Chakravartty 2003) argue that ontic structural realism cannot account for causality, which notoriously plays little or no role in fundamental physics, and yet is crucial in every other science. For supporters like Ladyman causality is a concept pragmatically deployed by the “special” sciences (i.e., everything but fundamental physics), yet not ontologically fundamental.

A more serious objection, I think, is that even modern physics still lacks a way to “recover” macroscopic individuality from quantum non-locality (after all you and I are individuals in a rather strong sense of the term, unlike tangled electrons). Without this account, both fundamental physics and ontic structural realism look significantly limited. Related to this is the even broader point that structural realism essentially applies only to (again, fundamental) physics. There has been little or no effort to unpack the notion of theoretical structural conservatism in other areas of physics, let alone in any of the special sciences, for instance evolutionary biology. The fact that often enough theories in these other sciences don’t look particularly mathematical may be imputed to the relatively early stages of developments of those disciplines, but it may also represent a core limitation of a physics-centric way of looking at science as a whole. Finally, and this is to me a fascinating metaphysical point in itself, ontic structural realism basically collapses the distinction between the mathematical and the physical. Some mathematical physicists, like Max Tegmark (2014) have boldly gone down that route, talking about an essentially mathematical universe. As much as this sort of stuff is fun to think about, it does seem at the least problematic to make sense of the notion that mathematical structures are “real” in an even more fundamental way than physical entities themselves. And so the exploration of the pertinent conceptual landscape continues.


Baggott, J. (2013) Farewell to Reality: How Modern Physics Has Betrayed the Search for Scientific Truth. Pegasus.

Bourget, D. and Chalmers, D.J. (2013) What do philosophers believe? Philosophical Studies 3:1-36.

Cartwright, N. (1983) How the Laws of Physics Lie. Oxford University Press.

Chakravartty, A. (2003) The Structuralist Conception of Objects. Philosophy of Science 70:867–878.

Chakravartty, A. (2004) Structuralism as a Form of Scientific Realism. International Studies in Philosophy of Science 18:151–171.

Chakravartty, A. (2011) Scientific Realism. Stanford Encyclopedia of Philosophy (accessed on 26 June 2012).

Chalmers, D., Manley, D. and Wassermann, R. (eds.) (2009) Metametaphysics: New Essays on the Foundations of Ontology. Oxford University Press.

Churchland, P. (1985) The ontological status of observables: in praise of the superempirical virtues.” In: P. Churchland and C. Hooker (eds.), Images of Science: Essays on Realism and Empiricism, University of Chicago Press, pp. 35–47.

Frigg, R. and Votsis, I. (2011) Everything you always wanted to know about structural realism but were afraid to ask. European Journal for Philosophy of Science 1:227-276.

Kripke, S.A. (1980) Naming and Necessity. Blackwell.

Ladyman, J. (1998) What is structural realism? Studies in History and Philosophy of Science 29:409–424.

Ladyman, J. (2009) Structural Realism. Stanford Encyclopedia of Philosophy (accessed on 16 August 2012).

Ladyman, J. and Ross, D. (2009) Every Thing Must Go: Metaphysics Naturalized. Oxford University Press.

Laudan, L. (1981b) A Confutation of Convergent Realism. Philosophy of Science 48:19–48.

Maxwell, G. (1972) Scientific methodology and the causal theory of perception. In: H. Feigl, H. Sellars and K. Lehrer (eds.), New Readings in Philosophical Analysis. Appleton-Century Crofts, pp. 148–177.

Monton, B. and Mohler, C. (2008) Constructive Empiricism. Stanford Encyclopedia of Philosophy (accessed on 26 June 2012)

Papineau, D. (2010) Realism, Ramsey sentences and the pessimistic meta-induction. Studies in History and Philosophy of Science, Part A 41:375-385.

Post, Heinz R. (1971) Correspondence, Invariance and Heuristics. Studies in History and Philosophy of Science 2:213-255.

Putnam, H. (1975) Mathematics, Matter and Method. Cambridge University Press.

Ross, D., Ladyman, J., and Kincaid, A. (2013) Scientific Metaphysics. Oxford University Press.

Saunders, S. (1993) To what physics corresponds. In: S. French and H. Kamminga (eds.), Correspondence, Invariance and Heuristics: Essays in Honour Of Heinz Post. Kluwer Academic Press.

Smolin, L. (2007) The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next. Mariner Books.

Stadler, F. (2012) The Vienna Circle: Moritz Schlick, Otto Neurath and Rudolf Carnap. In: J.R. Brown (ed.) Philosophy of Science: The Key Thinkers. Continuum, pp. 83-111.

Tegmark, M. (2014) Our Mathematical Universe: My Quest for the Ultimate Nature of Reality. Knopf.

van Fraassen, B.C. (1980) The Scientific Image. Oxford University Press.

van Fraassen, B.C. (1989) Laws and Symmetry. Clarendon.

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Woitt, P. (2006) Not Even Wrong: The Failure of String Theory and the Search for Unity in Physical Law for Unity in Physical Law. Basic Books.

Worrall, J. (1989) Structural realism: The best of both worlds? Dialectica, 43: 99–124.

36 thoughts on “Progress in Philosophy — III

  1. brodix

    “the deeper one digs the less one finds anything like physical objects at the bottom of it all.”

    One idea might be that we tend to focus on conclusions, rather than the processes creating them. A bit like walking up stairs, in that there are these series of events/objects/theories/models/etc, yet the process keeps moving on, even if it swirls around any particular form.
    Sort of like we define the energy of a wave in terms of its amplitude, but that is only attained when the energy has peaked. Similarly a theory is most clear when it is most defined, but then other factors and directions keep popping up.
    So when everything is “shut up and measure,” the process becomes secondary to the steps being taken.
    For instance, is an electron an entity, or is it a process? Would it exist, if all action were reduced to measurements?


  2. Robin Herbert

    ” the deeper one digs the less one finds anything like physical objects at the bottom of it all.”

    I guess you could put it another way and say that, more and more, we are finding that physical things are not as we expect them to be.

    But then again, our expectations of what ohysical objects should be ‘like’ are based on sensations we have of them. It is not surprising, then, that this sensation would turn out to be wrong.

    Liked by 1 person

  3. Coel

    I must confess to being pretty dubious about the distinctions being made in this piece.

    … “observable” means by way of normal human sensorial experience (as opposed to scientifically observable): …

    So if a stream of photons comes from a star, bounces around in our turbulent atmosphere, and then goes into our eye, then the star is “observable”; but if a fainter stream of photons comes from a star, bounces around in our turbulent atmosphere, then bounces off a couple of carefully placed mirrors, and then goes into our eye, then the star is “not observable”. I can’t see how that distinction has any philosophical relevance. Yes, observation always involves humans, but that’s a rather different point.

    More importantly,

    As van Fraassen (1980, 69) clearly explains: “the assertion of empirical adequacy is a great deal weaker than the assertion of truth …” …

    But what does “truth” mean here? It presumably means “correspondence” to reality, but the only handle we have on “reality” or “correspondence to reality” is empirical adequacy.

    Scientific ideas are expressed in human language (English letters or mathematical symbols or whatever), and unless one is going for the (utterly absurd) position that human language is built into the fabric of the universe, human-language ideas cannot be how reality ultimately is, so nothing we say can actually “be truth” in any sense stronger than being an entirely adequate model of the empirical world. Which then dissolves the distinction being made here.

    Science is a best-attempt at modelling the world that we observe around us, but human science is always fallible and always open to being improved upon, and can never be anything more than a best-attempt model.

    But, one then recovers realism to the extent that the idea of an external, physical world, of which we are part and which science models, is then the best and most parsimonious explanation for what we experience (being vastly more parsimonious than models which posit a whole meta-reality as well, such as BIV).

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  4. Martin Zach

    I think it would be worthwhile to point out that constructive empiricism remains agnostic not only about “unobservables” such as electrons but about cells as well – just to appreciate how bizarre van Fraassen’s position really is.

    “In the case of epistemic structural realism, the idea is that one is justified in being a realist about the relations between unobservables, while remaining agnostic as to their ontological status.”

    Are you certain that this is the correct way of putting it? I admit I am not familiar with the structural versions as much as I should be but as far as I know, the ESR doest not question the ontological status of the relata, though ESR denies we can know the nature of these relata – hence the distinction between structure and nature. Could you please elaborate on it in case I am mistaken? It would help me clarify things. Thanks!


  5. Coel

    Hi Massimo,

    I think you are worshiping that idea [Quine-style web], not just take it as a good metaphor.

    Guilty as charged! Indeed I do think that it is a lot more than a metaphor, one can go further and identify the “web of ideas” with the physical web of neural connections in our skulls (which is indeed a “web of ideas”).

    To find the roots of epistemology, we can go back into the distant past long before philosophy or science. Brains will have evolved to model the stream of data from the sensory organs and to use that data and model to make real-time decisions. Natural selection will then have selected for a correspondence between the neural-network world model and external reality (presuming that, on the whole, a better-corresponding model is more adaptive). The product of that is then the reasoning-machine that we use to do philosophy and science.

    Liked by 1 person

  6. brodix


    Yet the modeling process necessarily involves a “freeze-framing” of extremely dynamic processes. Consider how our eyes extract pictures from light that is traveling fast enough to cross the planet in the time our brain extracts enough information to create a clear image and cogitate over it a moment. Many activities usually require predictive and calculated responses which often bypass much of the cognitive model building.

    So when we are constructing these thought based models of reality, they do have a serious bias toward static forms, because that is how we process information.

    This relationship between process and conclusion instinctively runs through much of how we view reality. For instance, Dan and Socratic concluded the last thread with a debate over whether Hume was a skeptic, or a naturalist and Dan’s side of the argument was that he used skepticism as the process and naturalism was the conclusion. While Socratic saw the extent of the skepticism as evidence of his views and thus concluded he must be a skeptic.


  7. Imad Zaheer

    I always find it hard to really distinguish between the realist and anti-realist position and I think as I read more literature in POS, I find that it’s partly because positions like “realism” and “antirealism” are large families of positions rather than one or two.

    A good example of this is from Chalmer’s book (what’s this thing called science) where he talks about how at the most global level, we are anti-realist in that none of us believe that we explain the world independent of human language and perceptions. But this is a view that perhaps no one would disagree with and would be completely uninteresting to even mention.

    Instead, it’s more interesting to see where exactly more important distinctions can be made, how strongly we hold onto the existence of scientific universals and particulars.

    Along those lines, I see myself as perhaps somewhere in the middle, realists but modestly so in that I think the world exists largely independent of us and and we can say true things about it. There also are real universals and particulars, even though we discover them in a fallibist manner with not guarantee. However, I don’t think there is some grand truth or essence, I’d probably include the “structure” in structural realism in this as well (but having read nothing on structural realism, I’m largely speaking out of ignorance).

    I also don’t see the empirical adequacy as somehow different from being real or true in terms of how scientists use it. There is a fact of the matter of whether or not a theory is empirically adequate. Beyond that, I think constructive empiricism draws to sharp lines between observation and theory and that is perhaps where I would disagree with it most strongly.

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  8. Daniel Kaufman

    Massimo: For clarity’s sake, are you suggesting that a Scientific Realist must also be a Metaphysical Realist? It would seem to follow from this remark you make, early on:

    “Metaphysically, for a scientific realist the world exists independently of human minds, a stance which is of course open to the Kantian objection that we do not have access to the world-in-itself, only to decidedly not mind-independent experiences.”


  9. Daniel Kaufman

    Massimo wrote:

    The idea is that there are always, in principle, many different theories that are equally compatible with the data, or — equivalently — that the available data is not enough to determine the truth of a theory and the falsity of closely related theoretical variants. The problem with this objection is that it is actually difficult to find historical examples of rampant underdetermination, or of an underdetermination that was not soon resolved.


    It would seem to me that the much stronger Quinean argument against Scientific Realism, would come from his arguments for ontological relativity. There, remember, the arguments from the indeterminacy of translation lead Quine to conclude that:

    “What makes sense is to say not what the objects of a theory are, absolutely speaking, but how one theory of objects is interpretable or reinterpretable in another. ”

    (“Ontological Relativity,” The Journal of Philosophy, Vol. 65, No. 7 (Apr. 4, 1968), p. 201)


  10. Seth Leon

    As I have been reading along there has been something primary, nagging me about the peaks/topology metaphor for philosophical progress. This metaphor separates one peak from another each only connected by the valleys which correspond with long superseded ideas. Progress conceptualized this way then becomes identified to some degree with fragmentation and seems to fail to bring light on continuities between questions.

    I think I agree with Imad favoring Haack’s crossword puzzle foundherentism, and the classic pragmatist’s focus on continuity in general.

    On the realist/idealist divide I certainly think it is clear there is a world that exits out side of individual minds, or at a minimum we have to act with this type of belief system. I think science captures something of that ‘outside world’ in reliable patterns that our minds can perceive with their limited capacities assisted by language and the tools we have created. I don’t think this gives me any hope of gaining ontological truth about what really exists. Is there some big M mind that is universal as some thought (some ancient Greeks (logos), Peirce(agapism),the Dao, Nirvana, etc…), or some deterministic multi-world substance, or mathematical structures, etc…..I think I am a naturalist, but the I also think the idealist/realist distinction forces one to join sides of a false dichotomy.

    Liked by 5 people

  11. synred

    If mind is ‘brain-body dependent’ it’s not independent of the world, even if the world is pretty nearly independent of it.


  12. synred

    ‘Grass is Green’

    Scientific ‘knowledge’ is contingent on usually unstated axioms. We are more like mathematics than we’d like think, but allow observation and experiment into our ‘proofs’ under the assumption there’s something to observe and experiment on and that our minds our affected by said observations and experiments rather than creating them out of whole cloth.


  13. Seth Leon

    Yeah synred,

    I think any individual mind is ‘brain-body-environment’ dependent as it rolls with time, and environment includes the social/cultural. I think Dewey described mind this way as ‘transactional’. Outside of mine I have to assume their are other bodies, brains, and world environments in the past, to come in the future and beyond my reach at any moment.

    Liked by 1 person

  14. jbonnicerenoreg

    Great article, although it seems to me that some of the positions called realist would not be called realist in a naturalist sense but only in a Platonic or Kantian sense.
    Some of the criticisms seem to be based on not making the crucial distinction between observables and unobservables before physics.


  15. Robin Herbert

    Hi Coel,

    “Yes, observation always involves humans, but that’s a rather different point.”

    There appears to be some dispute on this matter. Everett’s original paper on the Many Worlds interpretation of QM is careful to stipulate the observers are mechanical devices. Sean Carroll says that an instrument panel or the molecules of air in a room might be observers. That seems to suggest he is saying that everything is an observer.


  16. Coel

    Just read it again, so a couple more comments:

    van Fraassen’s pragmatism even extends to the very idea of laws of nature . . . to which nonetheless the scientific realist seems wedded.

    These days, no-one would think of “laws of nature” as anything other than descriptions of nature (specifically, descriptions that can be stated in one sentence or one equation) would they?

    The fact that often enough theories in these other sciences don’t look particularly mathematical may be imputed to the relatively early stages of developments of those disciplines, but it may also represent a core limitation of a physics-centric way of looking at science as a whole.

    Mathematical descriptions only work in relatively simple situations, and many sciences deal with situations too complex for maths to be the right language.

    … perhaps the best current example of massive underdetermination of theory by the data is string/M-theory in fundamental physics … with its “landscape” of 10^500 (give or take) possible versions …

    I’m not sure this is a good example of underdetermination by data since, as you say, we don’t know whether it is correct at all, and further, if it were correct, then the data *would* tell us which of the 10^500 versions we were in. The problem about that is not that there is no *empirical* reason to pick out one from the 10^500, it’s that there is no *theoretical* reason to prefer that one from any of the others.

    A better example might be quantum mechanics, which, in contrast, is an accepted theory, and where the many different “interpretations” arise precisely because the data don’t tell us which to choose.

    The problem with this objection is that it is actually difficult to find historical examples of rampant underdetermination, …

    Probably because applying parsimony does the job of narrowing things down where data do not.

    Hi Robin,

    There appears to be some dispute on this matter.

    I’ll rephrase to “observations that humans can know about always involve humans somewhere”, since we’re discussing here epistemology and thus what humans can know.

    Sean Carroll says that an instrument panel or the molecules of air in a room might be observers.

    There he is not talking about epistemology, he is using “observer” in a technical sense of “thing that can cause a wavefunction collapse” or “… cause Many Worlds splitting” or whichever interpretation of QM you favour. There is no reason why this need involve humans (it does in Copenhagen, but that’s always been a pretty silly interpretation).

    Liked by 4 people

  17. synred

    Schrödinger invented his cat to show how silly Copenhagen interpretation was. Now many people (even physicist who should know better take it seriously). </;–)=


    >o< Meow! Meow! Meow! — Meow! Meow! Meow! — Meow! …
    \—–/ "I wish that damn'd atom would decay and shut-up that…"

    –the box would have to be sound proof too!

    Liked by 1 person

  18. Robin Herbert

    Hi synred,

    “Schrödinger invented his cat to show how silly Copenhagen interpretation was. Now many people (even physicist who should know better take it seriously). </;–)="

    Actually, his point was to ask if quantum physics in general could be considered a law of nature, or just a "calculus".

    Incidentally "silly" is a subjective judgement. Is there a QM interpretation that could not readonably strike someone as silly?

    I understand that Everettian QM is popular among school kids these days, partly because it implies that there is a Pokemon universe somewhere.


  19. Alan White

    Excellent review of the argumentative moves between realists and anti-realists.

    One thing that occurred to me while reading is the coincidence between the development of relativity and quantum theory in the early 20th century and the rise of philosophy of science. While science previous to the 20th century certainly evolved (whether assessed as progressing or not), it is interesting that the increased scrutiny provided by the philosophy of science has not contributed to toppling–or even beginning to undermine–these two difficult-to-reconcile theoretical traditions (as you point out about the lack of smooth explanation from the micro- to the macro-world). I wonder if that observation could be translated into a further point about progress in both science and philosophy. If quantum theory and relativity have been able to withstand the meta-criticism focused on them by philosophy of science, then perhaps this is a point against the meta-induction argument, thus bolstering both fields as progressive.


  20. synred

    I particularly dislike Many Worlds. There may be Pokémon (
    universes somewhere (Granddaughter Helen would be pleased) , and if I shoot myself in the head, in some ‘world’ the bullet will tunnel through my brain leaving my ‘free will’ intact.

    On the other hand in some world my finger just tunneled 1/2 an inch into the ‘t’ key on my laptop, I’m sitting writhing in agony and you’ll never got this silly post.

    The number of such worlds might be infinite or even unaccountable infinite. Occam could be spinning is grave in a bunch of ’em.

    Many QM interpretations seem ‘silly’ to me and a bunch more I don’t understand.

    For work-a-day computations Feynman’s path integral, ‘shut up and calculate’ approach seems least silly.

    I better stop. Every key I hit generates suffering me’s! ;_(


  21. Mark Szlazak

    Pessimistic induction! Really? That actually is not the case. Over the centuries, supernaturalism has been in retreat and probably has not been taken seriously in academia for a 100 years. Naturalism is what keeps on keeping on and expanding into frontiers like “consciousness” and the begin of the universe if it had a beginning. Anti-realism is just looking at the whole thing wrong. In fact, from a realist stance one would expect progress of theories by replacement with better ones within the naturalistic framework and that is exactly what has gone on.

    Liked by 4 people

  22. Robin Herbert

    I overheard my 13 year old son saying to his brother “Do you think there is a universe where they still take science seriously?” Potential for cynicism about science is significant.


  23. Robin Herbert

    Einstein’s take on realism:

    ““The physical world is real.” That is supposed to be the fundamental hypothesis. What does “hypothesis” mean here? For me, a hypothesis is a statement, whose truth must be assumed for the moment, but whose meaning must be raised above all ambiguity. The above statement appears to me, however, to be, in itself, meaningless, as if one said: “The physical world is cock-a-doodle-doo.” It appears to me that the “real” is an intrinsically empty, meaningless category (pigeon hole), whose monstrous importance lies only in the fact that I can do certain things in it and not certain others.

    Letter to Eduard Study, quoted in

    Liked by 1 person

  24. brodix

    Or as Sinatra put it, Dobedobedo.

    Doesn’t the distinction between doing and being come up as a rather fundamental factor to resolve?

    Being would seem to be the denominator; “Reality.”

    So what is this process occurring within this state of being? Atomic? Relativistic? Reciprocal? Reductionistic? Wholistic? Mechanical? Computational? Organic? Linear? Non-linear?


  25. Philosopher Eric

    We’ve now considered “truth,” “knowledge,” and “reality” here, though perhaps to mixed effect given the great divergence in educated views. But wouldn’t it be nice in these efforts to have an ultimate example of something which is “true/known/real”? Well it just so happens that a very prominent philosopher did once develop such an answer (though I am surprised by how little attention his solution receives). It can be stated as simply as this:

    I think…

    I don’t claim to “know” that a philosopher by the name René Descartes developed this amazing theory, or anything else beyond the fact that I personally do think. Furthermore it may be that others exist who are thus able to assert the same in reverse?

    For clarification, I define thought as “the processing element of the conscious mind” (and I’ll set aside the three associated forms of conscious input that I theorize, and one such output). I would hope for both the foundationalist and coherentist to begin with this premise — and then formally take what they think they know (evidence), and assess this against what they’re not so sure about (theory), as simple fallibllists.


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