“Scientists need philosophers of science like birds need ornithologists,” so said Richard Feynman yet Carlo Rovelli, one of the era’s more deeper thinkers boldly branching out beyond the sterile disciplinary boundaries, has written a most thought provoking paper on the relationship between philosophy and physics. The focus of the paper seeks to account for the underlying source of the malaise affecting theoretical physics finding it in the adoption of an unwitting philosophical attitude that inhibits progress. We have a curious mixture of an antiphilosophy philosophy that celebrates the progress of science and lampoons the stasis of philosophy, which is alive in the same sense as Lenin, but which itself rather ironically prevents scientific progress.
That is a right royal mess, and to get out of it physics needs philosophy and philosophy can better be of service to physics if it is more mindful of science. That is, briefly, the gist of the Rovelli paper.
How could we have gotten ourselves into such a pickle?
Rovelli makes an important point about the nature of science itself and ideas that scientists, and others, have had about its nature
Here are some sliding definitions for what scientists have thought science to be: deduction of general laws from observed phenomena, finding out the ultimate constituents of Nature, accounting for regularities in empirical observations, finding provisional conceptual schemes for making sense of the world. (The last one is the one I like.) Science is not a project with a methodology written in stone, or a fixed conceptual structure. It is our ever-evolving endeavor to better understand the world
The last one is the one I like as well. Science provides us with theories of the world that make the world intelligible to us. That’s not the same as saying that science provides us a clear and unmediated view of nature as nature fundamentally is, for that always was and always will be a mystery for us.
Notice that there’s a lesson here for philosophers, especially epistemologists. That means the problem of scepticism becomes a type of dumb question for where there is mystery there is always room for scepticism. Epistemology is one branch of philosophy stuck in as much, if not more, of a malaise than theoretical physics and an obsession with scepticism, an issue unresolvable, lies at the root of this malaise one might say. Here it is physics that can be of much assistance to philosophy, so long we take knowledge not to be a species of justified true belief but rather a natural feature of the physical world. Knowledge is of the physical just as mass, energy, heat and so on are. Knowledge should be an integral part our conceptual scheme for making sense of the physical world. Epistemology is really ontology. Rovelli does, very briefly, make the point that philosophy could do with a good dose of science pointing to an antiscientific attitude in what he refers to as “post Heideggerian philosophy.”
Just as the best science listens keenly to philosophy, so the best philosophy listen keenly to science. This has certainly been so in the past: from Aristotle and Plato to Descartes, Hume, Kant, Husserl and Lewis, the best philosophy has always been closely tuned in to science. No great philosopher of the past would ever have thought for a moment of not taking seriously the knowledge of the world offered by the science of their times
The opprobrium is thereby directed toward continental philosophy but so doing isn’t terribly interesting. Of much more interest are those areas of philosophy that claim to be coterminous with the sciences namely analytical philosophy and naturalistic philosophy but really aren’t.
Rovelli’s concern, naturally, is with how philosophy might be of service to physics rather than physics to philosophy so that is also our concern.
The malaise to which we refer, of course, refers to the lack of further progress in our understanding of the physical world beyond the standard models of both particle physics and gravitation. This stands in contrast to the flowering of theoretical endeavour in both domains through much of the 20th century, especially after the renaissance of gravitation, cosmology and astrophysics following World War Two. The progress in theoretical physics was not just limited to elementary particle physics.
Rovelli argues that philosophy can play a role in advancing our understanding of nature, as it always has, and fault today can be found in an underlying philosophical attitude in physics encouraging what Helge Kragh has called “higher superstition.” By higher superstition is meant radical physical theories not well grounded in or by experiment.
Rovelli establishes the first point by pointing to historical examples where philosophy played a role in theoretical advance, for instance with logical positivism and both quantum mechanics and relativity. Here Rovelli puts great store on the verification principle, and so here one must be careful. Within philosophy there exists the view that the verification principle was not as key to logical positivism as often claimed, certainly of the logical positivism developed in Europe before the war, and that the main concern of logical positivists was the relative a priori and that concern, in turn, arose because advances in mathematics and physics struck up against Kant’s conceptual schemata so the relationship between philosophy and physics would not be as linear as Rovelli seems to suggest.
Further examination of this would make for an important and interesting historical study.
Rovelli argues that the antiphilosophical attitude displayed in statements from Steven Weinberg, Stephen Hawking and Neil de Grasse Tyson, among others, can also be attributed to the dominance of logical positivism in post war intellectual life especially its aversion to metaphysics. Yet that means, unwittingly, Weinberg et al are themselves betraying a philosophical stance. That is surely true. There is more that could be said here, especially regarding naturalism in philosophy but the focus here must remain on science if only because I promised so.
This line of attack draws us to Rovelli’s main point and that is that many physicists display such an unwitting commitment to an underlying philosophy which is inhibiting theoretical progress, that being Popper and Kuhn’s extensions to logical positivism. Again, it should be stressed that viewing both as extensions of logical positivism is historically contentious but let us proceed nonetheless
Kuhn’s emphasis on discontinuity and incommensurability has misled many theoretical and experimental physicists into disvaluing the formidable cumulative aspects of scientific knowledge. Popper’s emphasis on falsifiability, originally a demarcation criterion, has been flatly misinterpreted as an evaluation criterion. The combination of the two has given rise to disastrous methodological confusion: the idea that past knowledge is irrelevant when searching for new theories, that all unproven ideas are equally interesting and all unmeasured effects are equally likely to occur, and that the work of a theoretician consists in pulling arbitrary possibilities out of the blue and developing them, since anything that has not yet been falsified might in fact be right
That is why, in part, we have “higher superstition” not supported by empirical evidence, perhaps not supportable in principle, and the lack of concern with this state of affairs in much of the physics community prevents theoretical progress. Rovelli argues, contra what he takes to be Kuhn’s message or what scientists have taken to be Kuhn’s message, that science is cumulative and that scientific revolutions are not fruits of the proverbial bolt from the blue, epistemic breaks as it were, but rather are forced upon us by the empirical data or careful analysis of conceptual contradictions or paradoxes within a prevailing body of theory
The radical conceptual shifts and the most unconventional ideas that have actually worked have indeed been always historically motivated, almost forced, either by the overwhelming weight of new data, or by a well-informed analysis of the internal contradictions within existing, successful theories. Science works through continuity, not discontinuity
I agree with Rovelli here. This has been a theme of some of my previous posts of a philosophical nature, especially those that make the argument that scientific revolutions have the tendency to resolve incommensurability rather than reflect or lead to incommensurability. However, I am not so sure that the higher superstition to which Rovelli refers is much influenced by Popper and Kuhn. Indeed, those who argue against the cosmic landscape have been dismissed as “Popperazzi” given their supposed commitment to naïve falsificationism. I suspect also that most physicists have not paid Kuhn anywhere near the same attention paid to him in the social sciences, which is probably why their Kuhn is much like the Kuhn of the social scientists.
That said, you don’t have to accept the Popper and Kuhn lurking beneath argument to see that Rovelli has a powerful point.
Firstly, regarding the matter of conceptual paradoxes holding out the promise of advancing theories of the physical surely the increasing attention paid to the foundations of quantum mechanics, by both philosophers and physicists, is a good example of this at work. The link between philosophy of mind and cognitive science is another example of the two domains productively working in tandem. I have kind of long had the view that study on the foundations of quantum mechanics is where there has been, and continues to be, fascinating inquiry within both philosophy and physics that challenges our conceptions of the physical. Such work goes far beyond narrow technical considerations that do not subject our ideas about the physical to critical scrutiny. Nothing said here contradicts Rovelli no matter what you think of his rendering of Popper and Kuhn.
Secondly, one might argue that the empirical data is screaming at us and that it is forcing us to reconsider our theories of the physical. It is possible to argue that the cosmological constant problem, anomalies of the hot big bang model, among others demonstrate to us the weakness of both quantum theory and relativity. Our prevailing theories of the physical world do not match experiment. Notice that this is contrary to the argument that sees the current malaise in the lack of empirical data beyond the standard models of particle physics and cosmology. This has things in reverse. Such empirical data exists, only it refuses to bend to theory. Both quantum theory and general relativity do not predict a small positive value for the cosmological constant which we observe. Perhaps we need to reconsider some of our fundamental physical categories to achieve a better match between theory and experiment. Kuhn might not have disagreed, after all experimental anomaly for him was the lifeblood of scientific revolution.
For Rovelli physics is dominated by empirically ungrounded speculation because it is dominated by string theory and the cosmic landscape, and such speculation has the imprimatur of Popperian and Kuhnian philosophy. I can’t help but think that this draws too long a bow. What is needed for progress is a more down to universe conservativism grounded firmly in what we already know, something like loop quantum gravity Rovelli concludes.
It is possible to go the other way. It is possible to argue that the malaise in theoretical physics, partly, is due to a search for something that cannot be found namely a quantum theory of gravity. That the search for this, something uniting both loop quantum gravity and string theory, is reflective of a deep conservativism so conservative in fact that testable predictions are hard to find. For all the universes, branes, and spinors of both theories it is not possible to find a testable prediction amenable to experiment that challenges quantum mechanics or general relativity or both.
After 70 years of mental labour by some of our more powerful minds quantum gravity remains a mirage. It took us less than 70 years to see that logical positivism was a mirage and that was in philosophy not physics. Consider an article published today in Scientific American on quantum gravity. In particular consider the opening, foundational, sentence
All the fundamental forces of the universe are known to follow the laws of quantum mechanics, save one: gravity
Yet gravitation is not a force, rather it is a result of spacetime curvature. Quantum gravity is definitely based on a philosophical, if you will, view regarding the physical namely that quantum mechanics is a complete picture of physical reality in ways general relativity is not. Never mind that gravity does not fit into the quantum mechanical view of nature. Because quantum mechanics is complete gravitation must be made to fit through some theory of quantum gravity, seems to be the dominant reasoning at play. Never mind also that philosophical conundrums regarding the physical opened by the singularity theorems also are applicable to quantum mechanics, which is hardly conundrum free at the conceptual level.
Both quantum mechanics and general relativity are incomplete. History suggests so. Philosophical conundrums that go to the heart of our understanding of reality suggest so. But most importantly experiment suggests so, and that not by the experiments of tomorrow but the experiments of today. Until either or both theories give us a value of the cosmological constant that matches observation they are incomplete. Quite why two theories can be made to match observation when put together when both separately do not do so is not so clear. If there is shoddy philosophy that underpins all this then that is bad, and Rovelli is right but kind of unwittingly so.
Should it be the case that there is no road to quantum gravity theoretical physics will again make headway when it gets off that road to nowhere. I’m not certain as to how much of a service philosophy can be. Philosophers have shown themselves to be very good at driving down roads to nowhere.
Besides there are other factors at play beyond philosophy and science that inhibit progress, for example the nature of intellectual life in increasingly commercialised and market driven universities. As Daniel Dennett has pointed out the go in philosophy now is publishing pointless papers that make some rather trivial points on some minor matter of analysis compelled by some anti-intellectual productivity metric. Under such circumstances philosophy is not of much interest to anyone let alone physicists.
An empirical demonstration of this point can be found at the arXiv, where Rovelli’s paper was first published. It has a grand total of one citations. The way the neoliberal university measures these things, that’s low impact.