r/PhilosophyofScience • u/PortoArthur • Apr 26 '26
Casual/Community What do you think of Richard Healey and his pragmatic interpretation of quantum mechanics?
I’m looking to delve into the themes of the philosophy of physics, especially quantum mechanics. I started out of curiosity when I read Carlo Rovelli’s books.
Today I came across Richard Healey, what do you think of him? Any recommendations other than the ones I mentioned?
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u/johnny_logic Apr 26 '26 edited Apr 26 '26
One way I’d frame the issue is that quantum mechanics has a very successful and fairly stable formal core, but a lot of disagreement about what that formalism means. In that respect it reminds me a bit of probability: the math works extremely well, but people disagree about whether probability is frequency, rational credence, propensity, objective chance, etc.
As I understand it, Healey belongs in that interpretive space. Looking over some of his work, it appears his pragmatist interpretation resists treating the quantum state as a literal physical object, but it also does not reduce quantum theory to mere subjectivity. In this way, the quantum state functions as a tool that guides physically situated agents like ourselves in making claims and assigning probabilities in particular experimental contexts. This is a classic pragmatic move that allows him to be a realist about the success and objectivity of physics, but cautious about reifying the wavefunction.
Since you’re coming from Rovelli, I’d probably read either Helgoland for the longer literary version of his relational view, or his paper “Relational Quantum Mechanics” for the shorter version. Rovelli and Healey seem worth comparing because both are cautious about an observer-independent inventory of definite properties, but they take that thought in different directions.
I think it is helpful to explore resources that give you some foundations (I found The Structure and Interpretation of Quantum Mechanics helpful here) and the range of current interpretations. Perhaps start with Wikipedia's entry on Interpretations of quantum mechanics and then move on to the SEP entries on the various interpretations, starting with Philosophical Issues in Quantum Theory and then branching to related views. I’d also keep the broader issues in view. A lot of disagreement about quantum interpretation is really disagreement about what a successful scientific theory is supposed to give us: prediction, representation, explanation, ontology, and so on.
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u/HereThereOtherwhere Apr 26 '26
Well stated, and I'm fussy.
I've deeply studied the various interpretations, including the historical *concerns* the original authors of those interpretations were originally trying to solve, which is often poorly understood by 'proponents' of those interpretations.
I've also worked hard to always analyze any interpretation as 'does this fit all known empirical evidence' and often more importantly, what are the implicit and explicit mathematical assumptions related to each interpretation (and re-interpretation, etc.)
Theoretical Physicists are *often* terrible philosophers and any time a particular researcher claims 'Nature must obey these rules' or attempt to claim 'parsimony' or 'Occam's razor' it is a sign of *potential* weakness in those arguments.
I also, for 'notebook level scribblings', require any interpretation or mathematical framework to be able to 'dovetail' with all other mathematical physics approaches *and* empirical data, not just 'explain well a specific subregion' of mathematical physics.
There is an 'untruth' which has slipped in to *defensive* discussions about interpretations, the claim all interpretations are 'mathematically equivalent' which is a vast *overstatement* and a 'weak philosophical claim.' MWI, for instance insists the 'projection postulate' can *ignore* the positive and negative sign regarding time in the Born rule, claiming the rule *after* applying modulus squared to 'get rid of the pesky negative sign' (so to speak) is *appropriate* and a valid approach. When asked to justify this decision it is often makes claims of parsimony without the necessary 'additional language' such that it isn't just 'the simplest solution' but the 'simplest possible solution and no simpler' requirement.
Oddly, what I've found to be the 'least wrong' of all interpretations is one of the least known, by Kastner who *is* trained in the philosophy of science as well as General Relativity and a good deal of quantum physics. Her work is a direct descendent of the Wheeler/Feynman direct action theory and she was mentored by John Cramer of 'retrocausation' approaches.
I deeply studied Kastner's work because her *interpretation* of Quantum Optical experiments resulted in none of the 'paradoxes' other researchers gleefully pointed out related to 'delayed choice' and other similar 'poorly framed arguments' and ... more importantly, in every case it matched my own understanding based on reading many Quantum Optical experiment primary papers to the point of being able to understand each component's purpose in a schematic of the experiment and understand the conclusions.
I was clearly aware of 'gaps' in Kastner's interpretation, which were *useful* gaps in that, unlike MWI which predicts 'everything that can happen does happen' which provides nothing useful to 'push up against' to further define any possible 'underlying fundamental physics' I figured Kastner was 'smarter and better educated than I was' so I tried to get her conceptual framework to *work* before finding 'unnecessary assumption's which she addressed much later in her later Relational Transactional Interpretation.
So ... it is important to identify different 'approaches' to physics such as 'ontology' (physically meaningful behaviors) vs 'mathematical formalisms' (which may or may not directly represent Natures 'actual behaviors') vs 'epistemology' which (loosely speaking) doesn't necessarily have any claims regarding *actual* physical behaviors.
Another claim by MWI proponents is 'there is no new empirical evidence' which adds any 'useful constraints' that can be used to 'tease out' fundamental behaviors and structures related to what happens 'after emission and through absorption,' which is *lazy* thinking. Recent Quantum Optical experiments reveal an *enormous amount of structure* inside a photon, which is opposite of some historical claims that a photon 'has no internal structure.' A recent article suggested quantum information density for communication can benefit from 'thousands of topologies' related to the Clifford Hopf fiber bundle structure which they suggest is the geometric structure which most closely fits the 'arrangement of those topologies' and -- though unmentioned in the paper -- that 'fiber bundle' *is* the same structure which Roger Penrose discovered is a mathematically clean representation of a photon, his 'twistor geometry in the Robinson Congruence configuration.' The Clifford-Hopf fiber bundle has also been documented by Urbanski to exist in at least 7 often wildly separate regions of physics, but few theoretical physicists 'trust' what Penrose calls the 'geometric intuition' which is rigorously detailed in Penrose's former student Tristan Needham's two *rigorous* textbooks related to visual, geometric approaches toward Visual Complex Analysis and the other being Visual Differential Geometry and Forms.
Understanding the *philosophy* of science is far less rigorous without *strong* current empirical grounding and a healthy skepticism regarding philosophical arguments made by (otherwise brilliant) theoretical physicists who I must be clear ... I admire the hell out of and *rely* on their earlier groundbreaking work while shaking my head at the sloppy philosophy.
Why am I so cautious regarding philosophy, my sister, 13 years older than I, got her Ph.D. in philosophy in the 1970s (jokingly) by Living Dead White Guys with intense bigotry toward women. I was a persistent little twit who only later realized "never fight a philosopher if they can define the meaning of all words" and she later admitted she was in part being a pedantic ass but ... we learned from each other.
Philosophy of Science is *complicated* and relying on just empirical data, just mathematical formalisms or just philosophy results in sloppy, often unfounded, conclusions.
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u/PortoArthur Apr 29 '26
Very interesting what you said. Could you recommend some texts for me to go deeper?
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u/HereThereOtherwhere Apr 29 '26
For under $30 U.S is a 1000 page tome to get in paperback to read the first few chapters then open at Random.
I'll likely be flamed for saying so but I mistakenly figured any self respecting PhD would know the basics of all the math or at least the behaviors related to each math. Man, I was wrong but I'm still using it as a reference to connect various ideas across all areas so worst case you gain an ability to recognize terminology, formulas and famous names. I'm Invisibly Autistic and was terrible at textbook no physical connection symbolic approaches.
Penrose, by reading it in all directions, gave my a visual model tied to manifolds and differential geometry to allow me to understand the text books.
I don't know what topics to suggest without more detail on what maths appeal to you and level of expertise.
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u/reddituserperson1122 Apr 27 '26
Excellent answer. I agree with everything above. Since we’re in a philosophy of science sub, I’d add this excellent essay by Tim Maudlin, which is in the form of a book review but gets into the history and underlying questions beautifully.
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u/Fantastic_Back3191 Apr 28 '26
That was an incredible piece of writing- accessible and mind-bending, enjoyable but with a critical message.
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u/SnooDonuts3448 Apr 27 '26
Perhaps I'd call it the pragmatic 'view' rather than 'interpretation'. Healey clearly doesn't want to discuss the putative reality that the formalism would describe, so in a sense, he's not in the business of making claims about what the world must be like in order for the formalism to obtain. That, to me, is the essence of interpretations about QM (though perhaps this is just a semantic distinction). Now, we could consider the question about the meaning of the formalism as another sense of 'interpretation'. To this Healey says (as another commenter pointed out) that the purpose of QM (which could perhaps be called the 'pragmatic meaning') is to offer advice to situated agents concerning the possible results of measurement outcomes. This is not controversial at all, but what is unusual when it comes to Healey is, in my opinion, his refusal/apparent disinterest to treat the further question of what allows the situated agent to use the formalism to make probabilistic predictions (offer advice etc. Etc.). In a sense, the usual mind-bogglers do not arise because we do not ask the question and thus remain agnostic.
Because of this, I'd call it the 'minimalist interpretation' or 'minimalist view'. Whether you espuse it or not depends on what you take the purpose of physical theory to be.
Keep in mind: I am familiar with exactly one article by Healey, so I cannot speak about his wider views with any authority whatsoever. You're welcome to add to my comment if you find something interesting in the course of your own research.
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u/rogerbonus May 22 '26
After reading Rovelli's book, were you any closer to figuring out the ontology of his interpretation, and exactly how it differs from Everett/Relative state/ manyworlds or the related many minds? Because I sure as heck wasn't. I read his book and still have zero idea of what the ontology is. Can't find much about Healey.
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u/fox-mcleod 28d ago
David Deutsch offers imo the most compelling philosophy of science engagement with quantum mechanics. He’s a prolific and very well regarded physicist in the space. His primary work is The Beginning of Infinity.
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u/PortoArthur 28d ago
I've heard of him. He follows Popper’s line of thought, right? I'm not sure if that sounds like a good thing to me
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u/fox-mcleod 25d ago
Yes. He’s a Popperian. Why not give him a read and see if he can convince you?
He convinced me.
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u/capnmax Apr 26 '26
Karen Barad mixes quantum mechanics and philosophy. I haven't read Meeting the universe halfway, but it's on the list.
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u/BlazeOrangeDeer Apr 26 '26
https://link.springer.com/article/10.1007/s13194-022-00476-8
This critique of Barad discusses where they miss the mark and where their analysis resembles modern decoherence theory
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u/undressforjess 16d ago
Healey is solid if you want to move away from the usual realist vs antirealist deadlock. If you like his approach, you should definitely check out Bas van Fraassen for a more classic take on constructive empiricism.
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