I previously posted a draft version of a paper pointing out that “Relational Quantum Mechanics” (RQM), an interpretation proposed by C. Rovelli, is faced with serious, arguably fatal problems. That paper has gone through the review process for the journal Philosophy of Physics and is now provisionally accepted (pending minor revisions). Here is the final submitted version:
Forthcoming in Philosophy of Physics: “Relational Quantum Mechanics” is fatally flawed.
Published
Transactional Interpretation 
Very interesting and good article! I hope Rovelli will read it too! I can’t say that it is easy to understand for ordinary mortals; for example, I couldn’t fully understand all the arguments, but probably the fact that the RQM itself is a very vaguely sketched interpretation* plays a role in that.
But what I’d like to ask now is, have you read Jay Lawrence at al. article “Relative Facts of Relational Quantum Mechanics are Incompatible with Quantum Mechanics” (arxiv:2208.11793)? It doesn’t just reveal the logical/interpretation al difficulties, but specifically demonstrates that RQM predicts a different outcome than standard QM. Specifically, they also analyze Frauchiger and Renner’s (2018) Wigner’s Friend scenario; and derive mathematically that RQM is incompatible with QM.
Have you read this article? What do you think about it? Is their analysis correct? If so, I think it is worth a reference, as there are really many connections between this article and yours.
* I have read Rovelli’s book (Helgoland) – a very good book by the way – where he tries to put it in a clear way, but when he tries to explain Schödinger’s cat on the basis of RQM, it becomes incomprehensible there. I have run through this section four times, but neither I nor the people I have interviewed have been able to understand it. Where the fault lies: either I’m not clever enough, or Rovelli is not able to explain what he means well enough, or it’s just not logical… I don’t know.
(Note: Continuation after article arxiv:2208.11793: arxiv:2305.07343, arxiv:2310.18008v2, arxiv:2209.01237 and maybe others, but I lost the thread at this point…)
Thanks, I took a look at the paper and also at the reply of Drezet: https://arxiv.org/pdf/2209.01237. I think Drezet has a point that RQM evades the contradiction obtained by Lawrence based on an EPR state, since it’s obtained by violating RQM’s postulates in assuming that Bob’s ‘relative fact’ also applies to Alice. However, RQM does indeed get into trouble with the Wigner’s Friend-type experiments , as I show. And contrary to what Drezet says, RQM still founders on what counts as an “agent” when the authors (Adlam and Rovelli) resort to the mental gymmastics required by “agents” to try to hold on to a coherent RQM account. And it still helps itself to “outcomes” under undefined conditions (arguably undefinable conditions, given the conventional theory). Thanks again for your comment!
I am wondering whether the word ‘Transactional’ needs to be ‘transformed’ into the word ‘Transformational’… the word ‘Transaction’ seems to imply a certain symmetry in which nothing of real value has actually been exchanged. Which is why certain politicians and business people are labelled as ‘Transactional’ and do indeed function as machines exchanging meaningless streams of bits. But isn’t what is really happening in the ‘Transactional Interpretation’ a description of something, an ‘event’, that is, in reality, ‘Transformational’? Is it better to think of quantum physics as messaging the idea that ‘Relationality’ has the potential to be meaningfully ‘Transformational’?
No, I did not come up with this suggestion on my own! It was inspired to think about this through reading a very powerful book by David Jay called ‘Relationality. How Moving from Transactional to Transformational Relationships Can Reshape Our Lonely World’… http://relationalitybook.com/ David Jay is a physicist and author who is the grandson of physicist David Lazarus (1921-2011).
I’m aware that the word ‘transactional’ has acquired this infortunate connotation, but that’s fairly recent. Remember ‘transactional analysis,’ which is decidely not about an economic zero-sum situation but about people constructively engaging in a transformational process. There is also the Institute of Transactional Philosophy, https://transactionalism.org, which is dedicated to transformational, value-increasing processes. They use ‘interaction’ in the mechistic sense for which many now use ‘transaction.’
I don’t know the history, but perhaps somebody influential decided to use “transactional” as a pejorative for uncaring monetary mechanism, and that usage ‘grew legs’. Perhaps we need to take it back. I wouldn’t be able to use something like ‘transformational’ because that’s too general–it doesn’t describe what is going on physically, which is that there is an offer and a response/acceptance. The best term IMHO for this is ‘transaction’, but that does not mean that a transaction is not transformational. In fact, most real-world transactions are (e.g., an offer of friendship and an active acceptance).
Thank you very much… fair enough. What is interesting to me is that the whole idea behind ‘transactionalism’ in philosophy comes out of the school of pragmatism as developed by Dewey, I believe, that traces back to the ‘pragmaticism’ of Charles Sanders Peirce. And it is, as you say, about a constructive engagement in a process directed toward bilateral transformation, which also brings to mind David Bohm’s extensive discussion of the process of ‘Dialogue’ as a constructive process when it is engaged with a transformational intent. Thank you for the reference to the Institute of Transactional Philosophy. Yes, I totally agree that the key issue is what is the context in which the word ‘transaction’ is used. Transaction that is directed with an openness and perhaps even a hope of achieving a bilaterally beneficial transformation is very different from the current economic zero-sum intention in which, ultimately, the exchange is purely mechanical and without associated meaning. What seems important to me in the engagement in transaction as a form of bilateral, mediated communication is that there is an implied INTENT that is also directed toward bilateral positive ‘gain’. An atom that is ‘uncomfortable’ because of a heightened state of excitation takes advantage of transferring excess energy to another atom that is in a relatively under-excited state and is looking for more energy to bring it into a more satisfactory condition. Which relates to the idea that the Born Rule implies that ‘free will’ can be viewed as going ‘all the way down’–which you have written about, if I am not overstepping the boundaries of the interpretation. The transaction takes place and results in a mutual ‘benefit’ due to its transformational impact on both ‘sides’ of the transaction. In this context, I think the David Jay book is of particular relevance and interest! Because it places the emphasis on the relationality that makes all of this possible–which is a possibility that is ‘left out’ of a mechanistic physicalist formulation that classical physics engenders–machines passively ‘transact’ while organisms seek ‘transformation’.
I think that this idea that is implied of an ‘active agency’ involved in the process of transaction that connects to a move toward transformation has some fundamentally important implications. It is not something that just mechanically ‘happens’. There is something more involved.