Thoughts on “relational Quantum Mechanics”

Recently, the far-flung QBism discussion group nominally centered at UMass Boston has been conversing about Carlo Rovelli’s relational interpretation of quantum mechanics. Trying to think all this through halfway clearly, I wrote some notes. They don’t seem to be moving in the direction of a paper, and they’re too chatty for the arXiv even by my standards, so this seems the best place to host them.

Saturday Thought

One thing I just don’t get is people proclaiming “the End of Physics”. Like “the End of History”, it’s a very mockable phrase! Folks will be going, “Oh, our giant colliders haven’t found any surprises in years, and we never figured out an experiment to test string theory, so everyone’s drifting into quantum information and exotic condensed-matter physics, truly this is the sunset of an era.”

And I’m all, “So, instead of testing one effective field theory by putting matter into extreme conditions, you’re testing … multiple … effective field theories … by putting matter into extreme conditions.” I’m making my astonished face, can’t you tell?

Canonical Probabilities by Directly Quantizing Thermodynamics

I’ve had this derivation kicking around a while, and today seemed like as good a day as any to make a fuller write-up of it:

  • B. C. Stacey, “Canonical probabilities by directly quantizing thermodynamics” (PDF).

The idea is that Boltzmann’s rule $p(E_n) \propto e^{-E_n / k_B T}$ pops up really naturally when you ask for a rule that plays nicely with the composing-together of uncorrelated systems. This, in turn, gives a convenient expression to the idea that classical physics is what you get when you handle quantum systems sloppily.

More on Bohr

This post carries further on in the vein of my earlier writings on how the way most physicists talk about “the Copenhagen interpretation of quantum mechanics” is largely ahistorical.

It’s common to present “the Copenhagen interpretation” as a kind of dynamical collapse model, in which wavefunctions are ontic entities (like a sophomore’s picture of the electromagnetic field) that evolve according to the Schrödinger equation, except in moments of “measurement” that take place in unspecified conditions. This portrayal is typically intended to make “the Copenhagen interpretation” sound like a mutant form of Newtonian mechanics where $F = ma$ almost always, except at peculiar instants when $F$ suddenly becomes $ma/2$ and then switches back again. Of course, this is abhorrent and pathological.

When I was a child, my parents bought me a magnet from a museum gift shop. It had a long handle, likely made deliberately to resemble a magic wand, and as educational toys go, it served its function, since I went around poking all sorts of things to see if the magnet would grab them. I suspect this is a common enough type of learning experience. One discovers, for example, that it will pick up paperclips but not pennies. Having calibrated one’s understanding of the magnet, one can then use it as a tool — say, by telling which of two matchboxes is filled with paperclips, or that something is different about a wire coil connected to a battery versus one that is not.

What concerned Bohr himself was that this transition — between the calibration phase, when an object is under scrutiny, and its later use as a laboratory instrument — is conceptually nontrivial. First a lens is a strangely curved block of glass we must work to comprehend, and then it is a means to overthrow Aristotle. There are not two different dynamical laws, but two different languages.

Here’s how John Wheeler put it:

“Bohr stresses […] that the stick we hold can itself be an object of investigation, as when we run our fingers over its surface. The same stick, when grasped firmly and used to explore something else, becomes an extension of the observer or—when we depersonalize—a part of the measuring equipment. As we withdraw the stick from the one role, and recast it in the other role, we transpose the line of demarcation from one end of it to the other. The distinction between the probed and the probe, so evident at this scale of the everyday, is the without-which-nothing of every elementary phenomenon, of every closed quantum process.”

[From “Law Without Law”, in the Wheeler–Zurek collection, p. 206]

The commonalities and contrasts with QBism should be evident enough. Extension of the observer, yes; depersonalize to mere dead “equipment”, no, for it is the latter move that gets one into trouble with Wigner’s Friend. And, on a perhaps more practical level where the choice of research problems is concerned, Bohr takes the quantum formalism pretty much as given and leaves “the quantum principle” not explicitly defined.

It may also be illustrative to consider how Rovelli’s “Relational Quantum Mechanics” treats this point. I tentatively infer that Rovelli thinks giving a special role to an agent means imposing two different dynamical laws, one for systems of agent-type and another for all nonagent physical entities. Even if he doesn’t spell it out, that seems to be the mindset he operates with, and the background he relies upon. Of course, he balks at that dichotomy. I would, too!

What’s Wrong with this Sting Operation?

To the extent that academic peer review is good for anything, it is optimized to catch honest mistakes. It is weaker against deliberate fraud and stubborn denial. Science has a presumption of fair play, a sense that the natural world isn’t a cheater. If you want to explain how a “psychic” operates, you’re better off asking a magician than a physicist.

Nearly two decades ago now, there was a dust-up when a couple French TV personalities got a clutch of physics and mathematics papers published, and even received PhD’s, and their “work” turned out to be nonsense. (The Wikipedia article on l’affaire Bogdanov is currently not terrible, and it contains more pointers to details than almost anyone could honestly desire.) The news stories about the incident really played up the “even the physicists can’t tell if the papers are nonsense or not” angle. That rather oversells the case, though. I read the Bogdanovs’ “Topological field theory of the initial singularity of spacetime” when I was a first-year grad student, and I could see through it. If you know what a Lagrangian is, and the fog doesn’t intimidate you, then you can tell something is wrong. If you don’t know what a Lagrangian is, you’re probably not reading theoretical physics papers yet.

So, what went wrong?
Continue reading What’s Wrong with this Sting Operation?

Education, Inadvertent and otherwise

That feeling when it’s 3 in the morning and you’re watching an old PBS documentary aimed at grade-school kids and the mill workers are going on strike while Sumner declares that industries of the North are complicit in the slave economy of the South, and you’re like yes, exactly!

We’d all be so much better off, had the lessons of fourth grade only stuck.

(Also, the voice actor for the engineer/architect type character in a lot of those David Macaulay adaptations was Brian Blessed, which is pretty nice.)
Continue reading Education, Inadvertent and otherwise

In Which Pronouns Are Deliberate

I was thinking about how my re-implementation of a stochastic dynamical model actually predicted the stock-market instability that actually happened.

And about saying in January 2017, “I’m really not feeling that good about our ability to handle the next epidemic that comes our way.”

Now, turning out right when you’d much rather have been wrong is of course a complicated feeling. But I realized something. If you ever see a physicist getting out of his lane and opining about a subject that is not physics, you can direct him to me. I will then instruct him to bow before me, because I am his fucking god.

A Peculiar, Recurring Challenge

Not infrequently, crackpot physics papers attain a level of wrongness where trying to point to specific mistakes is useless, and a critique of the specifics collapses down to “just take a physics class” — true, but unhelpful to the curious bystander. The physicist, trying to say anything substantive, ends up picking out psychological “tells”, like the suspiciously convenient mention of too many famous big problems all in a row. There are no solid particulars of physics to discuss, so we end up talking psychology and sociology. I find the psychological questions that arise quite fascinating. Why, for example, is the population of pseudophysics perpetrators so heavily skewed to the male? But, in general, it is difficult to take physics and mathematics crankery and find interesting comments to say about it. All these years later, and the circle still refuses to square.

I’m reminded of self-proclaimed mega-genius Christopher Langan, whose “Cognitive Theoretic Model of the Universe” mixed incoherence, impenetrability and arrogance. As one of my fellow science bloggers put it back in the day:

I have no idea what he means by “replacing set-theoretic objects with syntactic operators” – but I do know that what he wrote makes no sense – it’s sort of like saying “I’m going to fix the sink in my bathroom by replacing the leaky washer with the color blue”, or “I’m going to fly to the moon by correctly spelling my left leg.”

My personal favorite might be the parenthetical clarification, “conspansion consists of two alternative phases accounting for the wave and particle properties of matter and affording a logical explanation for accelerating cosmic expansion”. Words words words words, words words!

A kind of “security by obscurity” sometimes operates in cases like these, where the total lack of solid material to criticize leads to indifference and silence from established scientists. This “why bother?” response then becomes fodder for the pseudophysicist to claim that the academy is too stuffy to understand his work, or even actively censoring it. The truth is less dramatic, though not without its own interest to old-fashioned students of human nature.


You may already have seen the news about publishers suing the Internet Archive.

As a scientist and teacher, I will not write or peer-review for any journal from these publishers, nor will I use their books in my classroom, because their emotionally immature stunt risks the collective memory of the Internet.

Whether or not the “National Emergency Library” is ultimately a reasonable idea, there are good ways and bad ways to approach the issue, and Hachette, HarperCollins, Wiley and Penguin Random House have chosen a bad one. For two decades, scholars have been asking, “What value do publishers actually add?” Answers vary, but a bitter “not bloody much” is prominent among them. Undermining our social and technical infrastructure in a time of global crisis only gives that view more weight.


Some time ago, I had one of those odd little thoughts that could be the spark of an essay. But in this particular case, the point I wanted to make felt like it could be made most clearly by demonstration, rather than explication. So, I wrote a concise report on “An Underappreciated Exchange in the Bohr–Einstein Debate.” Judging by the modest splash of positive e-mail that I received after posting it, I think I layered the whimsy and the serious point adequately well.


on the surface, it’s hip and winking nostalgia, but on the inside, it’s a sincere, desperately passionate, gut-level urge to affirm that our childhood had value

in the ache of this impossible, inescapable present

— where — in — the — world — is —

today, we are making gourmet

the only training I’ve had for this situation was writing a science fiction novel

The Adventure of the Scandalous Cauliflower

(very John Oliver voice) Good evening. Tonight’s top story: Web scraping. That’s when someone uses an automated tool to download, typically, large amounts of information from the Web and save it on their own computer for their own purposes. Now, there are situations where this is undoubtedly for the general good, like saving climate data so that it can’t be made to vanish with an act of government whimsy. But when personal information enters the picture, the ethical considerations can change, and there can be times when “it was available to the public!” becomes little more reassuring than, “Yes, I am following you while I happen to be carrying this camera, but you were walking outside, so you have to be OK with being seen, oh, and is this your regular bus stop?”.

Just a few days ago, the New York Times ran a provocative and alarming piece you have quite possibly already seen, titled “The Secretive Company That Might End Privacy as We Know It” — oh, you’ve read it? Thanks for telling us, but don’t worry, Mark Zuckerberg already knows. Basically, the M.O. of Clearview AI was to scrape pictures from, as the Times says, “Facebook, YouTube, Venmo and millions of other websites,” and then use the resulting massive database to fuel the wet dreams of petty aspiring autocrats everywhere.

Now, as with so many of the depressing and horrifying developments of modern life, there is a level on which this feels absolutely unsurprising. Just another way in which the utopian promise of the Internet [stock art of Tron appears over shoulder] was betrayed and perverted into something irredeemably toxic by some guy out to make a quick buck. Back in 1990, when (now Sir) Tim Berners-Lee created the first ever website at CERN, the physics laboratory that now hosts the Large Hadron Collider, surely this disaster was not what he had in mind. Even today, surely we can count on scientists to rise above the venal impulses of the money-grubbers, hold themselves to the highest ethical standards in the pursuit of truth, act with discretion to the communities that their research affects and I’m just fucking with you. Scientists are people. Sometimes greedy, often fallible. And the process of correcting an error, even one due to simple carelessness, can be remarkably painful for all concerned.

I have been involved in writing an open letter in response to what I myself like to call “The Adventure of the Scandalous Cauliflower.” That open letter is available here in PDF and basic HTML. I was not the first person to call attention to this matter, nor perhaps even the loudest, but I like formatting academic documents, so the organizing somewhat fell to me by default. As typically happens in cases where an open letter gets written, everyone involved has their own opinions that may stretch beyond its margins, and I’m sure that I have my own takes (or at least choices of emphasis) that would not be co-signed by all of the letter’s signatories. This blog post is, beyond providing a pointer to the open letter, my attempt to underline that my idiosyncrasies should not be attributed to anybody else unless they have expressly indicated that they share those particular takes of mine.

The very short version is that a group of researchers at the University of Milan hoovered up a large quantity of social-media data without informing any of the communities they were studying, violated the Terms of Service of a community in that set explicitly devoted to scholars and academics, and thanks to a truly impressive feat of analyzing without thinking, concluded that the topic of cauliflower is a serious transgression of their subjects’ social norms.

This is how the letter begins:

We are writing to raise grave concerns regarding the ethics and methodology of “Mastodon Content Warnings: Inappropriate Contents in a Microblogging Platform,” by Matteo Zignani et al. of the University of Milan. The issues with this paper are sufficiently severe that the paper’s dataset has been removed from Harvard’s Dataverse repository. This open letter will explain the background of this removal and urge further action on the part of the paper’s authors, the University of Milan, and the Association for the Advancement of Artificial Intelligence (AAAI), who have published the paper in their conference proceedings. As we detail below, the data analysed in this paper was not collected ethically, failing to take even simple steps to anonymize the data released with the paper, and fundamental errors of methodology make its results irrelevant.

Mastodon is a decentralized, community-operated microblogging platform created in early 2016 by Eugen Rochko and is based on open protocols that allow people to communicate across different servers. Anyone who wishes to create a Mastodon server, or instance, can do so by downloading and installing the Mastodon software. Users who register accounts at an instance can then share social-media posts with other users on that instance as well as with other instances. The interconnection of different servers is known as federation.

Other things that could have ended up in the letter if I had been left to my own devices and if it weren’t already going to be fairly long:

  • history of Mastodon’s “Content Warning” feature
  • variability in CW practices and discontent caused thereby
  • more details on the underlying ActivityPub protocol and its peculiarities
  • the ongoing development of fediverse software that isn’t Mastodon
  • the paper’s generally rushed, “we need a thing for this conference” feel
  • why it’s a good thing that professional codes of conduct can be a less blunt instrument than the law
  • the ambiguities fostered when the same software can be used as a means of publication and of social interaction

In short: Lots of indefinitely deep rabbit holes, and opportunities to say “a balance must be struck between the need for X and for Y” — though now that I’ve typed that phrase, I have to wonder how much that mode of rhetoric fuels compulsive centrism. Moreover, these are topics where it would be harder to pull together a core of agreement. I mean, would 45 other fediversians sign on to anything I wrote myself on my own about all that?

One way in which I am perhaps peculiar among the signatories is that, though I started this blog post talking about web scraping, in order to be topical and all, that’s not really the background from which I approached the topic. Indeed, this incident seems significantly dis-analogous to many if not most of the times I can recall that web scraping has become a hot-button issue for one reason or another. We’re in the realm of (potential) research misconduct, of science being done badly, and how lapses in ethics cannot always be pried apart from flaws of methodology. I think that the oversimplified “responsible conduct in science” lessons that we get spoon-fed in school tend to create the impression that ethical issues are when the results of a study are reliable, but the study was conducted in an objectionable way. However, that separation is too clean. Why should a study conducted with a lack of care be taken as reliable?

So, I could instead have started this blog post by invoking my very John Oliver voice and intoning, “Our top story tonight: Ethics. Otherwise known as the reason why just because you could, that doesn’t mean you should.”

But even that doesn’t quite get at the core of the matter.

If, for example, you are doing a study of 363 different online communities, each running its own server, and you don’t have the resources to examine the Terms of Service for each of those 363 installations and see if what you’re doing is in accord with all of them, then how can you say that you have the resources to evaluate the data you gathered on them?

As strange as this may sound, I don’t actually like it when I come across as mean. Every day, I wish I could use the Internet as a device for being kind to people I’ve never met.

But if science is to be a thing we value, we must hold it to account. That can mean booting scientists from the National Academy for sexual harassment, or taking an uncomfortably hard look at what telescopes we think we “need” to build, or even a critical analysis of a scandalous cauliflower.

On the Writing Process

The problem I typically have when writing about technical topics is trying to include everything and to answer objections that seem vitally important to me but which don’t make much sense unless you’ve heard the debates inside my head. Removing that stuff has by now become a standard part of my revision process. My colleagues point it out, I feel a little hurt, then I grudgingly agree, and in a week or so I re-read my work and I don’t get why I thought that extra stuff was so important in the first place.

I’ve also noticed that the parts of an argument that people object to are often the bits that I thought were almost incidental, or that exist mostly in their head — they want to keep having the argument they’ve been having before. Trying to foresee how this will play out is hard, and it always helps to have input on that.

I count myself lucky to work with people who care about this kind of thing. I wish I’d had more training in my early years of physicist school — some harried lab reports and a single term paper don’t add up to much, honestly, given how much of our professional output is the written word.

My 2019 in Science

First, of course, there was the doubt and the pain.

But we’ve already covered that.

Let’s talk about the papers I managed to get out the door and into public view. In retrospect, the list is pleasingly not insubstantial:

There was also From Gender to Gleason, my review of Adam Becker’s book What is Real? (2018). By the time I was done, it was as lengthy as a paper, but the arXiv isn’t really a host for book reviews, so I just posted it here at Sunclipse and moved on.

Predator/prey or Perish

Looking at academic publishing from the perspective of Fully Automated Luxury Gay Space Communism is an interesting experience.

Consider, for example, the term predatory publisher for shady outfits that will accept anything for the right fee and put it on a website that calls itself a “journal”. Scummy behavior, right? But is it really “predatory”? What fraction, exactly, of their customers are being conned, and how many are walking into the deal with their eyes wide open? A used-car salesman might be a sleaze, but if you’re going to his dealership to pay cash for a getaway car, the relationship is more of a symbiosis.

I’m sure it’s convenient for the legacy institutions to present the situation as saintly scholars being exploited by deceptive newcomers. [cough]

Suppose the Web came to be, but there never were any respectable Open Access journals. No “Open Letter to Scientific Publishers” in 2001, so no Public Library of Science; no Budapest Initiative in 2002 or Berlin Declaration in 2003. Would the morass of “predatory” OA really look all that different? Perhaps not. Websites are cheap, calling yourself a journal is easy, and as we just noted, there’s a ready market.

But without the cover of PLOS and the like, would “predatory” OA have a veneer of respectability to offer its customers? Well, consider that paying to attend conferences is a thing that academia finds universally respectable. So, a “predator” could do what outfits like WASET do now: offer “conferences” with no standards, no dedicated space, perhaps not even a physical event. And if you’ve got a paper, great! For only a modest additional fee, it can go in the conference proceedings, which will conveniently be available online.

Quality is always the hard course of action. Legitimate OA journals were optional; only the pay-to-play racket was inevitable.

"no matter how gifted, you alone cannot change the world"