Sunday I breezed through Seven Brief Lessons On Physics (2014), by Carlo Rovelli. It’s a quick read of only 96 pages that still manages to touch on some of the key aspects of physics.
His much longer book, Reality Is Not What It Seems: The Journey to Quantum Gravity (2014), covers the same territory in greater detail (and greater length: 288 pages). After I finished what amounted to an appetizer, I tucked into the main course. I’m about 30% through it and am enjoying it quite a bit more than I have his work so far.
Both books, but especially the longer one, explore the theory of Loop Quantum Gravity (LQG), of which Rovelli is a co-founder.
Note that the publication dates listed are the Italian publication dates. The English publications were 2105 for Seven Brief Lessons On Physics and 2016 for Reality Is Not What It Seems.
I’ll also mention that much of the text in the brief one appears in the longer one. If one plans to read the long one, it’s possible to skip the short one, but it does make a nice appetizer.
I read his book The Order of Time (2017) and struggled somewhat with it on both style and argument. I’m not taken by his theory that time is emergent. In my view that’s cart before the horse. [See Time and Two Doors for details.]
My previous post was about a book by Paul Halpern, and there I mentioned how much I enjoyed his clean efficient writing style compared to the ornate style of other authors I’ve waded through. (What’s embarrassing is recognizing my own tendency to be baroque. Might be why I’m sensitive to it.)
To my eye, Rovelli is one of those baroque authors. I struggled with that, along with what I saw as a tendency to hand-wave, all though The Order of Time.
Seven Brief Lessons On Physics also felt ornate to me as well as overly casual in the brevity of some topics. (Not inaccurate, but far from the approximation I would have chosen.)
A lot of people really like Seven Brief Lessons On Physics — it gets a lot of what I’m sure are well-deserved rave reviews — but the best I can give it an Eh! rating. (Granted, I’m not at all the audience for the book.)
I know very little about LQG and don’t have an opinion there, but I believe time to be fundamental whereas Rovelli believes it’s emergent. I also am not sympathetic to views that place relations as a primary unit of reality. I think that’s another cart-horse confusion.
The post on his book about time explores why I think time can’t be emergent, I won’t get into it here. My problem with relationship-based views is that, by definition, a relationship is between two things. Without the things, there is no relationship.
I should mention that my rejecting a view doesn’t necessarily mean eliminating it from any consideration. It means putting it on the bottom of my stack of likely answers. It means I’d have to be satisfied it wasn’t any of those answers first. (Hard, repeatable, experimental evidence is always persuasive.)
Our understanding of reality is contingent on new knowledge. Nearly every physics book written touches on how our view of reality has evolved.
Speaking of which, Rovelli goes into that in detail in Reality Is Not What It Seems. He goes back to the earliest Greek thinkers in exploring how scientific thinking itself came to be.
I did find that kind of interesting (although I’m not much of a history buff, especially ancient history).
Somehow, at least so far, his writing seems cleaner and more engaging to me. I frequently became absorbed in Halpern’s narrative — that didn’t happen in the first two Rovelli books I read, but it’s happening here in the third.
It may be that his telling a history story doesn’t give me a case of the Yeah, Buts, whereas some of his physical speculations and stories do.
One thing I credit Rovelli on is being clear on what we know (very little, really), what we think we know (a fair bit), and what he’s speculating on. More importantly to me, there is no sense of evangelism.
Since I’m only a third through, and we’re still on history, I won’t go into it too much. (Unless I run into something especially striking, I don’t plan to review it once I finish.)
Here are some of the bits I noted so far (mostly from the brief book)…
¶ One of Rovelli’s key arguments about time not being fundamental involves Special Relativity: “the theory that elucidates how time does not pass identically for everyone.” (Something that’s even more true under General Relativity.)
As stated, it’s false. Time does indeed pass exactly the same for everyone. However observers in one frame may see time in another frame passing differently (but the people in that frame don’t). That’s why it’s call Relativity.
My view is that the rock-solid consistent ticking of proper time, if anything, is an indication of time’s fundamental nature. The clock for every particle in the universe ticks the same for that particle.
So when Rovelli asserts that (and he does often), it grates. What he means is there’s no universal clock — a Newtonian idea. Which is true.
¶ One bit that appears in both books crystallized something for me: “But general relativity is a compact gem: conceived by a single mind, that of Albert Einstein, it’s a simple and coherent vision of gravity, space, and time. Quantum mechanics, or “quantum theory,” on the other hand, […] more than a century after its birth it remains shrouded in mystery and incomprehensibility.”
Elsewhere he explicitly mentions what’s implied here, that quantum mechanics is the work of many minds and something of a patchwork in embodying electromagnetism, the weak force, and the strong force.
What crystallized was why I’ve long favored GR as likely the more correct theory over QM. The former is a singular coherent physical vision that makes sense. The latter is, as Richard Feynman famously said, something no one comprehends.
¶ Writing about the “quantum leaps” of the electron: “Its as if God had not designed reality with a line that was heavily scored but just dotted it with a faint outline.” For a theoretical physicist Rovelli invokes God quite a bit (not that I’m complaining; far from it).
Another one: “The beautiful theory, SU(5), despite its considerable elegance, was not to the good Lord’s liking.” (Apparently, late in life, Einstein’s belief in Spinoza’s god gained an anthropomorphic aspect. Einstein would refer to bad theories as “sins” against god.)
Rovelli also writes about stars in the “heavens” which I found rather poetic, but you see what I mean about baroque?
¶ Speaking of which, here’s another example: “Here, in the vanguard, beyond the borders of knowledge, science becomes even more beautiful — incandescent in the forge of nascent ideas, of intuitions, of attempts. Of roads taken and then abandoned, of enthusiasms. In the effort to imagine what has not yet been imagined.”
Incandescent forge, wow! Again, I’m not really objecting. It’s just slightly bemusing language to run into in a physics book. It may be that Latin culture is so much more supportive of expressive comportment. Part of me thinks it’s kinda cool, but style is also a distraction.
¶ It’s funny how I don’t agree with Rovelli at all when it comes to time or the idea that reality is mainly relationships, but I do quite agree with him on other points.
For instance: “I believe that our species will not last long. It does not seem to be made of the stuff that has allowed the turtle, for example, to continue to exist more or less unchanged for hundreds of millions of years, for hundreds of times longer, that is, than we have even been in existence.”
I have expressed similar sentiments on this blog.
¶ Lastly, a footnote in the longer book caught my eye:
“This cloud is described by a mathematical object called “wave function.” The Austrian physicist Erwin Schrödinger has written an equation describing its evolution in time. Quantum mechanics is often mistakenly identified with this equation. Schrödinger had hopes that the “wave” could be used to explain the oddities of quantum theory: from those of the sea to electromagnetic ones, waves are something we understand well. Even today some physicists try to understand quantum mechanics by thinking that reality is the Schrödinger’s wave. But Heisenberg and Dirac understood at once that this would not do. To view Schrödinger’s wave as something real is to give it too much weight — it doesn’t help us to understand the theory; on the contrary, it leads to greater confusion. Except for special cases, the Schrödinger’s wave is not in physical space, and this divests it of all its intuitive character. But the main reason why Schrödinger’s wave is a bad image of reality is the fact that when a particle collides with something else, it is always at a point: it is never spread out in space like a wave. If we conceive an electron as a wave, we get in trouble explaining how this wave instantly concentrates to a point at each collision. Schrödinger’s wave is not a useful representation of reality: it is an aid to calculation that permits us to predict with some degree of precision where the electron will reappear. The reality of the electron is not a wave: it is how it manifests itself in interactions, like the man who appeared in the pools of lamplight, while the young Heisenberg wandered pensively in the Copenhagen night.”
That’s how I see it as well. Rovelli doesn’t seem down with MWI. Other than this footnote, it’s not mentioned at all. (He doesn’t talk much about Schrödinger, either. I believe this footnote is the only time he’s mentioned.)
The other thing I found kind of charming in the longer book is how much Rovelli brings in various Italians in history, often awarding them high credit as scientific thinkers.
For instance, he has Dante using 3-spheres in his cosmology in Paradiso.
Stay safe, my friends! Go forth and spread beauty and light.
October 12th, 2020 at 10:09 am
Rovelli has an interesting diagram that he’s been building progressively during the trip through history:
It’s kind of a neat way to visualize how our view has changed. It also shows, at the bottom, how our view of reality has boiled down to two theories that both make astonishingly accurate predictions in their domain, but which are at odds with each other.
October 12th, 2020 at 11:01 am
Rovelli, pointing out the humbleness of truly great minds, uses a great phrase: “Genius hesitates.” We see that over and over in the history of science.
October 12th, 2020 at 11:03 am
Rovelli also makes some interesting points about how our intuitions can both inspire us and mislead us. Many of the greatest insights in science come from (informed) intuitions. And so do some of its greatest mistakes!
October 12th, 2020 at 11:09 am
A very good example of an intuitive mistake might be SUSY, which stubbornly refuses to present any experimental evidence whatsoever.
Along similar lines Triton Station just put up a great post summarizing the search for Dark Matter WIMPs.
October 12th, 2020 at 3:33 pm
I read Seven Brief Lessons a while back and was underwhelmed. It seemed very basic, and I felt robbed. It’s made me leery of Rovelli’s other stuff.
He does come up with interesting ideas. Personally, I’m open to anything being emergent, including space and time, but to buy it, I need a clear account of how it emerges, of how our experience of it, including scientific measurements of it, are produced in that emergence.
On the wave function, if the wave isn’t something physical, then I wonder what causes the interference effects. And quantum computation seems to be getting a lot of work out of a mathematical contrivance. Does Rovelli address these issues anywhere?
October 12th, 2020 at 4:07 pm
I’m not blown away by Rovelli, either. (You’re not the audience for Seven Brief Lessons, either! I think it started as a series of newspaper or magazine articles.)
I do like some of what he says (as noted in some comment above and in the post), but overall I’ll stick with someone I see as less of a space cadet.
“On the wave function, if the wave isn’t something physical, then I wonder what causes the interference effects.”
That is definitely a question in terms of the physicality of it. (Rovelli doesn’t get into these aspects at all. His only mention of MWI is in that footnote, and he never gets into superposition or decoherence that I’ve seen. He even seems to prefer Heisenberg’s QM over Schrödinger’s. The former is mentioned often, but the later rarely. Again, mainly in that footnote.)
As I keep saying, I think understanding the physicality of superposition is a major key to progress in QM.
As I’ve also said, I’m not convinced MWI addresses superposition other than what seems like a hand-wave that in some cases, for some reason separate worlds interfere in ways we easily detect.
In the two-slit experiment, I can see how MWI might branch on where specific photons land, but I don’t understand the story MWI tells about interference any more than I do the physicality required for the CI story. Superposition is weird!
Qbits, likewise, are superposed weirdlings!
October 12th, 2020 at 5:04 pm
The MWI is not the only interpretation that takes the wave function to model something physical. Pilot-wave, the ones arguing consciousness causes the collapse, objective collapse theories, and something called the Transactional Interpretation do as well.
October 12th, 2020 at 9:01 pm
“The MWI is not the only interpretation that takes the wave function to model something physical.”
Depending on one’s definition of “model” they all do! 🙂
As Rovelli points out, the Schrödinger equation, as an object, lives in Hilbert space, which isn’t physical (any more than phase spaces are in classical mechanics — kind of the same thing, really). This is why I think it’s good to separate the Schrödinger equation from the physicality of what might be happening.
FWIW, I’ve been speculating. You’ve seen my Wave-Function Story post, but after our recent discussions of MWI it might be more relevant. (I noticed in the comments I mentioned Everett and memory.)
October 13th, 2020 at 8:56 am
Rovelli’s comments echo the sentiments of Heisenberg, Born, and many others in the Copenhagen camp. Yet I’m struck by the fact that Schrodinger himself never agreed with it. His original motivations when developing his equation were to model the physics, and he never seemed to agree with the idea that it was only abstract. (He actually may have described something like the Everettian view in a talk a few years before Everett’s thesis.)
Maybe the reality is that it’s a mix, with portions being abstract and other corresponding to reality. Whatever the case, the dynamics appear to have too much causal effects for me to see it plausible that it’s all just a mathematical tool.
October 13th, 2020 at 2:54 pm
It’s true that Schrödinger (and Einstein) didn’t care for certain aspects of QM. They were both fundamentally realists — Einstein especially so. I think it might be going a bit far to put Schrödinger in the MWI camp, though. (For one thing, there really wasn’t such a camp until 1972 when DeWitt took up MWI and added decoherence.)
That book from the previous post didn’t mention it except very briefly. I was sort of looking for it, because I know MWI proponents hold up that bit of his, but it’s possible there’s a bit of wishful thinking involved.
I believe that ultimately Schrödinger came to accept Born’s view that the equation, when solved, returns an amplitude, and the norm squared of that amplitude is the probability of getting that measurement.
As for it being a mathematical tool (only), the relationship seems to be similar to, for example, orbital dynamics. We have mathematical tools that let us make extremely accurate predictions about orbital mechanics. The question is whether the math is just a description or somehow represents actual reality. The latter raises the issue of just how that math is reified.
My sense is that all of our mathematics, from start to finish, is just description. The physical world interacts according to physical rules that are consistent and therefore can be described (in various ways) with math. But they’re not the same thing. (Unless Tegmark is right.)
October 13th, 2020 at 5:50 pm
On Schrodinger, yeah, it all involves a purported talk he gave in 1952 in Dublin. But apparently it’s all based on people’s memories, so who knows. But plenty of sources indicate he held to the ontic view of the wave throughout his life. I’m sure he did except the Born rule as a mapping to experimental results. Given the evidence, it would have been silly not to. But I can’t recall seeing anything where he ever accepted the ontological role Heisenberg, Bohr, and Borne relegated his equation into.
I don’t think Tegmark is right. There is lots of math which isn’t reality. And there’s no guarantee the current equations capture the full reality. Who knows what we might learn in the future? But the evidence seems to indicate that the QM math accurately captures at least a subset of that reality. The question is whether anything interrupts the dynamics modeled by that math.
October 13th, 2020 at 7:57 pm
(I think you mean the epistemic view of Heisenberg, Bohr, and Born?) Yes, I agree. Einstein and Schrödinger were both staunch realists and figured something real had to be there.
“But the evidence seems to indicate that the QM math accurately captures at least a subset of that reality.”
Absolutely. The question is what is captured. Is it, as with orbital dynamics, just a model that’s useful for prediction? Or is it reified and taken as a literal object?
What seems to point strongly to the first option is that the Schrödinger equation, when solved, just gives predictions. Pointing away from the second option is that the equation uses complex numbers and exists in Hilbert space.
(An aside: Funny irony to me is that MWI makes a parsimony claim on removing collapse, but to me the consequences of the view make it overly baroque and complicated. I end up seeing the CI as the simpler version given I accept non-locality. Go figure. 😀 )
October 13th, 2020 at 9:18 pm
The thing to remember about MWI’s parsimony claim is it pertains to assumptions. Its assumption is that the mathematics of QM model something real.
The collapse postulate may seem simple on the face of it, but all the paradoxes in QM seem to come in because of it. MWI provides an explanation for the appearance of the collapse, via the same mechanics as in the rest of QM. A real explanation is going to be more complex than an ad hoc kludge, which is what the collapse amounts to. I’m not saying the collapse postulate wasn’t a reasonable move, in 1927, but the ongoing attachment to it is, I think, hampering progress.
October 14th, 2020 at 12:58 am
“The thing to remember about MWI’s parsimony claim…”
I remember. I’ve never found it a compelling argument because I don’t think we can separate axioms and consequences. To me a theory is responsible for both.
“The collapse postulate may seem simple on the face of it, but all the paradoxes in QM seem to come in because of it.”
All the paradoxes? We’ve discussed two: non-locality and randomness. They are definitely open questions. But I’ve given possible physical accounts for both and made strong arguments towards their physicality. Neither cause violations in physical laws, but we don’t have a theory explaining them. Contrast that with the energy and physical coincidence issues of MWI, and it’s at least a draw.
“I’m not saying the collapse postulate wasn’t a reasonable move, in 1927, but the ongoing attachment to it is, I think, hampering progress.”
Is it? Can you point to examples?
I think it’s a matter of understanding collapse. As I’ve said, I think the answer lies in understanding superposition and the quantum/macro divide. Those are both things we actually observe. I think we need to fully understand them. Measurement, I believe, is just what happens when those two interact. (The macro world is bigger, so it always wins.)
October 14th, 2020 at 9:37 am
On paradoxes, wave/particle duality, Schrodinger’s Cat / Wigner’s friend issues, and everything else I commonly see hand wringing about all seem related to the collapse postulate.
You gave plausible physical accounts for randomness and non-locality? I must have missed that. (Or don’t recall it being as plausible as you do.) Typically, they seem to just be accepted as brute facts. Again, I have no issue with them being accepted as brute empirical facts, or even as placeholder constructs in an instrumental theory, but observations always require interpretation, and assuming that we will never find a more logical interpretation strikes me as problematic.
On hampering progress, I suspect if the particle physics community hadn’t closed itself into a dogmatic loop on quantum foundations in the 1930s, we would have seen progress on other interpretations, decoherence, and the EPR paradox much sooner. People often dismiss interpretations (which are really alternate theories) as metaphysical navel gazing, but it may well turn out to be necessary for quantum gravity.
October 14th, 2020 at 10:46 am
“…all [paradoxes] seem related to the collapse postulate.”
I agree it’s an open question. (As I’ve said, I don’t think it’s the central problem. Superposition and the quantum/macro divide are what I see as the burning issues.)
“You gave plausible physical accounts for randomness and non-locality? I must have missed that.”
I have an impression you don’t take me very seriously and therefore don’t pay that much attention to what I say. There have been times, after we’ve debated a topic, I’ve realized you don’t seem to have absorbed what I’ve said. (To be clear, I’m not at all talking about agreement. I’m talking about knowing exactly what my argument is.)
Fairly recently there are two posts, Wave-Function Collapse and Wave-Function Story that give my account of some possibilities. More recently, this comment on the post where you, Michael, and I, were discussing MWI, explains why I see non-locality as a reasonable axiom. I’ve also touched on it in numerous comments.
The TL;DR is both may be axiomatic — just how reality is — and I’m fine with that because I like the idea of some randomness and non-locality can emerge from theories with more dimensions than three (which doesn’t seem like a big ask to me). Non-axiomatic randomness might be due to the interactions in the wave-function — stuff at the Planck level we’re not able to probe yet — that determine which “particles” interact. Non-locality may be tied to the dimensions of spacetime being more than four, which makes it physical, but still axiomatic.
“…and assuming that we will never find a more logical interpretation strikes me as problematic.”
Well, sure, but no one here is making that assumption. 🙂
“On hampering progress,…”
Maybe. Hard to say. There are always iconoclasts with ideas outside the mainstream. Those with genuinely useful ideas, those ideas tend to persist. I’m not one who thinks things are forever lost. “Science proceeds despite scientists.” (On some level, it’s a Platonic view. Stuff is out there to be discovered.)
One problem is the crackpots by far outweigh those outliers with good ideas, so the filter does need to be restrictive or science would be flooded with bad ideas. (It’s the old false-negative, false-positive issue.)
As you’ve pointed out, if either side had a real winning card, they’d play it. As I’ve said before, it’s really annoying having two great hugely tested theories that definitely both can’t be right and very likely are both wrong or incomplete in some way.
As I’ve said here, GR feels more sensible, physical, and intuitive, to me, whereas QM is kind of a weird hot mess that no one understands. We don’t argue about interpretations of GR because it is so simple and sensible. QM, on the other hand, has entered the domains of metaphysics and philosophy. (Kind of like the study of consciousness and for similar reasons.)
October 14th, 2020 at 12:13 pm
One of the things I’ve had to come to term with over the years is that nobody ever reads my stuff as closely as I’d hope. No one ever parses it as carefully as I crafted it. I take you as seriously as I take anyone I have regular conversations with. But I’ll never take your writing as seriously as you take it. And I’m pretty sure you’ll never take mine as seriously as I take it. It means we’ll periodically have to repeat stuff to each other we already said a while back. The human condition.
On preferring a universe with randomness and non-locality, I get that. I read somewhere that one of the Copenhagenists said something similar to either Einstein or Schrodinger, wondering why they were so hung up on determinism, that they themselves actually preferred a reality with some randomness.
Myself, I want a universe that can be understood. Randomness and unexplained non-locality, represent things we don’t understand. Many people love mysteries in and of themselves. I only love them as problems to be solved. (Which is why I typically hate fiction that introduces mysteries with no solution.)
The reason the MWI appeals to me is it explains the randomness and apparent non-locality, and all its dynamics, at least to me, seem understandable. I assess it on its economy of assumptions and testable predictions. The untestable ones, while incredible, seem irrelevant from a scientific assessment; it’s very possible unknown factors prevent their full realization.
Doesn’t mean it’s right, or even if it is, that it’s completely right. As I noted before, if it is right, I suspect it’s right in the same way Copernicanism was right in 1543, that is, with a lot of misconceptions still baked in and many paradigm shifts left to go.
October 14th, 2020 at 3:56 pm
“And I’m pretty sure you’ll never take mine as seriously as I take it.”
You have to speak for yourself only here. I take your ideas quite seriously. Specifically, I think I have a good understanding of what they are.
“Myself, I want a universe that can be understood.”
I doubt you’re alone in that!
As you know, it (probably!) can’t be turtles all the way down, so something is axiomatic. Our philosophical and analytical views obviously have an impact on what we find reasonable and sensible for that role.
October 13th, 2020 at 7:04 pm
My problem with relationship-based views is that, by definition, a relationship is between t[w]o things. Without the things, there is no relationship.
Is this true? Are there actually any “things” at the end of the day? If the Buddhists are right there are no things whatsoever that exist in the absence of relationships. There are no “things” at all. My take on this is that what we call a “thing” is just a stable or repeating, but dynamic form of relationship.
The division of perfect stillness into a wave instantly involves two poles, which are related. No?
To say it another way, I can’t see how the illusion of “things” can occur without the relationships of which they are comprised.
I think of Mach’s Principle when this comes up, and how certain properties of “things” could be the sum total of relationships throughout the universe (for instance).
October 13th, 2020 at 8:12 pm
“Is this true? Are there actually any ‘things’ at the end of the day?”
In the world of physics, I’d have to say yes, but I think you’re speaking of something else.
FWIW, I’m not saying relationships don’t exist, or even that the world could make sense without them (I don’t think it could). I am saying ‘things’ are fundamental while relationships are consequential. (But that’s just my view of the horse and cart. I’m a physical and philosophical realist.)
“My take on this is that what we call a ‘thing’ is just a stable or repeating, but dynamic form of relationship.”
Can you give me an example?
“The division of perfect stillness into a wave instantly involves two poles, which are related. No?”
I don’t know what that means, so I have no idea!
“To say it another way, I can’t see how the illusion of ‘things’ can occur without the relationships of which they are comprised. “
You got me on that one, too. You seem here to start on the premise ‘things’ are an illusion. And assuming ‘things’ are comprised of relationships. What if things are real (and fundamental) and relationships are consequences of the properties of things?
But I’m afraid I’m still not really following your point. 😦
On some counts I’m kind of slow. I need concrete examples of things.
October 13th, 2020 at 8:13 pm
“…concrete examples of things.”
😀 As they say on Archer: “Phrasing!”
October 14th, 2020 at 1:13 am
Actually, strike the part about “physical and philosophical realist” — one could hold that relationships are both primary and physical, so the stance is irrelevant here.
October 14th, 2020 at 6:12 pm
Can you give me an example?
Well, an electron, I think. Or an atom. I think these so-called “things” are vibrating energy fields at the end of the day. And a repeating vibration like this is in essence a repeating exchange between two polarities: a plus and a minus, a yin and a yang, a vacuous energy field or a compressed material particle, however you wish to define the two poles of the vibration.
You seem here to start on the premise ‘things’ are an illusion. And assuming ‘things’ are comprised of relationships. What if things are real (and fundamental) and relationships are consequences of the properties of things?
Certainly this could be argued as a matter of perspective, but I cannot think of any “thing” that is not itself a dynamic system. The difficulty I have with things is that by and large what we think of as “things” are in essence stable, repeating dynamics. And I don’t tend to equate the word “thing” with a repeating dynamic pattern.
I certainly can understand that one could argue both sides of this–that relationship is fundamental or that things are fundamental–but to argue that “things” are fundamental I think is a macroscopic view. It’s our intuition from working on a macroscopic plane through most of our perceptions.
I wrote, The division of perfect stillness into a wave instantly involves two poles, which are related.
This is probably not something I can explain easily, but I’m intrigued by the view that suggests the sum total of forces in the universe adds up to zero, and that for every plus there’s a minus at some level. And since everything is dynamic, I’m saying that everything is (the turtle at the bottom of the pile) the division of stillness-balance into a plus and a minus. But because the plus and the minus both emerged from a common beginning of “zero” they are related. They ARE a relationship.
I suppose an example could be down conversion of an electron into a pair of photons. But I’m speaking of something that is a general dynamic and may occur at arguably every level of scale–think of a rubber band or a spring for instance–and that probably “begins” at some fundamental level as a smallest unit possible of plus/minus. These would be the vacuum fluctuations, perhaps…
October 14th, 2020 at 8:07 pm
“I don’t tend to equate the word ‘thing’ with a repeating dynamic pattern.”
Ah, okay. That would definitely have an impact on what you view as ‘things’.
(In contrast, I see a ‘thing’ is almost anything I can give an identity to. An electron, certainly, but also a song, a musical note, a nice breeze, a bad idea, the number π, a year, and my “thing” for caramel.)
“Well, an electron, I think. Or an atom. I think these so-called ‘things’ are vibrating energy fields at the end of the day.”
Totally, and if you don’t see dynamical systems as ‘things’, I can see why you wouldn’t think much of anything was a ‘thing’. (Question: an electron is a soliton-like wave packet in the electron field. Is the field a ‘thing’?)
I see how you’re using poles now, and I can’t help but approve, since I see Yin-Yang as a fundamental facet of reality. (I love that duality is itself dual in that some opposing pairs are true opposites — plus/minus charge, for instance (or male and female) — but others are something and the lack of it — hot/cold and light/dark, for instance. I call the latter type “cup” pairs, as in empty and full cup.)
One observation I make about poles is that they’re conceptual and abstract — nothing is ever pure pole, so to speak. (The small dots of opposing color in the Yin-Yang symbol are making a similar statement.) The North Pole is my canonical example. You can put your foot on the North Pole, but every atom in your foot is still actually some tiny distance south of the Pole. The NP itself is an abstract concept (a literal singularity in the map) with zero dimension and zero extent.
(In the same sense all humans are somewhere between the NP and SP, if we see poles of Good and Evil, so, too, are all humans somewhere between them.)
“Certainly this could be argued as a matter of perspective, but I cannot think of any ‘thing’ that is not itself a dynamic system.”
Totally agree! Our membership function for ‘thing’ differs, so such systems are ‘things’ to me.
I think why I see relationships as emergent and consequential is because with self-contained dynamical systems, such as electrons, atoms, even people, the relationships of the dynamics seem to me self-contained. However there is definitely, as you say, a macro-level view to this.
For example, An atom is a ‘thing’ with distinct properties, but is comprised of parts with internal relationships. Zoom in to an electron, and it’s a ‘thing’ with distinct properties, but is comprised of waves in a field. Zoom in again to a single part of that wave packet (I’m not sure how possible that is), and one might call that a relationship between time and energy on that field.
Maybe for me the level of the view is important. When looking at atoms as atoms, I don’t care about the parts, so I see a distinct ‘thing’. To me, relationships at that level pertain to relationships between atoms, and I see those as emergent. OTOH, if I’m dealing with electrons or quarks, I again see relationships between particles as emergent. The same would apply at the wave-packet level.
“But because the plus and the minus both emerged from a common beginning of ‘zero’ they are related. They ARE a relationship.”
Okay, but if plus and minus both emerged from ‘zero’, doesn’t the relationship begin with the ‘thing’ zero? And then the ‘things’ plus and minus that are the terminal points of any relationships?
It reminds me of the definition of the natural numbers:  the number
zero;  a “successor” function,
S(x), that returns x+1.
To some extent, the second part is a relationship (although it’s predicated on the axiomatic ‘thing’
one), so that’s a built in part of the natural numbers, but it starts with the ‘thing’
In the end, maybe we just use different labels for the same thing. Or ‘thing’. 🙂
October 17th, 2020 at 3:49 pm
A bookmark: Just read an article in phys.org, “Could Schrödinger’s cat exist in real life? Our research may soon provide the answer” about an idea for a test of quantum superposition that might provide a clue about the divide between the quantum world and the macro world.
I’m not familiar with the heat dynamic they talk about, but I have heard of back action (I believe Sabine Hossenfelder’s blog is named after it).
Here’s a central quote:
If such heat is found, this implies large-scale quantum superposition is impossible. If such heat is ruled out, then it’s likely nature doesn’t mind “being quantum” at any size.
Which, huh, lies very much at what I think is the heart of the question.
I was also struck by the line:
We would also need to keep an effect called quantum “backaction” in check, in which the act of observing itself creates heat.
Which might be a definitive answer to the measurement problem.
The authors of the proposed test say a working experiment is years of development and millions of dollars away, but, if their ideas are correct, might indeed give us some long-sought answers.
Would be exciting to think so.
October 18th, 2020 at 5:12 pm
I need to finish this book and return it because the library is piling on. A bunch of books I had on hold because available early.
So now I have three weeks to get through: The Sellout (Paul Beatty), The Long Way to a Small, Angry Planet (Becky Chambers), and an Agatha Christie Poirot book (Mystery on the Blue Train).
On top of that, it’s the Baseball World Series starting Tuesday.
I definitely won’t do a write up of Rovelli’s book. All the Loop Quantum Gravity stuff is hand-waving and nothing I haven’t already read about LQG. The book is oriented on those with a causal interest, so it doesn’t get in depth. I’ve liked it better than the other two of his I’ve read, but I think it’s safe to say I’m not much a fan or his writing or ideas.
October 20th, 2020 at 12:57 pm
Finished the Rovelli book. Skimmed through the last chapters, but didn’t find anything more than I was expecting.
Started a book about “The Calculus” by David Berlinski, the second book of his I’ve tried. Gave up after a couple of chapters. Berlinski is also not my cup of tea — talk about baroque writing, sheeze. Based on those two books, neither of which I could finish, I’m definitely also not a fan of Berlinski. Lesson learned.
OTOH, I’m now reading Paradox: The Nine Greatest Enigmas in Physics by Jim Al-Khalili and quite enjoying it.
October 23rd, 2020 at 9:14 am
One question I’m hoping my studies into the math of QM will answer involves the description of a beam-splitter experiment. Crucially, when and where does the superposition occur?
A) The superposition starts at the laser and describes the full flight of two photons, one of which is reflected by the mirror, one of which passes through it.
B) The superposition starts at the mirror where the quantum interaction responsible for the branch is.
My question is about the nature of the description before the mirror.
A casual reading of Everett suggests [B], but the more I think about it, the more it seems [A] might be the way it is.
Combined with the idea of a universal wave-function, it seems to lead to the view that each superposition of the universal wave-function must describe an entire universe. What appear to be branches are just points where two wave-functions (which have been identical so far) finally diverge.
It’s the same thing as two descriptions of the photon being identical up to the mirror and then then diverging. The premise of universal wave-function expands the beam-splitter wave-function to the world’s wave-function, so beam-splitter experiments are really just places where the wave-functions of two formerly identical worlds finally diverge.
Assuming that’s correct, one can rescue locality without resorting to contortions about light cones having to coherently merge or not merge when it comes to Alex and Blair experiments involving fully entangled particles.
If they do a single experiment, there are only two worlds involved, the [A-Up]+[B-Dn] world and the [A-Dn]+[B-Up] world. The universal wave-function has a superposition of these two worlds, and that superposition is identical up to the experiment. It then diverges into the two worlds just noted.
This also deals with S.R. issues, since it makes no difference what order Alex and Blair perform the test, and it makes no difference to passing observers. Everyone is, and always has been, in the appropriate branch to make the observation they make.
It does make the universe — all worlds in it — fully deterministic because the wave-function is fully deterministic. The wave-function describing a single world necessarily describes it from start to finish.