Mindscape 241 | Tim Maudlin on Locality, Hidden Variables, and Quantum Foundations

[@michaelberg7201]

This has to be one of the best Mindscape podcasts yet. What a privilege it is to be able to listen in on a dialog between Tim Maudlin and Sean M. Carroll about the most foundational aspects of the universe and the physics that govern it. Tim and Sean are two incredibly charismatic communicators who seem to enjoy each others company as much as the subject matter itself. Truly inspirational to listen to. Dunno if you're reading this Sean, but thanks so much for making and sharing this podcast for free here on KZbin. Looking forward to the next episode!

[@wgcar]

I believe this is the best Sean Carroll podcast ever published. Not only because of his guest but from Sean himself. More natural,not mannered or vaguely scripted. Somehow this should be “pinned” or otherwise promoted so all Sean Carroll’s fans are encouraged to listen in.

[@techteampxla2950]

Prof. Sean and Tim is a gift 🎁 to the universe

[@Zen_Cycling]

agreed, breath of fresh air

[@aqu9923]

Intellectual honesty of Tim makes me a better human!

[@jlcapshaw]

Tim and Sean are among the most articulate and clear minded professionals enabling non-professionals to have some semblance of understanding of foundations of physics.

[@schmetterling4477]

They are also both completely wrong. ;-)

[@wiesawnykiel1348]

@@schmetterling4477 They are both very interesting thinkers, but I think they bet on bad horses. The many worlds interpretation was created mainly to question the existence of the collapse of the wave function (and who has ever seen functions - mathematical entities - collapse) and Bohm's interpretation - I think - can be falsified.

[@schmetterling4477]

@@wiesawnykiel1348 You can find the problem with MWI in the second sentence of Everett's thesis: he believed that the wave function is a description of the individual system. That's completely false, of course. The wave function is a description of the unmeasured quantum mechanical ensemble. Having mistaken the entire forest for the falling tree, Everett than proceeds to calculate that every single falling tree generates an infinite forest's worth of wood. It's a totally trivial accounting error. The man couldn't count.. not even to one. ;-)

[@neildutoit5177]

​@@schmetterling4477who do you recommend? Who do you think is right?

[@schmetterling4477]

@@neildutoit5177 Copenhagen is 100% correct, but it's not easy to figure out why that is so. Now there is an actual educational problem. If you read the literature, then you will find that foundational issues are rarely handled well in standard textbooks. They explain well how the theory works, but not where the math of the theory comes from. One can find bits and pieces of the "where" and "why" in the early papers, e.g. in Heisenberg's matrix mechanics papers and in von Neumann's quantum mechanics textbook, but I find it quite hard to piece it together that way. Then there are a few papers that I have seen in the past that basically derive the formalism of quantum mechanics from first principles starting with Kolmogorov's axioms. At some point one will have to insert relativity into the derivation to connect the math unambiguously to actual physics, but I have not seen any publication that does that in a straight forward deductive way. The relativistic theory is almost exclusively treated on its own in field theory books that already assume that the reader is familiar with the formalism. My intuition about it comes mostly from the lab. I am a high energy physicist, so I have hands on experience with quantum measurements. I could personally not make any sense of the theory until I became focused on high energy physics detector design. Once I had the experience of what it actually means to make a quantum measurement the different disjoint pieces (Heisenberg, Schroedinger, quantum field theory) began to come together, but that might be a consequence of me not being good with theory and math in general. Better physicists than me can probably make sense of it all without actually looking at tracks and detector hits all day long. So, yeah, I can't really give you a good reference. I used to accuse von Neumann for messing this up because of his very theory heavy textbook about QM, but eventually I got all the way to chapter six, I believe, and in there he actually demonstrates that he fully understood how an individual quantum measurement works and how that leads to the structure of the theory. He just didn't care much about flashing it out and most professors who teach QM probably never even read that chapter in that book. Newer books, OTOH, often completely exclude the material in there because it is not directly relevant to the average student's practical needs. The "shut up and calculate" mentality is, IMHO, mostly driven by the fact that in a four year physics program students only take two highly compressed theoretical QM courses. The first one is an introduction to non-relativistic quantum mechanics that is centered on the Schroedinger equation... which is the worst way to learn about foundational issues because it is usually presented in a spatial basis and the last thing nature cares about are spatial wave functions (energy and momentum are conserved, position is not). The second one is a very quick hush-hush introduction to relativistic theory and maybe QED. In mine central issues like renormalization were given like ten minutes... which kind of tells you that there is simply not enough time for a really deep treatment of QM and field theory in an undergrad setting. Sorry about the rant. You can probably feel my own frustration with the lack of availability of comprehensive foundational materials on QM.

[@bia10]

I rarely comment on KZbin, but this was brilliant, many host are good but this is far beyond good. Could we see some other brilliant people like this, David Deutsch please?

[@modalsurrealist]

Is it tho?

[@vogarner]

​@@modalsurrealist What motivates someone to post a comment like this? The op stated their opinion that the discussion was brilliant. If you think it was so bad that you have to make it known how much you disagree, why not say why? Otherwise you're basically just signalling that you didn't get anything out of it and seeing that someone else did, you feel inadequate.

[@modalsurrealist]

@vogarner I'm sorry. Full honesty. I didn't realize. Thank you for calling me out on it.

[@princesizwe2952]

@@modalsurrealist that's amazing you recognized being called out. Bravo that is brilliant of you.

[@ВоваБулатов-я6л]

😮😅😅😅😮😅😮😅😮😅😅😮😅😮😅😮😅😅😮😅

[@jayarava]

Talking about difficult stuff, without talking bullshit. The world needs more of this.

[@schmetterling4477]

MWI is bullshit. ;-)

[@jonfrankle]

Simply awesome conversation. I just went back to re-listen on Google podcasts, which apparently will be migrating into KZbin before long. Tim has such a gift to accurately lay out the top alternative interpretations of quantum mechanics so clearly; credit to Sean for steering the discussion.

[@mylittleelectron6606]

I haven't heard Tim say, "That's a great question..." so many times during an interview. I really hope the Jon Bell Institute receives the funding it needs and deserves.

[@edwardhammond8778]

For years I have found no public intellectual who could match the depth, breadth, and human character of Sean Carroll. Someone who I both know could convince me of anything, but with the intellectual integrity never to attempt to do so even by accident. After listening to Tim, I think my list has officially increased by one. Thinking about it, David Albert should be on that list too. Philosopher-physicists all of them, I wonder if that's a coincidence.

[@davidlewis5737]

There are impressive people in philosophy departments. Tim is a philosophers philosopher

[@snarkyboojum]

David Deutsch is well and truly up there.

[@robocop30301]

I've been waiting for this for so long! Thanks for making it a reality!

[@aanchaallllllll]

0:00: 🎙 Tim Walden discusses the importance of foundations of physics and the sociological reasons for its lack of popularity among physicists. 9:33: 🔬 The discussion revolves around the mysteries and challenges of quantum mechanics. 18:53: 🔬 The speaker discusses different interpretations of quantum mechanics, including the many worlds theory and the collapse theory. 27:41: 🧪 The non-relativistic theory of quantum mechanics involves the addition of particles to the wave function, which guides their behavior. 36:54: 🔬 The discussion highlights the development and challenges of the guidance equation theory and the introduction of hidden variables in quantum mechanics. 46:11: 🔬 The pilot wave theory in quantum mechanics suggests the possibility of faster-than-light signaling through spin dependence of arrival times. 55:09: 🔬 The discussion explores the challenges and different approaches in understanding quantum mechanics, including the pilot wave theory and the concept of particle creation and annihilation. 1:04:06: 🔬 The speaker discusses the importance of the Higgs boson in explaining observable properties and the need for experiments to test different theories. 1:15:39: 🧠 The discussion revolves around the relationship between metaphysics and physics, and the different approaches taken by philosophers in understanding reality. 1:21:59: 🕰 The directionality of time is a hotly contested topic among philosophers and physicists, but the existence of temporal asymmetries suggests that time has a direction. 1:30:44: 💡 The speaker discusses the dangers of being too easily satisfied or too stubborn in one's beliefs, and emphasizes the importance of finding a reasonable place to stop in the pursuit of knowledge. Recap by Tammy AI

[@junomanfx]

Fantastic. I could have listened to 10 more hours of that.

[@catherinegrimes2308]

Thank you for hosting this podcast, I really enjoyed it. I was shocked to hear that professional academic physicists don't like people asking questions and such people have to work in philosophy departments. Several years ago, I watched a KZbin video that was filmed at Nottingham University with the presenter essentially saying that quantum mechanics is an embarrassment. When I was doing an MSc at Nottingham, the physics department was in favour of string theory whereas the mathematics department was against it. I don't think that these attitudes are conducive to progressing science, no wonder we have made such little progress on the nature of matter. My background is engineering and hearing physicists make great claims for their theories where there is no mechanistic explanation leaves me less than satisfied. To me it is like Newton's 2nd Law before there was an explanation of inertia, the equations worked very well but people couldn't explain why. This "shut up and calculate" attitude has caused a lot of damage and I wish that there were proper funding for other theories such as the De Broglie-Bohm theory.

[@HelsinkiFINketeli_berlin_com]

Catherine, that's how it is and that's a one reason why Heidegger said that science doesn't think.

[@SlimThrull]

Asking questions is always dangerous. While the scientific method is generally pretty sound, humans and their dogma are not. It may surprise you to learn that Einstein was outright mocked for his ideas on how space-time worked. I believe is ideas were called something like, "Totally impractical and absurd!" Science has always worked this way. New ideas that fly in the face of dogma are generally not well received.

[@patrickirwin3662]

Like many here, grateful finally to see this long hoped-for interview. Thank you.

[@MarcelBlattner]

This interview is amazing. And on top it is entertaining. You should do a follow up!

[@Albeit_Jordan]

This is a favorite podcast ep of mine to repeatedly return to, rich for relistens when you want something on in the background.

[@ShaunaCarpenter-e1b]

TY Sean, for your probing yet succinct-interviewer style. For a lit major, another talk that fills in the many black holes of my learning with trenchant explanations.

[@DestroManiak]

Very excited for this one. When it comes to interpretations of quantum mechanics, I am an extremist. I flip back and forth between many worlds and hidden variables. I like these two because it dissolves the problem of "ontological randomness" and reduces it to "epistemic randomness"

[@dimitrispapadimitriou5622]

Well, there's no "problem" of ontological randomness. On the contrary, some irreducible stochasticity might be crucial for our theoretical models to correctly approximate the real world. Strict determinism is good for toy models, but not so for an immensely complicated physical Universe. Anyway, fundamental stochasticity is only a "problem" if we're adopting certain philosophical prejudices.

[@CurtOntheRadio]

What does that mean, please?

[@dimitrispapadimitriou5622]

@@brothermine2292 There's a well known old joke, with a furious wife entering her house's bedroom , finding her husband with another gal..." No, wait darling, this is not what you're thinking..." says he... Exactly the same happens with people adopting "Many Worlds" or "Pilot Wave" theories, or even worse, superdeterminism, just because they don't like what they're seeing with their own eyes : That a quantum measurement has a definite single outcome that by itself is merely stochastic, governed by the Born rule probabilities. Even in the case of MWI, not even the "Everettian Demon " himself ( the MW analogue of the proverbial "Laplace's Demon") could inform an experimentalist about the outcome of an oncoming measurement - not even in principle , as we all know...the same with Bohmian mechanics: it's impossible, in principle, to know beforehand the outcome of a single measurement, generically. So, what's all this fuss about? Just because we like determinism ( for some ill defined "reasons"?), or we like the ( naïve) idea of the "block universe"? Or because we feel insecure with randomness ( although this Quantum kind of randomness is not of the kind that "everything goes", it's governed by probability, so, what?

[@bobross7005]

@@dimitrispapadimitriou5622true, but they’re prejudices that result from macroscopic physical experience universally lol.

[@dimitrispapadimitriou5622]

@@bobross7005 Well, exactly, empirical experience strongly suggests that the laws of Physics are fundamentally Probabilistic. So, what's your point? We are in agreement, no?...

[@QuicksilverSG]

This was a great conversion by two scientists who made genuine efforts to listen to each other and find points of mutual agreement, rather than focus on contentious points of debate. What it brought out is that Bohmian Mechanics and Everett's MWI share numerous points in common (e.g. rejection of wave-function collapse), in contrast to assumptions made by the Copenhagen Interpretation. The one downside was that Maudlin and Carroll never quite identified exactly where BM and MWI diverge. Based on Maudlin's account of BM, I'd venture to describe the difference in this way: MWI claims the quantum wave-function comprises a complete description of all events that occur in our reality. The wave-function's evolution over time is dictated deterministically by the Schrodinger equation. Since that evolution produces innumerable states of quantum superposition, each solution of each superposition is manifest within its own separate universe. Thus, the quantum wave-function produces multiple universes whose innumerable superpostions diverge over time without limit. BM claims the quantum wave-function comprises an incomplete description of all events that occur in our reality. The missing factor is the trajectories of the space-time particles that are guided by the Pilot Waves manifested by the evolution of the quantum wave-function. The wave-function's evolution over time is dictated deterministically by the Schrodinger equation. That evolution produces innumerable states of quantum superposition, of which only one solution corresponds to the trajectory of each particle found in space-time. Since there are no particles associated with non-manifest superposition states, those solutions have no effect on physical space-time. Thus, the quantum wave-function produces a single universe in which the trajectories of physical particles are guided by singular solutions to the innumerable superpositions generated by the evolution of that wave-function.

[@schmetterling4477]

BM and MWI only diverge in the way their proponents fail to understand physics. Both are trivially wrong attempts to solve a non-problem.

[@amihartz]

Both are wrong, honestly. BM doesn't even make correct predictions. Maudlin keeps saying he'll fix this but he never shows how. MWI doesn't even make sense, because nobody has ever seen a wave function, only particles, but apparently the whole universe is composed solely of waves? So the whole universe is composed of something fundamentally unobservable? Then how does it explain what we observe? Maudlin is smart for understanding the importance of grounding a theory of specifically what we observe, but he falls short because he is too unwilling to let go of metaphysical prejudices. He wants to believe that everything in the universe is nicely divisible into isolatable things-in-themselves truly in a Kantian sense. There's no reason to believe such surface-level intuition is how the material world actually functions.

[@TheOriginalRaster]

Great Podcast! Thank you so much!

[@davegrundgeiger9063]

It's deeply satisfying to listen to great intellects intellecting!

[@matthijsgeerlings]

What a great episode. Would be great to see a follow up

[@abdouabdel-rehim8537]

one thing I like about T M is that he explains things more clearly. A lot of time, I hear talks like this and I get more confused.

[@Wouldntyouliketoknow2]

@1:08 Sean asserts that virtual particles aren't popping in and out of existence? This goes contrary to everything I have been told.. is this just something that goes away with the many worlds interpretation which Sean holds true, or are there other reasons for this assertion?

[@bobaldo2339]

Some say virtual particles are real, some say they are just "mathematical artifacts". I think it depends on which view fits best with their other pet theories.

[@matthijsgeerlings]

Does anybody know (how to write) the name of the researcher he mentions around 51:30 regarding the faster than light signalling?

[@matthijsgeerlings]

It is siddhant Das, in case anybody wants to know

[@DrDress]

Tim Maudlin! I thought this was an old episode in my feed. He is sooo Mindscapy

[@reyrene]

That was so interesting, especially the part about arrival of time experiments in Bohmian mechanics. For bosons, my vote is for a wave ontology. Bohm and Hiley mention in their book that the particle view of photons doesn't work. Feynman diagrams are the ultimate "shut up and calculate" tool! About quantization, I wonder what Tim thinks about Maurice de Gosson's work (also with Basil Hiley) on Born-Jordan, and symplectic geometry and metaplectic group (i.e., Bohm in phase space). Hiley also claims that the guiding equation cannot derived in "Bohmian" mechanics, but that it is derivable from Schrodinger's equation just as the quantum potential, which is so hated by the "Bohmians". I have to say the quantum potential as an active information field sounds really promising. Hiley and Maudlin need to talk it out publicly. Also, what about all of his work on Clifford algebras and shadow spaces to include the Heisenberg picture too? Looks really promising.

[@nathanmadonna9472]

This is a dope podcast. I love Sean Carroll even if he believes in free will. 😃

[@lucianmihail584]

This is in a top ten mindscape 👏👏👏

[@jl8217]

Two of my favourite speakers, what is not to like.

[@schmetterling4477]

What is not to like is that they aren't telling you the truth. ;-)

[@TheCorneliuscheck]

if space is quantized, what shape (or rather arrangement, if shape makes no sense below that size limit) do the 'sections' have ?

[@schmetterling4477]

Space doesn't have angular momentum. How would it be quantized? ;-)

[@stevemonkey6666]

What a great guest!! 👍

[@BobbbyJoeKlop]

1:22:08-If space is indeed in a constant state of expansion, it does have a fundamental directionality to it. And cannot be reversed. And the asymmetries of the fundamental behavior of space manifest via gravitational attraction.

[@JeraldMYates]

FractalField.

[@spaceinyourface]

Always liked Tim,,,seen him beaten down on other shows by physicists in the past,,not badly,,but hes a clever chap & worth following. Great interview Sean 👍

[@Albeit_Jordan]

51:26 I could swear I happened across an informal Maudlin KZbin lecture further expounding on this point which I thought i even saved to my 'watch later' playlist but can't seem to find anymore. Was it taken down for being too radical or am I just crazy and it never existed?

[@NessieJapan]

Sean Carrol, king of the beef. Lol.

[@vonneumann6161]

Great content! Now my head hurts from thinking too much

[@BradleyMyrick]

What a fantastic podcast, great job.

[@sabre9970]

Wow! Long awaited indeed

[@edwardlarson6110]

I'm very interested in the issue of Copenhagen-think sociology. Before listening to this, I would have said that it's not that 21st century physicists personally believe that quantum foundations is an unimportant or frivolous concern, but that they recognize that it's an intractably hard thorny problem, and that the probability of spinning one's wheels and getting nowhere are high. That can readily explain why physicists eschew QF in their own research programs and professional lives, but it doesn't explain why they would actively discourage students (per examples that Tim described) from asking questions. It's almost as if asking questions is regarded as a deeply taboo form of anti-virtue signaling.

[@gerardopc1]

¡Excelente invitado!

[@polkad3v]

If the arrow of time was in the opposite direction at the quantum level, would that get rid of QM breaking bell's inequality?

[@Al-ji4gd]

I think Tim's historical account may be - well, not may be, definitely is - biased. The same goes for Adam Becker's book, which a lot of philosophers of Tim's ilk (wavefunction realists, hidden variables people, Everettians, etc) seem to be fond of. See someone like Hans Halvorson (and others in philosophy of physics) for a much more measured and technical account of the developments of the past century in quantum mechanics in his 2018 paper ''To Be a Realist about Quantum Theory''. In fact, I would go so far as to say that so much of what goes on in what Tim calls foundations of physics is determined by prejudice (either metaphysical or physics-based). One of the biggest problems with the field, in my eyes, is that they focus too much on non-relativistic quantum mechanics and then basically try to build a picture from there, and that's just not the way to go, in my opinion.

[@schmetterling4477]

You are correct. The nonrelativistic theory is not self-consistent. The relativistic theory is and it does not present any of the problems the quantum mystics are fond of.

[@Al-ji4gd]

@@schmetterling4477 It does present problems, otherwise no one would be arguing about it. It's that we need to account for the relativistic stuff if we want a satisfactory answer.

[@schmetterling4477]

@@Al-ji4gd Nobody of importance is arguing about these things. There is a tiny fringe of theorists who are unhappy that they didn't invent this stuff who are trying desperately to find something in the theory that could make them a name. There isn't. The main issues with the theory were basically solved in 1927/1929.

[@Al-ji4gd]

@@schmetterling4477 I don't think you understand these issues well enough.

[@schmetterling4477]

@@Al-ji4gd Awh, look how cute you are when you are feeling sorry for yourself. ;-) Why don't you ask me. Let's see who knows more. Hint: I do. :-)

[@tofu-munchingCoalition.ofChaos]

11:25 What does it even mean precisely to "care about more than predictions" (slightly paraphrased)? So let's say we have two models that are as good as each other in predicting (and have essentially the same predictive power estimates), what does distinguish them? Is it the consistency and precision of the model (Copenhagen interpretation has a gap that is not closed - when you apply Schrödinger equation and when the collapse - the gap is just not relevant for experiments right now). Then I would agree. But more than that? And I would even agree with physicists that don't agree with thinking that's important. It's outside of the testable range (or at least was) and therefore we can't decide. Or is there something more they mean? I don't get it.

[@tofu-munchingCoalition.ofChaos]

@@lc2000 I hope I understood, what you wanted to express. I absolutely would say that "less equations are better". At least in a vague sense this is correct and that can be made precise. Precisely formulated that is just a *mathematical* theorem in statistical learning theory. I mentioned that briefly in referencing predictive power estimates. So we essentially agree that we need a minimality. But what kind of minimality are you referring to? I say the one that gives the best predictive power estimates and that is up to a constant the Kolmogorov-Rademacher complexity (so the Kolmogorov complexity of a model description and the model is evaluated using Rademacher complexity which is defined up to a constant). That strategy picks essentially one model given experimental data. For all that is presented to me that's many worlds at the moment. I don't agree that we should argue why we want to stop there. If you find a rational reason (for minimality in the right sense it's predictive power estimates) to care about more, then give that reason. If you have no rational reason, then you just have none. I don't see a rational reason to default in what others want to be important. That would not be rational.

[@tofu-munchingCoalition.ofChaos]

@@lc2000 Statistical learning theory developed for understanding machine learning. But it's more like a mathematical model of epistemology that can be applied to machine learning. Essentially it asks the question what strategy (strategy being a function from data to model) in a class of models will give a model that is most likely best at predicting. If you restrict the model class to deep neuronal networks or something like that you get machine learning. If you restrict to mathematically consistent models (perhaps restricted by some computability aspects), then you get exactly what physics asks (and I have never seen an argument to ask for more). What do you think is difficult to unpack here about QM (let's say a generic Schrödinger equation or a concrete non-relativistic Schröder equation)? QM is extremely simple to formalise. Special or general relativity is much more difficult. The standard model is a bit more difficult. That's a different topic and pilot wave is not there either. We don't know if it fits a Schrödinger equation. We don't know what it even is mathematically. Not only the simplest parts are in the rigours of mathematics understood.

[@origins7298]

I have two ideas. One is that it's just an approximation that doesn't have any foundations. Meaning it's just a mathematical approximation of reality, it is not actually reality, and therefore we can't say what the mathematical approximation means... it's a pointless endeavor it's just a mathematical formalism... And the second is that it's simply beyond the ability of our language and meaning system to put into words what the mathematics of quantum physics is saying. In other words it doesn't translate into a cohesive linguistic description...

[@tofu-munchingCoalition.ofChaos]

@@origins7298 I don't think they mean the first. It's pretty common knowledge that you can say for example that "the average is likely close to the expected value" in a statistical sense even if you don't know the expected value. For example by using the *weak law of large numbers* (or more concretely *Chebyshev's inequality* or *Hoeffding's inequality* for bounded quantities) you can derive such a statement. And very similarly this can be done for the "true laws of reality" and models of reality without knowing the "true laws of reality". I'm not sure what you mean by the second. Mathematics is a language. So in a sense it's already "put into words". Do you mean a more intuitive description? But an intuitive description is just subjective. Not sure what you mean with your second idea of what they mean.

[@origins7298]

@@tofu-munchingCoalition.ofChaos Well they're talking about the foundations of quantum mechanics right? In other words they're saying what do the equations of quantum mechanics mean for our understanding of ultimate reality, right?... My point is that maybe you can't put it into a descriptive story like many worlds or Copenhagen or hidden variables. I mean... we know the math of quantum mechanics is very accurate.... But we don't know if it's just an approximation, right? I guess what I'm saying is we don't know if reality at the smallest level is really a wave function or if a wave function is just a good way to approximate what reality is, right? In other words, reality is reality! The universe is the universe! What we are trying to do is give a scientific model that approximates it, right? So I'm saying maybe quantum mechanics is just an approximation, the same way Newtonian physics is... but only more accurate! Anyway... maybe the attempt to say what the mathematics of quantum mechanics means, is ultimately futile! Maybe trying to put it into a linguistic description, like many worlds, isn't science it's just science fiction! maybe those words don't actually mean anything in a scientific sense? As of right now many worlds, Copenhagen, hidden variables, none of those stories mean anything in the sense of giving different predictions or giving us a better more accurate understanding of reality! They are just a bunch of words that cannot be proven right or wrong! Anyway it's like asking what is matter? Well matter is just matter? It's not something that is better describe by other words... Or it's like in Newtonian mechanics the way everything is defined according to other stuff... So in Newtonian mechanics if you want to know what is force? I mean what is it fundamentally?? That question doesn't have an answer! Force equals mass times acceleration. To say what is force in a more fundamental sense is not a meaningful avenue of Discovery! I think it's the same thing here... the reason physicists by and large don't want to go down this road is because it's completely superfluous game of words. It doesn't matter if we call it many worlds or Copenhagen or hidden variables none of those things add anything scientifically... They are just a game of aesthetic musings of philosophical musings it doesn't matter for the science... Anyway Sean always wants to say like it's a meaningful pursuit of knowledge but he has yet to show in any real substantive way that it actually is... and I would argue that if humanity continues for a million or a billion years it won't be illuminated or elucidated any more than our current understanding... That is at least my intuition, I think you ultimately hit a level, a scale, the plank scale in this case, from which you can't get any more fine-tuned explanation of reality it's just the way it is!

[@stefanbernegger9740]

I was quite surprised when reading the various euphoric comments. There were a couple of situations when I was struggling with Tim's statements, and I don't quite understand why Sean did not correct him (well, maybe Sean's laughing at times tells all). One such situation was around minute 34 when Sean and Tim were discussing David Bohm's interpretation of QM. Sean mentioned the objection by many physiscist which is the volation of Newton's "action = reaction' principle" (the pilot wave acts on the particle but the particle does not impact the pilot wave). Tim rejected the objection by referring to Newton's theory of gravity and this objection by Tim "struck me as just silly" (using Tim's words). Tim has written books about relativity and he should know that this shortcoming in Newton's theory of gravity (Newton himself was well aware of the problem) was corrected by Einstein in his theory of general relativits (GR). In GR, the masses are determining the curvatutre of spactime (the equivalent of Newton's gravitational field) and the curvature of spacetime determines the trajectory of masses (the equivalent of Newton's gravitational force), i.e., it is governed by the "action = reaction" principle. It is this thus difficult to understand how an incomplete theory (Newton's gravity) which violates Newton's third principle can be used to justify the violation of this principle by Bohm. This is not the first time that I am struggling with Tim's arguments (another case is Tim's metaphysics of time), and I was only surprised that Sean just let Tim talk no matter the sillyness of Tim's arguments - If being in Sean's position I could not have zipped my mouth but I appreciate how Sean treats his guests.

[@najawin8348]

You're slightly confusing two things here, the _gravitational field_ (or gravitational curvature) and _the law of gravity._ Maudlin and Carroll are explicitly, in this section, denying that the pilot wave is analogous to a Newtonian force field, so it wouldn't have the flaw you're suggesting. (Instead of asking Newton about the Law of Gravity, you'd ask Einstein about the Field Equations. Do the Field Equations change because of the distribution of matter?) (This gets into some of Maudlin's specific views and I haven't read him in a while, but I _do_ think he considers the quantum potential to be a physical law similar to the field equations. Again, been a minute, might be misremembering.) (Edit: Did a reread of some of his comments, this isn't quite right. 'As Shelly Goldstein says, the quantum state has something of a nomological flavor: if you want to analogize it to something familiar, it is more like a law than a classical field. Personally, I try to lay off the analogies. Quantum states are quantum states. They aren’t like anything in classical physics. Or, as David Albert once put it, “we’re here, we’re qu*r, get used to it”.')

[@soppaism]

GR is a classical theory, which in any case is in conflict with QM, does it even matter here? "pilot wave acts on the particle" is this even a good way to put it? If it's is a fundamental theory, isn't it just "pilot wave describes how particles behave"?

[@QuicksilverSG]

Here's the difference in a nutshell: Gravitational and electromagnetic waves propagate relativistically through physical 3D space at the speed of light. Pilot waves, as do all manifestations of the quantum wave-function, propagate instantaneously throughout Configuration Space, the complex-valued domain of unlimited dimensions where the wave-function is defined. The mechanism by which Pilot Waves "guide" their associated particles is known as Born's Rule - a probabilistic projection of the deterministic evolution of the wave-function into relativistic space-time. The reason particles do not affect Pilot Waves is because there is no mechanism by which particle trajectories in space-time can act upon wave-function evolution in Configuration Space. This is not just a tenet of Bohmian Mechanics, it is a principle all interpretations consistent with Quantum Mechanics agree on.

[@primus4cameron]

(35:02) "But what of particles? Don't they affect the law of gravity? ....No. Of course not. The law of gravity doesn't change because of what the particles do" What? The very presence of the particle changes the curvature of spacetime. There IS a "reciprocal or back influence" The gravitational "law" doesn't change but the gravitational field surely does. With no push back from Sean Carroll I suspect I've missed the point.

[@noiseworks]

particles don't change the law itself, but they do influence the conditions under which the law operates, thus shaping the gravitational field ?

[@primus4cameron]

@@noiseworks That's my point. But Maudlin seems to repudiate any such influence, does he not?

[@MNbenMN]

I think the point was that the law of gravity (assuming it is complete and accurate) describes the behavior of particles (on large scales), but the particles do not describe the law since it already accounts for the behaviors of the particles. In other words particles effect each other's behavior according to the laws of physics (including the law of gravity). I think Maudlin was only using that as an example of how there doesn't always need to be a "back effect". I think it would have been clearer if the example was more like dropping a stone into a well. A dry well will result in a different sound than a well with water at the bottom when the stone reaches the bottom (or surface of the water), but whether the well is dry or wet doesn't have any effect on whether the stone was dropped in the first place. But, I may have missed the point, since the law of gravity is a concept, a metaphysical construct abstracted from empirical observations, and the behavior of the particles are ( I presume ) purely physical and directly observable so there might have been something implied around whether metaphysical effects physical and vice versa. Ultimately the law of gravity as we understand it was figured out by looking at behaviors of physical objects, that we accept as being composed of particles, so the particles' behavior did (in a way) effect the law which is based on those behaviors. However, it appears that the law is constant and particles (on large enough scales) conform to the law, not the other way around.

[@primus4cameron]

@@MNbenMN Thank you for your uncontentious yet thought provoking reply. Quite the clarification. Much appreciated

[@najawin8348]

@@primus4cameron Been a while since I've read Maudlin, but iirc MNbenMN is getting his view correct here. The two are distinguishing between the Law of Gravity and the Gravitational Field. I believe Maudlin considers the quantum potential to be a Law. Edit: Did a reread of some of his comments, this is not quite true. 'As Shelly Goldstein says, the quantum state has something of a nomological flavor: if you want to analogize it to something familiar, it is more like a law than a classical field. Personally, I try to lay off the analogies. Quantum states are quantum states. They aren’t like anything in classical physics. Or, as David Albert once put it, “we’re here, we’re qu*r, get used to it”.'

[@cademcmanus2865]

Really good ep

[@paulbirch8576]

Totally on the same page as Tim!

[@davidkemp3154]

Schrodinger evolution requires preference & fine tuning not just wave function. The preference reflects a teacher/pupil dynamic extracted from multiverse best case scenario timeline dynamics but conservation of energy provides the rules for the uncertainty to unwiggle tself into scalable wave function aka Schrodinger's evolution- which includes God (scalable as above so below) as it were.

[@iAnasazi]

Maudlin sounds a little like Lawrence Krauss, while Roger Penrose sounds a lot like Geoffrey Hinton. Agree?

[@kylosun]

Sean, as a visual learner, I've long wished we could see some faces on your podcast!

[@techteampxla2950]

I have been studying universe , physics, and all of you for years now. Thank you for all the great work you guys do. Today driving home from work I realized the universe has a up and down. Maybe a north or South Pole I don’t know , but the formation of stars should show the mathematics of this and we will have it soon im sure. Also black hole symmetry will add more evidence along with star formation and destruction, formation of black holes, also this might support many universe, because if we have a up and down , I feel like it rains , flows , creates universe, then goes south poles holes into the next, into a never ending process , I don’t know , I imagine a lot , don’t listen to me. More realization was I studied our star ⭐️ the sun , and of our star can have the fusion power to do the amazing things it does , imagine “fusion” in the black hole an “near infinite cooking pot” then when it explodes and begins to materialize it gains energy in massive amounts…stars really try to poke the hole to the next “fabric” it’s afterlife for them and crucial for the never ending process…

[@techteampxla2950]

@@GeezerBoy65 I have some shrooms if you want some , it might help in more positive construct of criticism in some cases.

[@DrewTrox]

Are there any theories where the expansion of space and time are a phase transition of some fundamental field?

[@DrewTrox]

I imagine a block universe. Like super cooled water. There's a nucleation site and it freezes. The Block Universe collapses on a timeline. Like the charged air in a thunderstorm. You have a sea of infinite probability. Then once in awhile there's a bolt of lightning.

[@csours]

'No two philosophers will ever agree with each other on everything' - does any philosopher ever agree with THEMSELVES on everything? I know I don't and I'm not even a philosopher.

[@johnphil2006]

Theory is primarily a form of insight, that is a way of looking at the world, and not a form of knowledge of how the world is. - David Bohm.

[@PedroDiMaggio-dk4lb]

John, could you please recommend any books on this man, his life or his thought?

[@Mesohornet11]

yes!

[@origins7298]

Similarly, any linguistic story we can tell is different than math, so it might be that all of these stories or foundational interpretations are just never going to be accurate due to the limitations of language and meaning... And therefore it is science fiction in the most literal sense of those words.

[@essecj59]

Possible FTL communication makes me excited about the reality of UFOs.

[@origins7298]

Isn't it possible that the best we can do is approximate reality, and therefore quantum physics is just another albeit better approximation.

[@marcgenest]

I've always visualized zero point as fulcrum and big implosion/big bang as the teeter tottering if you will. 1st oscillation at Plank length. Explosion(bang) & Implosion being mutually inherent. Explosion(bang) +1 & Implosion being -1 The zero point is fulcrum between 2 exclusively different , ie. action chaos and reaction chaos, oe alpha omega emerged asymmetrically (+hi \Zero/ -low ) and both have an asymptotic direction(in/out), they are not symmetrical, they are 2 separate time domains of information and function. Mutually inherent. Am I, iAM yes, but the initial bang was at Planck level size. So we and everything stems from it. Alpha Z Omega started at nothing or Zero time. All emerged from the mini Planck poop or pop. ...lol 😂 Lorenz attraction is alpha omega Z is a black hole that decides which domain intel / reasoning wins. The black hole 🕳 can be any form , sphere with extension (or proboscis) extending its trinity /black hole described as (𝞪↑ℹ↓Ω) iAM (𝞪↑ℹ↓Ω) iam (mini Black hole) body ...entangled. Asymptote infinity out alpha Asymptote infinity in omega The Z is the zero plane , where the 2 infinity's ride the flat universal plane.. Upper +alpha universe mind domain, right spin neutrino Lower -omega universe body left hand neutrino. ALL LIFE IS LEFT HANDED NEUTRINO Z is neutron , contains alpha Z omega. Yin ⚍☯⚎ yang

[@schmetterling4477]

Are you getting help with that? ;-)

[@robmorgan1214]

It's so frustrating watching these guys talk about something that's been answered and available in the literature for more than a decade it's not "as hoc" 26:21 . Wojciech Zurek proved that Born's rule is a direct consequence of the algebraic structure of the theory period. Hilbert space + Unitarity + instantaneous reproducibility of repeated measurements strictly imply Born's rule as a DIRECT result of theorthogonality of non interacting states via Graham-Schmidt... the proof is pretty elegant and simple.

[@schmetterling4477]

The Born rule wasn't "ad hoc" back in the days, either. It acknowledges that the spectrum of the measurement system folds into the result of the measurement. Other than that the quantum mystics are laboring so hard to prove only one thing: that they are ignorant that their approximation of nature is not how nature actually works. ;-)

[@odal6770]

Does the moon only exist when we look at it? It is certainly logically possible. But since we cannot exclude the possibility that, at any time, somebody is looking at the moon, somewhere on earth or the universe, we may safely assume that the moon exists continuously. It becomes quite something else if there is only one consciousness, mine, in the universe, or wherever, and everything is a product of my consciousness. In such a case, I cannot claim with certainty that the moon continues existing when I stop looking at it. It would be the same as saying that a thought of mine continues to exist even after I have stopped thinking it.

[@odal6770]

Replacing the moon with any physical object or phenomenon, and "looking" by any kind of measurement, we arrive at the inevitable conclusion that the Copenhagen Interpretation cannot be considered as a scientific theory This interpretation only makes sense in a universe with a single consciousness while science assumes the existence of others who can replicate any experiment.

[@schmetterling4477]

@@odal6770 Why are you telling us that you don't understand Copenhagen? We don't care. ;-)

[@odal6770]

@@schmetterling4477 You remind me of someone who, in another forum, had a very unhealthy fixation on me. You should get a life.

[@schmetterling4477]

@@odal6770 I like finding trolls. I have found another one. ;-)

[@odal6770]

@@schmetterling4477 well, as long as you have fun.

[@Ballosopheraptor]

Love Bohm and Tim! The fact anyone would prefer many worlds over hidden variables is wild to me, especially since hidden variables only relies on entanglement which WE ALREADY KNOW HAPPENS AND IS REAL, whereas many worlds requires faith in this process we can never observe or prove.

[@sszone-yt6vb]

Well you have to attend to ALL the possible experiments when thinking along happily about your favourite theory of anything. Bohmian mechanics is very hard (as far as I know hasn't been done yet at all) to generalize to relativistic quantum field theories. So it cannot predict anything there correctly. If it could, I think it would be something many many-worlder would consider seriously.

[@najawin8348]

@@sszone-yt6vb There are some toy models that show proof of concept. Nothing a small army of grad students couldn't solve. There's just no funding to actually do a BM model of QFT.

[@sszone-yt6vb]

@@najawin8348 Yeah, I agree with that. Basically what I am saying is, IF it does get solved; produces same predictions for all known phenomena (QFT...) as the many worlds(if the predictions are different, that would be many million fold more interesting) then many worlders would indeed have a proper theory to look into. It would then become equally compelling as many worlds for Everettians. I speculate that the main point of elegance would come down superluminal information transfer(between the unobserveable variables )/locality. I am actually curious about those toy models. Could you point me those somehow?

[@najawin8348]

@@sszone-yt6vb Discussed in the interview, no? Bell's paper "Beables for quantum field theory" is sorta the first. It's _very_ much a toy model. But some work has been done on other models.

[@jonathanhenderson9422]

I don't know what you mean by "only relies on entanglement;" many worlds makes sense of entanglement as well and does it without violating locality. I also don't know what you mean by "requires faith in this process we can never observe or prove;" we observe superpositioning in double-slit experiments all the time. The problem isn't observing them, the problem is answering the question what happens when we measure them, why the other states seem to disappear. Many worlds says they still exist, but we can't interact with them because we (and the environment) are too entangled with each other; Bohm says some hidden variables select which outcomes happen; Copenhagen say all those possibilities collapse to one. All of these interpretations are experimentally indistinguishable, making the issue philosophical. For those who place value in Occam's Razor as an epistemic principle, as Sean Carroll and I do, Many Worlds is attractive as it's the only interpretation that isn't adding anything to the fundamental formulas requires to make QM work. What requires "faith in (processes) we can never observe or prove" is the faith that there are hidden variables or some ill-defined collapse mechanism, all of which create problems of their own, especially in their conflicts with general relativity.

[@devalapar7878]

I mean there is nothing wrong with the approach going from the simple to the more complex. That's how we usually solve and understand problems.

[@techteampxla2950]

ProfTimMaud and DrCar , after watching hours of physics videos I ran into one studying the geometry of the universe. I realized from a joke some one made we can possibly prove time exists, im not sure . He said the universe starts at a 0.0.0 coordinate , this means if we map the universe and learn to map gravity and dark matter motion , that would equate to time. Imagine like ProfFey said , use nature as our guide maybe dark matter is like magnetic like energy and everything here is positive energy , they are pushing and pulling on each-other in a way I am sure we can understand . That expansion is “non exclusively” time in the real ??? This is when we can use the universe as a clock instead of the sun ☀️. I think the Mayans and those before them tried this with amazing success for the technology they had at their time.

[@wizardatmath]

I caught the diplomatic dismissal of the "sociology" of Physics departments. And thus, you miss the entire point that Tim is making, and your crisis in Physics is right there, in front of nose.

[@schmetterling4477]

The only crisis here is that folks like you aren't paying attention in high school when we are explaining quantum mechanics. ;-)

[@dondovahkiin7899]

Bohr was so Nice nobody dared to disagree with him to his face and so his interpretation stuck.

[@CurtOntheRadio]

10k views, 350 thumbs up. Press the button, people?

[@bryandraughn9830]

Check out the people in the comments who are listening to a conversation that they don't want to listen to. Or the ones who have solved physics. It's hilarious!

[@kathyorourke9273]

It’s clear that we just don’t understand everything yet. It’s hard to tell a story that’s missing chapters.

[@psmoyer63]

Philosophy asks questions and science answers -- Question: What is the universe doing? Answer: Making lots of Empty Space (aka the quantum vacuum, dark energy, etc.) Question: How long has the universe been making this empty space? Answer: 13.8 Billion Years. Question: When were all the particles created? Answer: 13.8 Billion Years Ago. Question: What are all the particles structured to do? Answer: Make Empty Space. Question: What created the particles? Answer: Exponentially inflating Empty Space. Question: Where do the laws of physics reside? Answer: The Quantum Vacuum of Empty Space

[@psmoyer63]

All the mysteriousness in cosmology is purely anthropic.

[@origins7298]

And that is the reason why we can not settle its foundations... because it's just an approximation that doesn't have any foundations?

[@HarryNicNicholas]

can you just get back to me when physics is finished. or, how will this get me into space with the faster than light drive?

[@garageliftrunner]

Here's a fun one. Imagine you go spelunking in an 3D orthogonal space. Minkowski. Nothing is weird. You find dimensions move with the same observer. It doesn't appear relative. And if you do this in a complex geometrical space, you get weird, informational results. For example, an edge or vertices may be relative to the entire structure, perhaps a 3D structure which is nested in a 4D or 5D structure. And depending on the vertices or points youre observing, it might appear as if the sub structure looks relative. And this is because if we put the 5D structure in Hilbert Space, which we can do in multiple ways, something something. And this is more clear, if we add time. Because if we convert the 4D shape to a wave, moving through time, the geometry appears to have an amplitude. So relative to a 3D structure, it might appear that the QG is different, depending on something something. The points observing.

[@Heater-v1.0.0]

Wait a minute, Newton came up with some neat equations to describe motions of masses and gravity. He famously said that he had no idea how or why that mathematics works. Sorry I cannot remember the quote. Nobody worried about that for 300 years or so. They just "shut up and calculated". So my question is why did the founders of quantum mechanics have any embarrassment about having no idea why or how their equations work and feel the need to create some mumbo jumbo about it?

[@ryanparmater4899]

newton literally invented calculus to explain his mechanics, so that first statement is not true. nobody just shut up and calculated newtonian mechanics; its physical implications were quite clear from the outset. the second statement re: the founders of QM feeling any embarrassment about how or why their equations work... i mean... did you listen to this discussion? their embarrassment about having to come up with the shut up and calculate approach was precisely due to how clear both einsteins and newtons and maxwells theories were about what was actually physically happening, whereas the Copenhagen crew was just doing math without having a clue about what it was telling them was happening in the world.

[@schmetterling4477]

Where the 1/r formula comes from was already known to Gauss, approx. 100 years after Newton.

[@schmetterling4477]

@@ryanparmater4899 Dude, the confusion in quantum mechanics goes back to Einstein. He caused it and he never cleared it up. You were clearly never reading his photoelectric paper with both eyes open. The Copenhagen interpretation tells you exactly what happens in quantum mechanics, you are just not listening. And if you want the proper mathematical analysis of "where all of this comes from", it's in von Neumann's book from 1932. That's one year before Kolmogorov published his probability theory axioms in 1933, but von Neumann already knew before him that his axioms have a second, non-commutative solution. That solution is quantum mechanics. You need to stop pretending that you are either smart or well read because you are neither. ;-)

[@luchochemmesvilches6163]

Particles and wavefunctions are just abstractions that work on paper, I would claim only space exists and it curves in higher dimensions, maybe fractal dimensions, and the result of its arquitecture defines the relations we call constants. Also these "dimensions" are only spatial and time being the forth is lame, time only arises from changes in structure, if theres no space there is no matter nor time.

[@OBGynKenobi]

Quantum Theory: Imagine a spinning particle, except, it's a pepperoni pizza that just fluctuated.

[@yacc1706]

9:16 Bohr philosophy

[@Bryan_S_Monroe]

I might be or have been a horrible person in the past I just want to help my family and veterans doing something productive moving forward

[@bencze53]

6:06

[@yacc1706]

8:37 another crew, Sean laughs

[@yacc1706]

12:48 neither professors nor textbooks have the answers

[@schmetterling4477]

von Neumann had the answer in 1932. It is correct that we aren't teaching the topic correctly in QM 101 classes but you can easily find it in early books (starting with Heisenberg's matrix mechanics paper) and some later foundational papers that derive quantum mechanics cleanly from Kolmogorov's axioms (more cleanly than von Neumann who is a bit hard to read from a modern perspective, but it's all in there), IF you are willing to read them. That is hard work, of course.

[@JohnEButton]

You ask Tim about what he thinks and he has a tendency to somehow talk about why he doesn't have to believe contrary positions

[@jasonsmith373]

Excellent interview - Sean is really good at this side gig. As for Tim, he's so damn dreamy that I could just sit and listen to him talk for hours and hours.🫠

[@robmorgan1214]

It's so frustrating watching these guys talk about something that's been answered and available in the literature for more than a decade. Wojciech Zurek proved that borns rule is a consequence of the algebraic structure of the theory period.

[@aforementioned7177]

I thought the Nobel Prize in Physics in 2022 was given because they proved hidden variables incorrect?

[@gilbertanderson3456]

No, the Nobel committee did state that, but the prize was awarded for experimentally confirming that nature violates the Bell Inequality. The people writing up the description didn't understand what violation of the Bell Inequality meant. The violation proves that a LOCAL hidden variable theory cannot explain what we observe in nature and that we must accept that Nonlocality is a fundamental component of reality. A nonlocal hidden variable theory is the best hope for a deeper understanding of nature. Everetian QM is a form of "shut up and calculate" that assumes the Schrodinger equation captures all of reality and accepts that the "many worlds" implied by the absence of a collapse mechanism is an unprovable fact of reality. Unbelievably sloppy thinking.

[@petertaylor4954]

Physicists beefing on youtube? Let's gooooooo 😂

[@yacc1706]

12:23 young students want understand

[@playpaltalk]

Thinking of bits a qubits 🤔

[@MichaelScarborough423]

I swear, Sean's voice sounds just like Howard Stern, lol.

[@ricomajestic]

Not even close

[@MichaelScarborough423]

Sounds precisely like Howard Stern. I mean exactly.

[@ricomajestic]

@@MichaelScarborough423 Get your ears checked. Howard has a much deeper radio voice!

[@willnzsurf]

🌴😎💯

[@willnzsurf]

kzbin.info/www/bejne/opnUd3yElsatl6c

[@logictophysicscom]

I suppose if you want a complete theory of physics beyond question, then you'll have to be able to derive physics from logic alone.

[@CorwynGC]

How would that be Physics? It would be Logic. To be Physics it must be derived from Reality.

[@logictophysicscom]

@@CorwynGC Are you saying reality is not logical? Or are you saying that physics cannot be based on logic? I would think that neither of these two ideas can actually be proven.

[@CorwynGC]

@@logictophysicscom You seem to be confusing "logic" with "logical". "Logic" is a class of math which exists without reference to reality. "Logical" is a colloquial term to describe arguments not inconsistent with the rules of logic. Physics can NOT be based on logic, it should be derived logically, but it must also model reality, and be subject to experimental verification. Reality is under no obligation to be logical.

[@logictophysicscom]

@@CorwynGC You are making an inherently unprovable assumption, that somewhere in reality, facts may be somehow inconsistent. If all facts are consistent with each other, even at the smallest level, then that means reality is based on logic. You are probably thinking that somewhere in the physical realm there are facts that are brute facts, that do not and cannot be derived by any more fundamental thing or principle. Perhaps you think the initial conditions are arbitrary (not derivable by logic). Or perhaps you think that how the symmetries of physics may have broken is arbitrary (no reason for it). But that's an unfalsifiable theory. It is just an assumption that negates any reason for why things turned out that way. I think that if everything is logically consistent at all levels of reality, then that is equivalent to being derived from logic. What do you need to see, the laws of physics actually being derived from logic?

[@CorwynGC]

@@logictophysicscom you have no understanding of what logic is. I am sorry about that ,but I can reconnect a math course in it as it is a fascinating subject.

[@origins7298]

because as of now it is meaningless to actual physics... Yes it's interesting, but the pushback from physicists is because it doesn't go anywhere... It has never been shown to matter to the actual mathematical theories.

[@igor.t8086]

Isn’t the world such a funny place? (Or, multi-level funny place, indeed…) But, then again - it’s all wavefunctions, right? Some wavefunctions are funny, same wavefunctions are physicists, others are philosophers etc. It’s just the way they evolve - and they do evolve according to the Schrödinger equation. Wait; I made the error again: wavefunctions ARE philosophers and physicists and artists and physicians (and many other probable things) all at the same time, just in different worlds of Many-Worlds Quantum Multiverse… But, Sean: How do you assign accumulated knowledge and personal (autobiographical) memory to such a wavefunction in any of the worlds? Are the memories and feelings and personally gathered & systematized knowledge part of one and the same wavefunction (option that I cannot fathom) or are those represented by independent (more or less hidden) variables? How does one separate the terms in wavefunction that describe, say, personality from those that are related to accumulated knowledge (of said wavefunction)? I’m really curious to know… (Actually, “personality wavefunction terms” may turn out to be compatible with Zodiac and the natal charts - which I regard as pseudo-random character generator, albeit of one universe…) However, I am not here to start a quarrel; I want to be remissive now that Sean invited likeminded fellow to the show… (Sometimes I have funny ways of verbally expressing myself.) And, funny thing, again: Apparently, Maudlin and I work on similar ideas… Go figure! Wait a minute! That means Maudlin and I are “conceptual competitors” - or “competing wavefunctions” - or whatever… In that case, maybe I would rather want Sean to be on my side? (I’m thinking out loud… I’m pondering my options…) Ideal solution: Tim and I join forces of persuasion and “convert” Everettian Sean wavefunction to passionate adherent of De Broglie-Bohm pilot-wave theory… [“Yeah? Not gonna happen…”] Surely Sean would’ve been the most effective ambassador of free will (of Bohmian mechanics) - of that I’m positive… (He speaks nicely, dresses nicely, and commands a good knowledge of both quantum physics and classical philosophy…) OK, enough of small talk and exchanging pleasantries. Sean, what did you mean by “initial conditions (may) set the arrow of time”? Like, whatever non-equilibrium state at the beginning eventually settles to equilibrium - and voila, the arrow of time is defined? Which candidate quantum field did you have in mind to be the major field to be observed in this manner, for this purpose? I can picture that particular field as a vast ocean, with many, many different currents (a.k.a. “time flows”) running in many different directions, at many various speeds… (But, the time doesn’t flow…) However, I am so conservative in this regard. (So: not gonna happen… Also, I have some other ideas, but I’m not telling you about them here - because you-know-who… (Maudlin.) ;) But, there was one other thing I wanted to ask you… (I either wanted to but eventually didn’t ask Matt O’Dowd - or he didn’t answer me… Maybe I should talk to ChatGPT instead? Just thinking out loud again…) Two-part question… We have 2 sets of 8 entangled particles (like the 8 bits of good-old ASCII code, sets entangled 1-to-1) in 2 different physical locations… Actually, make it 4 sets of 8 - because we’ll use simplex communication (“here” & “there”, times, “input” & “output”, crossover connection). Up front, we agree on how we’ll measure the spins and, most importantly, we synchronize the clocks… Now, I know we could flip a spin without affecting the entanglement (but I forgot how exactly that is done)… Part #1: Can we perform weak measurement of the spin without causing decoherence? Part #2: Is the spin measurement an idempotent operation? If both answers are YES: voila; mission accomplished! Although the preparation will always be sub-FTL, the transmission of this classical information is “instantaneous”! Am I right? 😉

[@bryandraughn9830]

Or.... Jiffy peanut butter on white bread. Checkmate!

[@chrisstanford3652]

🤗

[@origins7298]

there is no difference between many worlds and Copenhagen! They're just different linguistic contrivances! I mean if we want to say the universe branches or that the wave function collapses, there is zero difference between these two sets of words from a practical standpoint! That's what I mean when I'm saying it's all just a game of words... at the end of the day the math is still the same... The results of this experiments are still the same... It's just a different and superfluous, linguistic story, to describe it... It's like if you draw a cube that can be seen from two vantage points on a blank piece of paper. It's not like one of the cubes is more real than the other way of seeing the cube,... The reality is that you have ink on a piece of paper that can be seen from 2 different perspectives... That is what is going on here... they're just arguing over which cube is the right cube... when they are both just abstract ways of talking about ink on a piece of paper... or in this case a mathematical approximation of reality! This is the truth... and this is what would end all these discussions.. but people love to titillate their senses so...

[@bryandraughn9830]

Maybe they feel like talking about the things that they like to talk about. You should really get in touch with them and explain your concerns. I bet they're not listening to someone else having conversations that they aren't interested in. That would be pointless.

[@origins7298]

@@bryandraughn9830 dude, obviously they can talk about whatever they want to, I'm not saying it's not even interesting... I'm just explaining why most physicists and physicist departments aren't interested. Because it doesn't change anything about the math. It's just a bunch of words attached to try to give people some sort of conceptual understanding of really non-intuitive math and phenomena. There's nothing wrong with talking about it, I even find it interesting myself, I'm just explaining that at least with all the evidence we have it doesn't matter if you believe in Copenhagen or many worlds. The math is exactly the same. It's really just a bunch of words added after the fact to try to explain something that is very non-intuitive and probably something that can really not accurately be put into words Again it's cool to talk about but I'm just raising the serious concern that maybe we can't accurately describe it with words and language It's just something that is mathematically true that can't be put into words... I don't know why everyone is throwing a hissy fit and acting all offended that I'm raising this point. You guys are acting like religious dudes who are all offended that someone's pointing out your religion doesn't make sense.

[@rigunpipina9228]

I think tim don't have the full expertize in quamtum mechanics, general relativity and statisticall machanics to talk about the underlaying Nature of reality, or at least it seem so...

[@palfers1]

Just excellent.

[@origins7298]

Unless you can show that it matters to physics a speculation about quantum foundations belongs in philosophy

[@najawin8348]

"Unless you can show that it matters to physics a speculation about quantum foundations belongs in philosophy" Einstein was directly inspired by the work of Mach in what we would consider early foundations of physics. Bell was directly inspired by the work of Bohm for his theorem. The Bell Inequalities have clear applications. Recently work has been done by Bohmians to find Time of Flight calculations and begin testing them. If successful this would clearly have applications. But none of this matters. If all you want is applications go to an engineering department. In physics we care about what reality _is._ And foundations of physics is fundamental for that project.

[@origins7298]

@@najawin8348 but the math is the math! That's my basic point... It doesn't matter what words you attach to it everyone agrees on the equations... Whether you explain it by a wave function collapsing into a particle, or many worlds branching, doesn't matter those are just semantical jargon, or story told after the fact... Unless you can show that the math changes and somehow you get better results than none of that after the fact storytelling matters... Again my basic point is that these are all attempts to put what is a mathematical formulation and make that fit into our language and syntax and grammar and ability to conceive of the world through our intuition... These are all just stories told to try to give people a grasp of what's going on but they aren't reality they aren't the actual models they are just stories told after the fact to try to make it accessible to people

[@origins7298]

@@najawin8348 further being inspired is different than those foundational arguments actually meaning anything. My point is that the Copenhagen interpretation verse many worlds is just trying to make it accessible to our linguistic minds, neither of those changes the mathematics

[@najawin8348]

@@origins7298 First of all, you're just wrong - the equations of Bohmian Mechanics imply specific things about trajectories and time of flight calculations that other people deny. Second of all, math is not the end of physics. Read Duhem, _Physical Theory and Experiment._ Physics isn't just mathematical descriptions. If you want this you're in the wrong field. Physics always attempts to explain the phenomena.

[@origins7298]

@@najawin8348 Well it's nice for you just to declare who is right or wrong in an argument. I guess I'm conversing with God. I'm talking about many worlds versus Copenhagen. It's the exact same thing it's just a different spin on what is happening. It makes no difference if you say the wave function collapses or the world's branch. They're just linguistic placeholders for our intuition or our need for a linguistic explanation. Isn't it possible that it's just something that cannot be put into words? Isn't it just possible that at the quantum level at the most fundamental level it's not something that can be put into a linguistic model. It's something that defies words. I mean seriously you don't think that's a really strong possibility... Anyway it makes no difference if you're building a quantum computer if you believe in many worlds or Copenhagen. And that kind of proves that I'm right. Because unless you can show that you can actually do something differently with many worlds that you can not with Copenhagen then you are 100% wrong The proof would be in being able to produce some technology or some experiment that only works with a many worlds interpretation versus Copenhagen If an interpretation has different math then of course that is something that different but that is not the accepted formulation the accepted formulation are the quantum mechanical equations that govern quantum mechanics. Such as the Schrodinger equation Those are the ones that have all the experimental support!!!

[@kencreten7308]

it would be a lot better for the naysayers or the supposed naysayers of shut up and calculate if some actual results could be found for one of the interpretations. Right now all we have is hypothesis. if you're actually doing physics then the foundations don't matter. if they don't matter then calculate. they'll matter when they're shown to be the case but they aren't the case yet. nobody knows how to make them the case apparently. so I'm sorry you guys are not happy about it but show some results.

[@helicalactual]

what would you use as the standard for success in this area?

[@helicalactual]

@@alanjenkins1508 not an answer to my question. Perhaps try again?

[@mrglassscience]

I agree with you, if what you care about is just explaining the results of experiments in terms of equations. Now, that is fundamentally important to building things and making technology and all of that. But maybe some of us commit a lot of our mental energy into learning this stuff because we were excited about how Physics fits into our larger understanding of what reality actually is, and not just because we like working out complicated equations?

[@helicalactual]

@@mrglassscience well put

[@gilbertanderson3456]

@kencreten7308 If the foundations don't matter then GR is a waste of time, use Newtonian theory. Don't try and understand any more than addition and subtraction and be satisfied with being ignorant.