Where we stand-Baez talk at Luminy

[marcus]

where we stand--Baez talk at Luminy

a simple rather beautiful talk

http://math.ucr.edu/home/baez/where_we_stand/


mentioned in yesterday's TWF #227
http://math.ucr.edu/home/baez/week227.html

 

[marcus]

http://math.ucr.edu/home/baez/where_we_stand/
"Fundamental Physics: Where We Stand Today"

"Fundamental" matters seem to be a major focus of attention just now. Probably it is due to some difficulties at the foundation/methodology level---or perhaps the string embarrassment.

Smolin just published "A Crisis in Fundamental Physics" in the New York Academy of Sciences magazine.
http://www.nyas.org/publications/UpdateUnbound.asp?UpdateID=41

Both essays are for general audience, and give historical account of string plight and hep-th doldrums.

Here is how Baez starts off:

"By fundamental physics, I mean the search for a small set of laws which in principle determine everything we can calculate about the universe. The reductionist dream – not always practical, but very seductive.

Where do we stand in the search for these laws? What do we know, and what are the mysteries? Why do many physicists feel stuck?

Let us begin with the story around 1983, ..."

 

[f-h]

Most remarkable about the talk is that it is a stinging critizism of contemporary theoretical physics without actually ever mentioning it.
Rovelli called Baez on that asking wether what he had just presented didn't imply that the theoretical physics of the last 25 years was "junk". To which John baez replied after some hesitation "You said it".

Fabulous talk, if you have the chance to catch John Baez talk about anything at all, go. He's a fantastic speaker.

 

[marcus]

Most remarkable about the talk is that it is a stinging critizism of contemporary theoretical physics without actually ever mentioning it.
Rovelli called Baez on that asking wether what he had just presented didn't imply that the theoretical physics of the last 25 years was "junk". To which John baez replied after some hesitation "You said it".

Fabulous talk, if you have the chance to catch John Baez talk about anything at all, go. He's a fantastic speaker.

an exchange between two people I respect highly
thanks for the report f-h

 

[selfAdjoint]

Baez attributes the, how shall I phrase it? - stiffness of the string physicists to the usual suspect, pride. But looking at the discussions, and especiallt the comments thread at Not Even Wrong over Smolin's new essay, I suspect there is something that goes deeper. Back to the way physics students are trained, at least in US grad schools.

To learn quantum physics you have to make a leap of faith. You can't really learn it "conditionally"; if you try you'll always be fighting yourself and unable to think freely enough in the field to do good work. You have to accept that quantum physics with all its counterintuitive assertions is to replace common sense physics in your mind and "heart".

Now the teachers have to motivate their students to make this leap, and I think they do it by offering them a deal; buy into QM and we will teach you how the world really works. We may not have that final theory yet, but it exists, and yours may be the generation that reaches it! And the students who go on to work in high energy particle physics accept this and are invested in it to a great and deeply emotional degree.

Other physicsts - those who go into condensed matter physics or especially those in relativity research, don't have anywhere near so much investment in quantum weirdness, although some of the GR physicists seem to have caught some of Einstein's triumphalism (If the experiment disagres with my theory, so much the worse for the experiment).

This really makes for a two cultures split in physics and my point is that it's not about stupid academic politics or such though it entails much of that, it's about the DEARLY BELOVED TREASURE OF THEIR HEARTS.

The last time we had so much rancor in a scientific discipline it was the sociobiology wars between the strong evolutionists and the basically Marxist tabula rasists, and then too, it was about deeply felt and irreconcilable investments of the heart.

 

[Chronos]

A bit philosphical compared to the usual SA slant on things, but, I agree. Us old people are slow to reach conclusions, but cling to them with tenacity. We live in a causal universe. Despite the success of quantum physics, I think Einstein was closer to the truth . . . God does not play dice . . . at least not the way we cast them.

 

[f-h]

SA, my immidiate reaction was that Baez was talking about String Theory, but upon reflection this is not true, he was talking about everyone. There is new and surprising data from cosmology and by the large the theoretical physics community is ignoring it.
Mostly because nobody seems to have a clue how to handle it...

WRT to the investment in QM or GR I stand with Rovelli:
http://www.edge.org/q2006/q06_9.html#rovelli

"There is a major "dangerous" scientific idea in contemporary physics, with a potential impact comparable to Copernicus or Darwin. It is the idea that what the physics of the 20th century says about the world might in fact be true."

 

[arivero]

f-h, on the contrary, the most cited works last year are the ones about the new results from cosmology, so they are not being ignored. They are even getting new sections in the Review of Particle Properties.

In fact, I would prefer the hep-th and hep-ph communities to forget about these results and to concentrate in particle phenomenology.

As for the rest, I agree that Baez is doing a strong criticism of the (pseudo)mathematization of fundamental theoretical physics, very near to Woit's.

 

[arivero]

Baez attributes the, how shall I phrase it? - stiffness of the string physicists to the usual suspect, pride. But looking at the discussions, and especiallt the comments thread at Not Even Wrong over Smolin's new essay, I suspect there is something that goes deeper. Back to the way physics students are trained, at least in US grad schools.

World wide problem. Students are trained (actually, selected) to solve problems (and to enjoy it). Not to select problems. When students become Peers, the peer-review system reinforces the mechanism.

 

[wolram]

http://www.sciencenews.org/articles/...4/mathtrek.asp

http://arxiv.org/abs/nucl-th/0603028

Two papers worth a glance.

 

[f-h]

Arivero, yes people are aware of it, and there is quite a bit of model building being done, but it seems to me that the people working fundamentaly, in String Theory and LQG have no idea how to read this new data for hints of what's going on fundamentaly.

 

[selfAdjoint]

http://www.sciencenews.org/articles/...4/mathtrek.asp

http://arxiv.org/abs/nucl-th/0603028

Two papers worth a glance.

I don't know which Science News one you meant, and I can't for the life of me see what the second one has to do with this thread.

 

[Careful]

World wide problem. Students are trained (actually, selected) to solve problems (and to enjoy it). Not to select problems. When students become Peers, the peer-review system reinforces the mechanism.

Exactly, and this is the main obstacle to progress in science since we really require NEW physics which goes beyond relativity, QM and how we percieve the other interactions. This is NOT a technical problem as history has proven it:

(a) there exists up to date no theory which unifies electromagnetism with GR - all attempts until now failed (also Kaluza-Klein) - and for a good reason !
(b) QG is really almost nowhere (apart from some technical mumbo jumbo which has been developped in the last 30 years)
(c) We did not properly understand yet - IMO - QED (lots of difficult open problems over there)

Our three most fundamental theories (not only two of them - as is often told) are mutually in conflict with each other. Solving these problems requires young, stubborn PhD students and postdocs which have the liberty to take that risk.

Cheers,

Careful

 

[Careful]

haha, I think SelfAdjoint that you are mistaken: those who cannot accept QM simply have the task to do better (which is possible). I believe that in the end, one will have to be prepared to sacrifice to some extend parts of ALL our cherished theories; and believe me, the damage to QM will be the greatest (although GR will have to go partially out of the window too - cfr problem of cosmological constant).

But one thing is for sure: physics is natural philosopy, a message that has been greatly overlooked in the second part of the 20'th century.

 

[arivero]

Exactly, and this is the main obstacle to progress in science since we really require NEW physics which goes beyond relativity,

Hmm note that the problem is not that they are blocked about new physics and problems, the problem is that they enjoy equally any new physics. If needing to choose, they will choose the one able to generate most interesting problems.

 

[selfAdjoint]

haha, I think SelfAdjoint that you are mistaken: those who cannot accept QM simply have the task to do better (which is possible). I believe that in the end, one will have to be prepared to sacrifice to some extend parts of ALL our cherished theories; and believe me, the damage to QM will be the greatest (although GR will have to go partially out of the window too - cfr problem of cosmological constant).

But one thing is for sure: physics is natural philosopy, a message that has been greatly overlooked in the second part of the 20'th century.

Well certainly this opinion, which grandly dictates what physics may be and do, is pure philosophy! My point is that we know NOTHING about Planck scale physics, and both of our beautiful theories break down there, perturbative quantum physics cannot work there and diffeomorphisms obviously are irrelevant there.

 

[Careful]

Hmm note that the problem is not that they are blocked about new physics and problems, the problem is that they enjoy equally any new physics. If needing to choose, they will choose the one able to generate most interesting problems.

Indeed, the more fashionable and flashy the problems are in a so called ``new´´ approach, the more interest it gains. It is a pitty that most students are not made aware that the deepest and most challanging problems are OLD.

Cheers,

Careful

 

[Careful]

Well certainly this opinion, which grandly dictates what physics may be and do, is pure philosophy! My point is that we know NOTHING about Planck scale physics, and both of our beautiful theories break down there, perturbative quantum physics cannot work there and diffeomorphisms obviously are irrelevant there.

Oh no, you do not need to go to the Planck scale to get into trouble ! As I said, there is no unification between GR and EM, which would have to take place at length scales bigger than the compton length of the particles (10^{-13} metres). And who says that you need to go to the Planck scale to unify GR and QM ? No SelfAdjoint, this is not philosophy at all, this is hard reality. Another one : Newtonian gravity gets already into trouble at the submillimeter scale. These problems already require new physics, the Planck scale is just a smoke gun in order to give the illusion that we certainly did not make a wrong interpretation of the EXISTING data.

Cheers,

Careful

 

[john baez]

To learn quantum physics you have to make a leap of faith.

[...]

And the students who go on to work in high energy particle physics accept this and are invested in it to a great and deeply emotional degree.

Other physicsts - those who go into condensed matter physics or especially those in relativity research, don't have anywhere near so much investment in quantum weirdness, [...]

Actually, a lot of condensed matter physics is based on quantum theory. In classical mechanics, for example, a ferromagnet is strictly impossible - see Feynman's lectures, the section on magnetism. Lots of other phenomena, like semiconductors, superconductors, superfluids, Bose-Einstein condensates, the quantum Hall effect, and quantum dots, are also completely incomprehensible without quantum theory. It's hard for me to imagine a successful condensed matter theorist who hasn't internalized the principles of quantum theory.

The big difference between condensed matter physics and particle physics is that experiments are a lot cheaper in condensed matter physics, so it's easier to test theories.

 

[john baez]

you said it!

Most remarkable about the talk is that it is a stinging critizism of contemporary theoretical physics without actually ever mentioning it. Rovelli called Baez on that asking whether what he had just presented didn't imply that the theoretical physics of the last 25 years was "junk". To which John Baez replied after some hesitation "You said it".

Fabulous talk, if you have the chance to catch John Baez talk about anything at all, go.

Thanks! I didn't like Rovelli's question, which put me on the spot. I didn't want to say "no, physics is doing okay!" But I didn't want to draw such an extreme conclusion from the difficulties fundamental physics finds itself in.

It's quite possible that in the future, lots of current fundamental physics will be seen as junk. It's possible that lots will be seen as visionary. Only time will tell. Either way, I don't have the right to pass any sort of judgement on other physicists, since I've tried to do better and haven't succeeded.

So, after hesitating, I pointed to Rovelli and said "You said it!"

Of course this was meant as a double entendre, since in some moods I completely agree with his assessment. But I probably should have said something clearer, and less cute.

 

[Mike2]

But I probably should have said something clearer, and less cute.

You could have said, "Perhaps it's good in showing us what NOT to do."

 

[john baez]

SA, my immediate reaction was that Baez was talking about String Theory, but upon reflection this is not true, he was talking about everyone.

Right. There are more string theorists than any other sort of people working on "fundamental physics", so I focused a bit more on them. But it's not like there are other people out there with a vastly higher batting average when it comes to predicting the crazy new results the astronomers have been finding. As http://magazine.uchicago.edu/0602/chicagojournal/dancing.shtml" said at a recent Chicago University talk, “All of these things came from measurements that weren’t predicted.”

 

[Careful]

Actually, a lot of condensed matter physics is based on quantum theory. In classical mechanics, for example, a ferromagnet is strictly impossible - see Feynman's lectures, the section on magnetism. Lots of other phenomena, like semiconductors, superconductors, superfluids, Bose-Einstein condensates, the quantum Hall effect, and quantum dots, are also completely incomprehensible without quantum theory. It's hard for me to imagine a successful condensed matter theorist who hasn't internalized the principles of quantum theory.
.

I think Feynman was a bit quick in drawing these conclusions, that is about how indespensible and *unique* quantum mechancs is. Sure, there is something lacking in our understanding of EM, which breaks down at the compton scale of particles. However, one does not need quantum mechanics in order to realize that ! There are pleanty of other means to remedy this situation : for example, a compton scale cure of EM seems to make the strong nuclear forces entirely unnecessary. This is the kind of ``new´´ physics we should be trying out. Personally, I do not understand your attitude: there is virtually no experimental input from gravitation beyond a micrometer (actually one could safely claim that gravitation does not even *exist* there ), we know that EM fails for atomic physics, we know that quantum physics cannot retrieve macroscopic realism (as Legett calls it) without some MWI ghost stories, logically QM and GR are incompatible and the consequences of QM and EM are far from being properly understood. Still (!), you say that in order to become a succesfull physicist, you have to live with the contradictions and just work in your branch (sadly you are right) of interest and not bother about the rest. I thought you were a person working on *fundamental* physics ...

My point is that there are pleanty of alternatives one could try out to match current empirical results. The *real* problem being that any such attempt is instantenously met with criticism like : ``oh but I believe you can reproduce these and these QUANTUM results, but can you also do that and that?´´. When I started my physics studies, it was because I thought that people were *genuinely* interested in looking for a coherent world picture; sadly I must confess that I was wrong - the self protection mechanism being : useless publications.

You say: it is impossible to understand superconductivity, superfluidity etc classically. True, if you do not change classical laws on the compton scale, this is indeed the case (you can also make your theory fundamentally stochastic like in SED, but that does not put you any further in solving the cosmological constant). However, if you ask any expert in condensed matter physics how it works, he/she will give you a *realist* explanation using new compton scale physics. Actually, as far as I know, any new physical effect (like bose-einstein, fractal quantum Hall effect) has been conceived by what you might call semiclassical arguments. Isn't that funny, we think in a realist way and still we give birth to ``exclusive´´ quantum effects :-)) Hence, ...


Cheers,

Careful

 

[marcus]

BTW Baez just dropped in at Christine Dantas blog
http://christinedantas.blogspot.com/2006/03/quantum-gravity-and-standard-model.html
scroll to the nexttolast comment (around #32)
this is off-topic but folks in this thread (Baez talk at Luminy) might be interested in what he says in his comment on Christine's thread about
Quantum Gravity and the Standard Model
(the Smolin paper about braid SM)
pardon the interruption

 

[CarlB]

I'll put my two cents in on what is wrong with physics.

Far from QM having a background issue, I think that relativity went off track when Einstein eliminated the ether and universal time. To appreciate my stance on this requires that you read the following two papers which give a flat space formulation for gravity:

<b>Gravity, Gauge Theories and Geometric Algebra</b>
Lasenby, Doran and Gull
http://www.arxiv.org/abs/gr-qc/0405033
Phil. Trans. R. Soc. Lond. A 356, 487-582 (1998).

The reason I think the above is a step in the right direction is that it makes it so much easier to deal with real problems, for example the charge held near a black hole, discussed in the above.

David Hestenes' comments on the above are here:
http://modelingnts.la.asu.edu/pdf/GTG.w.GC.FP.pdf
http://modelingnts.la.asu.edu/pdf/SpacetimeGeometry.w.GC.proc.pdf

But I am pretty much alone in thinking that the primary problem in QM is the vacuum. To appreciate this requires reading Schwinger's book, Quantum Kinematics and Dynamics. That, and a little Clifford algebra, will convince you that unphysical gauge freedom in the standard model arises from an unphysical (i.e. mathematical) splitting of the density matrix formalism into bras and kets. Along that line, note that in 2000, Brown and Hiley extended Bohmian mechanics to density matrices and liked it better than the regular Bohmian mechanics:

http://www.arxiv.org/abs/quant-ph/0005026

Another way of putting this same complaint: The original sin in QM was the factoring of the Banach space to a Hilbert space. Not that it is something that cannot be done, the problem instead is that it can be done in too many ways. The result is that the public is convinced that when you rotate an electron 360 degrees it is somehow multiplied by -1. In the density matrix formulation, this nonsense is avoided.

Carl

 

[CarlB]

It is a pity that most students are not made aware that the deepest and most challanging problems are OLD.

Part of the social problem with physics is that it is taught to people who are 18 to 22 years old. There is a good reason that the military prefers recruits at about that age, and it's not because they have great resistance to being convinced of bullcrap.

The result is that with each new generation, the assumptions of their teachers are entrenched even more deeply. The objections that Nobel prize winners had against iffy improvements to physics survive only as long as the complainers do. The next generation is taught that there is only one way at an age where they are genetically conditioned to believe it. The fact that Schwinger lived to reject QED, that Einstein rejected QM, or that Lorentz rejected relativity are simply ignored. The new generation tends to believe it all because they are told it by people they look up to at a time in their lives when they are very impressionable. The result is string theory.

Carl

 

[Mike2]

Part of the social problem with physics is that it is taught to people who are 18 to 22 years old. There is a good reason that the military prefers recruits at about that age, and it's not because they have great resistance to being convinced of bullcrap.

The result is that with each new generation, the assumptions of their teachers are entrenched even more deeply. The objections that Nobel prize winners had against iffy improvements to physics survive only as long as the complainers do. The next generation is taught that there is only one way at an age where they are genetically conditioned to believe it. The fact that Schwinger lived to reject QED, that Einstein rejected QM, or that Lorentz rejected relativity are simply ignored. The new generation tends to believe it all because they are told it by people they look up to at a time in their lives when they are very impressionable. The result is string theory.

Carl

The cure, of course, is to derive physics from logic itself.

 

[Careful]

The cure, of course, is to derive physics from logic itself.

Oh boy, wouldn't you better figure out first what an electron is before you start such impossible and (frankly speaking) useless quest? Our laws of nature are partially incomplete and incorrect so why take them as immutable in the first place in trying to derive them from something so general that you can go either way? I fully agree with CarlB: most students find themselves already so clever when they master Feynman diagrams and renormalization that they forget that these *tools* are there because of a sick theory. Schwinger recognized this in the case of QED and refused to teach his students Feynman diagrams - actually he did a whole lot more : he developped his own story!

 

[f-h]

Well I am a student, not quite 22 but not to far past that, so I thought I'd respond there a bit.

First of all, those few of us who go on to even aspire to work in foundations of physics, certainly are not those who thought Feynman Diagrams were anything but a clever graphical calculus.

There are many people who are not interested in foundational aspects, to them these tools work just fine as well, and there is lot's of structure to figure out in their context.

All of us know from early on that the realhttp://www.claymath.org/millennium/Navier-Stokes_Equations/" is not in figuring out how to calculate the 4th order terms of the QED expansion though.

But none of us have the hubris to assume you can go beyond what Heisenberg, Einstein, Schwinger, Gell-Mann, Feynman and co did without learning properly what they did in the first place. What we know about the world is compressed into their theories. And thought these theories are defective we need to know what they are saying to go beyond.

It took a couple of centuries from Newton to Hamilton. IMO the most prudent thing to do at the moment is to try to simplify and understand QFT to prepare the soil for future revolutions. We are not at a point in time where a Heisenberg or an Einstein can emerge, because there are no Bohrs and Sommerfelds or Maxwells upon which they could build at the moment.

Furthermore, Einstein and Bohr didn't need encouragment from established physicists to postulate their assumptions which flatly contradicted what centuries had tought before, and if there should be a genius around at the moment, he/she will not need it either. In that sense I think Smolins "No new Einstein" is quite besides the point. (Which doesn't mean I don't agree with the conclusions, but it's imprudent to suggest that these solutions are necessary/good for a new Einstein). They also were driven to it by carefully studying what was there before. If anything we are suffering today from an excess of speculative ideas for the sake of it.
And if anything then to many people are working in some more or less arbitrary exotic new ideas rejecting a more or less arbitrary old assumption instead of bringing order into these very assumptions.

---

Albert Einstein to a student:

Dear Miss - I have read about sixteen pages of your manuscript . . . I suffered exactly the same treatment at the hands of my teachers who disliked me for my independence and passed over me when they wanted assistants. . . . Keep your manuscript for your sons and daughters, in order that they may derive consolation from it and not give a damn for what their teachers tell them or think of them. . . . There is too much education altogether.

http://lib.ru/FILOSOF/EJNSHTEJN/theworld_engl.txt

 

[Careful]

**
But none of us have the hubris to assume you can go beyond what Heisenberg, Einstein, Schwinger, Gell-Mann, Feynman and co did without learning properly what they did in the first place. What we know about the world is compressed into their theories. And thought these theories are defective we need to know what they are saying to go beyond. **

Here I firmly disagree. All you need to know to make progress in physics is calculus, electromagnetism, classical mechanics, fluid and wave dynamics, an introduction to quantum mechanics, special relativity, general relativity, some phenomenological particle physics (and the group theoretical ideas behind the standard model) AND data of the experiments, something theorists have poor acces to (most of us don't even care what the guys in the lab are messing around with anyway - as long as they tell us that the theory is not refuted). What you need to ask yourself is (a) whether these theories are logically compatible, do they share the same physical principles ? (b) if not, how could you modify them so that experimental output is still respected. Learning about Feynman graphs is NOT going to put you any closer in understanding about these gaps in *physical* understanding.

**
It took a couple of centuries from Newton to Hamilton. IMO the most prudent thing to do at the moment is to try to simplify and understand QFT to prepare the soil for future revolutions. We are not at a point in time where a Heisenberg or an Einstein can emerge, because there are no Bohrs and Sommerfelds or Maxwells upon which they could build at the moment. **

Come on, this is utter nonsense: why do you think QFT has the final answer anyway? This theory is far from understood and does not even as such deserve the status of *theory*. All we need is young people with original ideas about OLD experiments, people who do understand that ``something is deeply wrong´´ in the way we think we understand nature.

** Furthermore, Einstein and Bohr didn't need encouragment from established physicists to postulate their assumptions which flatly contradicted what centuries had tought before, and if there should be a genius around at the moment, he/she will not need it either. **

Right, but you do not need to be a genius for doing that, you need to be much more persistent than anyone else. Einstein and company were not smarter than many contemporary physicists, they were just 10 times as stubborn. The cult of genius is a fraud : anyone with a good right part of the brain (say an IQ above 155) and an attitude of ``**** you all´´ could be the next Einstein.


**If anything we are suffering today from an excess of speculative ideas for the sake of it.
And if anything then to many people are working in some more or less arbitrary exotic new ideas rejecting a more or less arbitrary old assumption instead of bringing order into these very assumptions. **

Funny: the assumptions most deviant thinkers today are using are much OLDER than GR and QM together, and therefore are much better established. It are exactly those who do not want to give up both and still want to unify them who are forced into exotism.

**
Dear Miss - I have read about sixteen pages of your manuscript . . . I suffered exactly the same treatment at the hands of my teachers who disliked me for my independence and passed over me when they wanted assistants. . . . Keep your manuscript for your sons and daughters, in order that they may derive consolation from it and not give a damn for what their teachers tell them or think of them. . . . There is too much education altogether.

http://lib.ru/FILOSOF/EJNSHTEJN/theworld_engl.txt[/QUOTE]
**

Indeed, so this nicely contradicts what you claimed in the beginning...

 

[f-h]

All you need to know to make progress in physics is calculus, electromagnetism, classical mechanics, fluid and wave dynamics, an introduction to quantum mechanics, special relativity, general relativity, some phenomenological particle physics "+ experiment"

How are you going to understand phenomenological particle physics without Feynman diagrams?

Come on, this is utter nonsense: why do you think QFT has the final answer anyway? This theory is far from understood and does not even as such deserve the status of *theory*. All we need is young people with original ideas about OLD experiments, people who do understand that ``something is deeply wrong´´ in the way we think we understand nature.

All experiments conducted so far can be understood effectively in the context of QFT.
In so far as QFT makes no sense, the only sensible option is still to study it, see what works, and what therefore must be reproduced by any theory supplanting it.

Newton didn't have the final answer, but he described the world as it is seen. As does QFT. To go beyond Newton it was necessary to understand Newton's theory as deeply as Hamilton and co. did. At that point it became possible to write down a new theory that incorporated the deepest features of Newton that these mathematicians had revealed.

What I was saying is that I suspect that real progress will only be possible once we understand QFT much more deeply.

anyone with a good right part of the brain (say an IQ above 155) and an attitude of ``**** you all´´ could be the next Einstein.

Or more likely the next annoying crackpot. Einstein took Maxwells equations more serious then his contemporaries, not less. The question is whom do you flip off, and whom do you take serious.

Funny: the assumptions most deviant thinkers today are using are much OLDER than GR and QM together, and therefore are much better established.

And in so far as they can not reproduce QM and GR as the theories that summarize real experiments in the real world, they are wrong.
What assumptions are you talking about anyways?

Indeed, so this nicely contradicts what you claimed in the beginning...

I wasn't talking about education, I was talking about learning the old theories. Big difference.

 

[Mike2]

Oh boy, wouldn't you better figure out first what an electron is before you start such impossible and (frankly speaking) useless quest? Our laws of nature are partially incomplete and incorrect so why take them as immutable in the first place in trying to derive them from something so general that you can go either way? I fully agree with CarlB: most students find themselves already so clever when they master Feynman diagrams and renormalization that they forget that these *tools* are there because of a sick theory. Schwinger recognized this in the case of QED and refused to teach his students Feynman diagrams - actually he did a whole lot more : he developped his own story!

Seems I struck a nerve, or maybe this is your normal attitude. But I thought I was nothing more than restating the underlying permise of science - that there is a REASON FOR EVERYTHING. If this applies to everything to the very core of physical fundamental, then isn't that the same as saying that physics can be derived from logic?

I don't know that we are too far from this completion of physics. We already apply the logical union and intersection of sets to get topologies, and we engrave coordinates on them to get manifolds that we use in physics. Torsten is thinking that the curvature of these manifolds gives rise to the algebra of QM. The alternative interpretation of union and intersection used in knot theory might be recognized as a subset of the graphs in LQG or in the latices of CDT, etc. I don't know, but it seems to me that we are getting close.

 

[Careful]

How are you going to understand phenomenological particle physics without Feynman diagrams?

? Just study which scattering processes are observed ! The theories leading to the Feynman diagrams are constructed as to REPRODUCE scattering processes observed in the laboratory.

**
All experiments conducted so far can be understood effectively in the context of QFT.
In so far as QFT makes no sense, the only sensible option is still to study it, see what works, and what therefore must be reproduced by any theory supplanting it. **

If I cut off the Feynman series after the third order interactions, then I am fine with my ``predictions´´, but then the theory is as good as ``classical´´ . Nonperturbative QFT is not understood.

** To go beyond Newton it was necessary to understand Newton's theory as deeply as Hamilton and co. did. At that point it became possible to write down a new theory that incorporated the deepest features of Newton that these mathematicians had revealed. **

Hamilton, Lagrange and CO had a *new* idea (actually you cannot reproduce ALL of Newtonian physics in this way).

**Or more likely the next annoying crackpot. Einstein took Maxwells equations more serious then his contemporaries, not less. The question is whom do you flip off, and whom do you take serious. **

People who have an own world view and can express this in the language of mathematics and predict outcomes of experiments are NOT crackpots, a word which is too often used by physicists who have no ideas themselves. By the way: recently Peter Holland has written a paper in which he considers Lorentz symmetry in EM to be effective and not fundamental. Quite an interesting read even though it is not fashionable !


**
And in so far as they can not reproduce QM and GR as the theories that summarize real experiments in the real world, they are wrong.
What assumptions are you talking about anyways?
**

Who says you need to reproduce QM and GR?? By the way GR is not confirmed : (i) Pioneer anomaly (ii) cosmological constant (iii) dark matter (iv) the analysis of the satelite probe B concerning the Lens Thirring effect is still underway and so on. And who says QM is the only way to explain microscopic phenomena ?? Neither is QFT (apart from the fact that it is not a theory yet) confirmed : (i) the famous Higgs (ii) the illusion of supersymmetric particles (iii) the issue of vacuum energy (if I knew more of QFT phemenology I would probably be able to tell you more).

**
I wasn't talking about education, I was talking about learning the old theories. Big difference. **

Your selection for old seems to be very limited; string theory was also considered as finished in some part of the eighties

 

[marcus]

...
Or more likely the next annoying crackpot. Einstein took Maxwells equations more serious then his contemporaries, not less. The question is whom do you flip off, and whom do you take serious.
...

I don't want to get in the way of this interesting discussion, so I will be very quick. I like this sentence "The question is..."
He showed independence, then, not by disregarding something, but by regarding it more carefully than the others, and his teachers, did.
As I understand what this sentence is saying---the others thought about maxwell equations "well this is just some proceedure that works, like a feynman path integral, but not to take seriously" (except that they did not know path integrals so it is a bad example)
the others perhaps were thinking "these maxwell equations are not fundamental, they are just an approximate computational trick that accidentally works"
So he showed independence by not sharing in the commonplace superficiality, but instead by taking more seriously.
maybe saying "If this works so well, it must be because of some reason."

some people would say that the great majority of theorists today do not take seriously enough the fact that general relativity works----and so they have not taken the trouble to make a general relativistic QFT----they only have made a special relativistic quantum physics----and this might show that they are not being philosophically serious enough

in effect, flipping off the wrong thing. It is a nice way to put it f-h

 

[Careful]

Hi marcus,

My point is that none of the contemporary dogma's is giving satisfying answers : people should realize that our ALL theories are lacking something. Therefore, I encourage people to think out of the box, to try to look at one and the same thing in 1000 ways respecting some logically consistent part of ``old´´ physics; statistics will then tell you that there is at least one scenario which fits all problems. Of course, at least 990 theories will be flawed, but personally I don't care about that. The probability that something decent is produced by standard science does not exceed that number either - just scan the Arxiv for the proof. Highly likely, string theory is only good for mathematics and LQG does not even exist yet as a *physical* theory (why do you think these spin foam models came to stage ?). People who say QFT is the future better start cleaning up the mess first. Who knows what the future will be (my bet is that realism and determinism will prevail again) ?

 

[Careful]

**Seems I struck a nerve, or maybe this is your normal attitude. **

I just always react like that when something that naive is said.

**But I thought I was nothing more than restating the underlying permise of science - that there is a REASON FOR EVERYTHING. If this applies to everything to the very core of physical fundamental, then isn't that the same as saying that physics can be derived from logic? **

I am glad you reject QM, since this will tell you that the reason for everything is magic. Apart from the fact that every modern positivist will contradict your statement, even me as realist has to acknowledge that such persuit is logically flawed. GOD is the first reason for everything by definition - science is the art of finding a mechanism behind that piece of information we have access to. As I said before, science is natural philosophy, there does not exist something like truth in physics.
By the way, we are lightyears away from a theory of everything. No decent physicist will contradict that.

 

[f-h]

Marcus, thanks, yes that's precisely what I meant. As Rovelli recently explained in some detail in a seminar, Maxwells equations were taken to be effective equations of a more fundamental fluid mechanics until Einstein.

Careful, so what's the virtue of saying "if an electron scatters with a myon I get this and that cross section, if an electron scatters with a photon I get this and that cross section..." instead of saying "There are the following interaction vertices and propagators, and all Feynman diagrams contribute".

And actually, according to your mantra, I musn't stop there. I shouldn't talk about photons and so on which are part of nonperturbative noninteracting QFT (which IS understood quite well).

Also predicting "some" experiments isn't enough, you need to explain all the experiments that have been conducted before you. Now there is none that contradicts QM and very few at all that perhaps contradict GR (cosmological constant and dark matter don't contradict GR, and the pioneer anomaly is far to little understood to draw firm conclusions).

On the other hand there are millions of experiments that demonstrate these theories work. Of course you can *in principle* just go ahead and explain all of them in terms of some completely different theory. The sane option is to just show that your theory reduces/produces to GR/QM in some appropriate sense and thus automatically fulfills the experimental tests. (Just as GR becomes SR and SR becomes Newtonian, and QM becomes classical in the appropriate sense)

Knowing the range of validity of experimental tests is of crucial importance of course, see P and CP, which were assumed to be true but hadn't been tested.
Ignoring the theories that organize our knowledge of experiment isn't feasible though. Even the ugly Standard Model is a fantastic reductionist feat, explaining thousands of experiments and ridiculous amounts of data in terms of two dozen parameters (plus of course the millions more that were performed on Newtonian mechanics which is ultimately contained within it). In GR you have fewer experiments but only two parameters either.

The range of validity of our best theories exceeds the range of experiments conducted. Better theories or experiments will eventually tell us what the range of validity of current theories is, but they do subsume all we do know about reality.

With the important exception of cosmology. Which goes right back to the topic of this thread: Baez says "Hey look! Data (of sufficient precision to commence pondering it's detailed implications) that is beyond our current understanding of the world as expressed by GR/SM! Exciting!"

 

[Careful]

** As Rovelli recently explained in some detail in a seminar, Maxwells equations were taken to be effective equations of a more fundamental fluid mechanics until Einstein. **

And who says that was a correct move ? You do not seem to get my point that any view consistent with reality is fine, and that a wealth of views is a RICHNESS for physics.

**
Careful, so what's the virtue of saying "if an electron scatters with a myon I get this and that cross section, if an electron scatters with a photon I get this and that cross section..." instead of saying "There are the following interaction vertices and propagators, and all Feynman diagrams contribute". **

? Nowhere did I claim that *only* knowing particle phemenology is a virtue ! I said it was *sufficient* (modulo some other knowledge) to start doing original work in physics. Example : the preon models, they are not obviously related to the standard model at all ! Actually, no dynamics is presented yet; however to make progress, all you basically need to know is the classical action for the SM and some SM phemenology.

**
And actually, according to your mantra, I musn't stop there. I shouldn't talk about photons and so on which are part of nonperturbative noninteracting QFT (which IS understood quite well). **

Nah, only the non abelian cases are understood up to some level, QED is not. It all depends upon the level of rigor you want from a theory and QFT theorists are usually not very demanding what that is concerned.

**Also predicting "some" experiments isn't enough, you need to explain all the experiments that have been conducted before you. Now there is none that contradicts QM and very few at all that perhaps contradict GR (cosmological constant and dark matter don't contradict GR, and the pioneer anomaly is far to little understood to draw firm conclusions). **

Ahhhrr, when after 35 years the pioneer anomaly cannot be explained, at the moment that it becomes unlikely that dark matter can be predicted from GR, despite of recent admirable attempts, one should draw some conclusions. The cosmological constant is logically either a problem for GR, either for QFT or perhaps even for both. Concerning experiments which do not violate QM, well that is a delicate matter (all depends upon your prior bias and how you decide to make the statistics). By the way, experiments do not violate of confirm a theory so easily in the naive sense you are aiming at. Statistically, you can only express your *confidence* about a theory. The fact that the Higgs is still missing, that no perfect Bell experiment has been achieved, that supersymmetric particles have not been found yet and so on might also be considered as evidence against the theory (although stricly speaking the SM has the luxury to put these parameters wherever it wants to within reasonable bounds).

**
On the other hand there are millions of experiments that demonstrate these theories work. Of course you can *in principle* just go ahead and explain all of them in terms of some completely different theory. The sane option is to just show that your theory reduces/produces to GR/QM in some appropriate sense and thus automatically fulfills the experimental tests. (Just as GR becomes SR and SR becomes Newtonian, and QM becomes classical in the appropriate sense) **

Well one would indeed expect that to be sane (although I firmly disagree that QM has been shown to become classical in any appropriate sense), it is just that this does not work out ! You know, when you have been thinking about fundamental issues for ten years, you probably either:
(i) stop asking some annoying questions and go on with the business (ii) you try something entirely new.

**
With the important exception of cosmology. Which goes right back to the topic of this thread: Baez says "Hey look! Data (of sufficient precision to commence pondering it's detailed implications) that is beyond our current understanding of the world as expressed by GR/SM! Exciting! **

Right, now start thinking about that, really TRY to find a rational answer to the problems and then see after 10 years how you really think about our theories. By the way Baez probably did not mention that our theories do not present a consistent view upon reality - tsssss.

But again, what is your point ? The engineers, those who come up with practical applications, do you really think they make their inventions using QFT or QM or relativity rigorously? Nah, they all use classical or ad hoc calculations. Personally, it seems to be a contradiction to claim to be a physicist while not being hard-core interested in fundamental issues; become engineer then and indeed use just some tools of QFT if you really need it (which is doubtful).

Cheers,

Careful

 

[arivero]

Marcus, thanks, yes that's precisely what I meant. As Rovelli recently explained in some detail in a seminar, Maxwells equations were taken to be effective equations of a more fundamental fluid mechanics until Einstein.

Er... but they are. Abelian U(1) gauge equations, aka Maxwell's equations, are effective equations of broken SU(2)xU(1).

Of course the point is that the new nonabelian gauge equations are still relativistically invariant ones.

 

[Careful]

Er... but they are. Abelian U(1) gauge equations, aka Maxwell's equations, are effective equations of broken SU(2)xU(1).

Of course the point is that the new nonabelian gauge equations are still relativistically invariant ones.

Invariant under the Lorentz group yes, but why see that as such a virtue (only the vacuum needs to be Lorentz invariant strictly speaking)? You know the problems the minimal coupling principle brings along when you try to get relativity in. Therefore, it could be entirely reasonable to construct non relativistic theories formulated in some preferred Lorentz frame, which *are* invariant under the Lorentz group when averaged over the SO(3) degrees of freedom (actually, this is what Holland does). Gravity then would have to be formulated in such a way that the metric is not the dynamical variable.

 

[arivero]

Time ago I read an argument for Lorentz group in terms of stability/unstability. The point being that c->infinity is sort of an "unstable" theory, where any finite value of c is preferable. In the same sense quantum mechanis is more reasonable, more "stable" than a h->0 theory as classical mechanics.

 

[Careful]

Time ago I read an argument for Lorentz group in terms of stability/unstability. The point being that c->infinity is sort of an "unstable" theory, where any finite value of c is preferable. In the same sense quantum mechanis is more reasonable, more "stable" than a h->0 theory as classical mechanics.

Ah, but the velocities are still bounded in this fluid model as far as I remember (don't panic ); in the same way one might consider the de Broglie mass problem for the complex KG field not as a ``real´´ issue. Concerning the stability issue for QM, let's say I agree that a quantized theory can be reasonably *expected* to be more stable (after all, that was the purpose no - although stability analysis is often not done yet) than the *corresponding* classical counterpart. I disagree of course that no realist stable alternative exists, actually it is easy to understand how stable Hydrogen and Helium can be obtained by making suitable compton scale modifications of EM.

 

[f-h]

Nitpick: You missed my noninteracting.

Careful, we are clearly in very different buisnesses, you seem to be trying to come up with a complete consistent explanaition of everything. You are outraged that people are working with incomplete and inconsistent explanaitions.

I'm personally just mostly interested in understanding nature to the best of my abilities. My time and abilities being severly constrained by me being human I thus simply take the theories that all these other people have constructed to the best of their abilities to describe how nature behaves and work from there, incomplete and inconsistent as they may be, they combine and contain everything we know about nature so far (minus cosmology).
Luckily for me all we know about nature is formulated in two conceptionaly very different theories. So for a conceptional thinker there is a reasonable case to be made that by studying the conceptional dichotomy and seeing if it does imply true incompatibility or if it suggests some subtle change to the concepts we use to do physics.

For this change in concepts new ideas certainly are valuable, and there are many many around. BUT there are some concepts that are at the core of the best theories we have: QM and GR. These theories are unique in the simplicity with which they reproduce an incredible number of experiments, other theories and concepts might be able to do so to, but (for those I have seen) they are *all* *significantly* more complicated then the theories built on these concepts.

Now GR is instructive, it says location is relational wrt dynamical entities. This was the philosophical point of view held at the time of Newton, against which Newton put his principia.
To Newtons contemporaries absolute time and space made no sense. Then for a couple of centuries we got used to it until Einstein realized that the old concepts were right, that there is no absolute space and time, just the local configuration of the gravitational field, and that the conceptional advance of Newton to introduce absolute space time was fruitfull because we live in a particular largely non dynamical gravitational field the physics of which can be absorbed into the background structure of our theory.

Newtons conceptional advance therefore was *real* significant and included deep information about physics, which were only fully revealed centuries later, and only after Maxwells equations revealed additional structures of nature.

Yes some of the concepts underlying GR/QM are likely wrong. But the conceptual advances of GR/QM are still the deepest knowledge about physics we have. So I take it as a starting point. If I realize they are not fundamental, I will in any case need to explain why they are effective, since it's a simple empirical fact that they are.

So I don't sound like I'm chaneling Rovelli completely I'll close with quoting Wittgenstein (emphasize mine):

http://www.kfs.org/~jonathan/witt/t634en.html"

So too the fact that it can be described by Newtonian mechanics asserts nothing about the world; but this asserts something, namely, that it can be described in that particular way in which as a matter of fact it is described. the fact, too, that it can be described more simply by one system of mechanics than by another says something about the world.

 

[Careful]

**Nitpick: You missed my noninteracting.**

Did I ? Who cares about noninteracting theories, these are not physical anyway.

** Careful, we are clearly in very different buisnesses, you seem to be trying to come up with a complete consistent explanaition of everything. You are outraged that people are working with incomplete and inconsistent explanaitions. **

No, I am not. I just react as a difficult person to (a) those who are expected to do fundamental physics and are just messing around in the conservative pool of inconsistency (b) those who are not doing fundamental physics but still claim that everything is fine (c) those who label intelligent people who really try something different - for good reasons - as crackpots. I understand that lab physicists are happy with the Feynman toy, but then just don't attribute anything more to it.

** I'm personally just mostly interested in understanding nature to the best of my abilities. My time and abilities being severly constrained by me being human I thus simply take the theories that all these other people have constructed to the best of their abilities to describe how nature behaves and work from there, incomplete and inconsistent as they may be, they combine and contain everything we know about nature so far (minus cosmology). **

Come on, don't react like this. All of us are just human, Einstein, Schwinger and the rest included... But reading from your attitude (not everyone is the same) why don't you stick to a conservative topic which is certainly worthwhile like particle phemenology, or something in statistical mechanics or solid state physics ? You want to spend your time on LQG which is most probably not a good investment ...


**For this change in concepts new ideas certainly are valuable, and there are many many around. BUT there are some concepts that are at the core of the best theories we have: QM and GR. These theories are unique in the simplicity with which they reproduce an incredible number of experiments, other theories and concepts might be able to do so to, but (for those I have seen) they are *all* *significantly* more complicated then the theories built on these concepts. **

QM is a conceptual disaster, and GR is certainly not easy at all : the non-linearities involved are not well understood and only very special classes of solutions are known. But I told already somewhere that GR and EM are also not unified yet (even at the classical level); so there are many more problems around than just QM and GR (which is what some people want you to believe).

**Now GR is instructive, it says location is relational wrt dynamical entities. This was the philosophical point of view held at the time of Newton, against which Newton put his principia.
To Newtons contemporaries absolute time and space made no sense. Then for a couple of centuries we got used to it until Einstein realized that the old concepts were right, that there is no absolute space and time, just the local configuration of the gravitational field, and that the conceptional advance of Newton to introduce absolute space time was fruitfull because we live in a particular largely non dynamical gravitational field the physics of which can be absorbed into the background structure of our theory. **

Of course - as relativist I understand this beauty - but is also entails lots of difficulties even just in combination with EM. The problem is the right hand side of your equations and in particular the minimal coupling principle used to construct the energy momentum tensor. Really, take a look at Weyl gravitation and Finsler approaches to the unification of GR and EM and you will see that they either contradict observation or either violate causality (the same for Kaluza Klein btw).

**
Newtons conceptional advance therefore was *real* significant and included deep information about physics, which were only fully revealed centuries later, and only after Maxwells equations revealed additional structures of nature. **

Sure, physics was just philosophy before, he introduced the math and the dynamical laws.

** Yes some of the concepts underlying GR/QM are likely wrong. But the conceptual advances of GR/QM are still the deepest knowledge about physics we have. So I take it as a starting point. If I realize they are not fundamental, I will in any case need to explain why they are effective, since it's a simple empirical fact that they are. **

Ah, I challange you - just for fun - to try to find classical mechanisms (short scale modification of known theories are allowed - nobody checked them anyway beyond a micrometer) behind the fundamental experiments which claim that QM is necessary. I expect you at least to come up with a few experiments where you can tell : hey this I can explain without magic.

Really, no hard feelings, why do you want to do LQG ? I feel you are somehow interested in fundamental issues, but on the other hand you don't know what to do (don't worry if I knew what I know now, I would not have done 1/5'th of what I have done in the past )

Cheers,

Careful

 

[Hurkyl]

I have to ask.

What is "magical"? What makes QM magical, but not classical mechanics?Why is magical a bad thing?

 

[f-h]

Oh but I'm happy to be a conservative fundamentalist. Uhmmm... in terms of physics that is.

The paragraph "All I want to do..." wasn't meant entirely jokingly. I think we just disagree what's most "fundamental" or "deep".

Why LQG? I have always maintained that (up to a certain point where the subject becomes to young) fundamental physics is one of the few things that get simpler the further you go. There are less and less concepts to contend with, computational complexity is replaced by conceptional subtility. Complexity is emergent and the simplicity is hidden by the concepts that seem natural only from the incidental perspective of creatures whoes concepts were formed to deal with the particular pocket/scale of stability in the emergent chaos which they occupy.

Michelson Morley is a strange experiment, Lorentz and co did a lot of complicated stuff to describe it, and who knows, perhaps they could have succeeded, but Einstein realized that there is a much simpler way if we change the fundamental concepts.

Sure you could do all of gravitational physics in terms of PPN gravity, but again, Hubbles findings will look strange and complicated.

Sure I can construct non local guiding waves or even more natural models for the double slit experiment, but again, the concepts of QM, self contradictory as they may be, are simpler.

The standard model and QFT are unfinished. They are not simple yet. Which is why i was saying before that this is perhaps the msot important thing to do at the moment: Figure out what the proper concepts are that render the SM+QFT simple.

String theory has given up on simplicity.
But LQG on the other hand is a great example for simplicity. The spin network theory they arive at is extremely simple. As Smolin said in one of the lectures, "You wouldn't believe you could do physics with that, would you?"

That's of course just a teaser. There will need to be more and greater simplicity.

But if there is no simplicity in fundamental physics I'm not interested. If it's going to be complicated fundamentaly then I'd do statistical physics/complexity/emergent phenomena. Not as sexy but great conceptional challenges as well and the added bonus that one actually knows one is talking about reality.

 

[marcus]

as a side remark. In my experience when people criticize LQG they often have something static in mind---something according to some book or some article which they have read and say "ahah! that is LQG" but it is changing. the whole field is a number of moving targets.

I was reminded of this yesterday while watching Smolin lecture #15. this is where he quantizes general relativity----the earlier lectures develop various toy models and the classical theory, so this lecture is the first exposure to actual LQG. And it was different! the connection was not defined at points, with values in a Lie algebra, but was defined on curves, with values in the group. maybe that is familiar to you, but this is an introductory course. The treatment in the Lectures is different from what one would have gotten in the 1990s, or even a few years ago, I think.

maybe teaching something also helps to make it simpler---the challenge of having to explain to new people

BTW I liked very much some of what f-h said about evolution of human's understanding of nature

 

[Careful]

** Michelson Morley is a strange experiment, Lorentz and co did a lot of complicated stuff to describe it, and who knows, perhaps they could have succeeded, but Einstein realized that there is a much simpler way if we change the fundamental concepts. **

Haha, even Einstein's theory of general relativity contains an ether like aspect. But I am not doubting the correctness of the Lorentz invariance of the *vacuum*, it simply does not imply at all that our theories need to be formulated in a Lorentz invariant way.

**
Sure I can construct non local guiding waves or even more natural models for the double slit experiment, but again, the concepts of QM, self contradictory as they may be, are simpler. **

Think deeper.


**
The standard model and QFT are unfinished. They are not simple yet. Which is why i was saying before that this is perhaps the msot important thing to do at the moment: Figure out what the proper concepts are that render the SM+QFT simple. **

That is just not possible, we cannot even compute the classical pendulum hanging in a gravitational field exactly. You are fallen for oversimplification.

**
String theory has given up on simplicity. **

Yes, that is the best evidence that something is deeply wrong.

**
But LQG on the other hand is a great example for simplicity. The spin network theory they arive at is extremely simple. As Smolin said in one of the lectures, "You wouldn't believe you could do physics with that, would you?" **

But Smolin is correct : it hasn't anything to do with physics yet! You seem to have no idea whatsoever of the very DIFFICULT problems any such approach is facing, but I am sure Smolin will only speak about that once you can play around with spin networks (and even then).

**
But if there is no simplicity in fundamental physics I'm not interested. If it's going to be complicated fundamentaly then I'd do statistical physics/complexity/emergent phenomena. Not as sexy but great conceptional challenges as well and the added bonus that one actually knows one is talking about reality. **

Sure, I agree that simplicity as well as conceptual clarity and beauty are fundamental requirements; but I am afraid that LQG does not pass the test.

 

[Careful]

**
this is where he quantizes general relativity----the earlier lectures develop various toy models and the classical theory, so this lecture is the first exposure to actual LQG. And it was different! the connection was not defined at points, with values in a Lie algebra, but was defined on curves, with values in the group. maybe that is familiar to you, but this is an introductory course. The treatment in the Lectures is different from what one would have gotten in the 1990s, or even a few years ago, I think.
**

General relativity is NOT quantized in LQG, that is simply false. LQC of Bojowald is an entirely different matter, but that is *not* quantized gravity.

 

[Careful]

I have to ask.

What is "magical"? What makes QM magical, but not classical mechanics?Why is magical a bad thing?

The measurement and entanglement are magical. If you do not understand why or want to come up with some mathematical arguments why I should not care, save yourself the effort (I probably know it already). QM is the instantaneous reintroduction of Newtonian ideas after Einstein developped relativity.