Wednesday, August 02, 2006

Lee Smolin's Trouble with Physics

Last night I had a nightmare! Bigfoot knocked at my door and wanted to talk to me about the existence of the string theory landscape. Still on east-coast time, I wiped off the sweat from my forehead but couldn't fall asleep again. I switched on my laptop, and decided its time to post the review on Lee Smolin's new book.

Last week I surprisingly received an email from his publisher who apparently doesn't mind me posting a review on my blog before the book is officially published. It seems the publisher's strategy is that every publicity is good publicity. Given the comments I had on his book, I can't say Lee looked very happy when I told him I'd write the review. So I thought it would be a nice gesture to let him add some comments.

Anyway, since most of you haven't yet had a chance to read the book, I don't see any point in picking at details which I didn't like (there were plenty). So instead, this is more of a general summary of the book's content.

However, I want to point out that I did not read the final version and that some sections might have changed in the last revisions.

The Trouble With Physics

The Rise of String Theory,
The Fall of a Science,
And What Comes Next

Lee's book analyzes the present stagnation that we experience in theoretical physics with the intention to understand its cause, and he proposes a strategy to ameliorate the situation. For this purpose, the presently most pressing problem in the US in investigated, that is the dominance of research by string theory, or better, the string community.

Even though the string community's lack of self-criticism is the obvious center of concern, the aim of the book goes far beyond confronting string theorists with the problems of the 'real world out there'. Building up on his examination of the current situation, Lee argues that the way scientific programs and researchers are supported today is inefficient under the present circumstances.

After some philosophical detours about the ethic of science, he eventually concludes with concrete proposals.

    (From the introduction:)
    "Why is physics suddenly in trouble? And what can we do about it? These are the central questions of my book."

The book is divided in four parts

Part I: The Unfinished Revolution
Part II: A Brief History of String Theory
Part III: Beyond String Theory
Part IV: Learning From Experience

The first part introduces the reader into the big five problems:

1. The problem of quantum gravity

2. The foundational problems of quantum mechanics

3. The unification of the particles and forces

4. The values of the free constants in the standard model

5. Dark matter and dark energy.

The following chapters then examine how historically great problems have been solved, what challenges have been met, and what detours have been made on this way.

The scientific level is easily accessible for anyone with an interest in the subject. It is a fascinating history from Kepler's laws over Maxwell's unification of electricity and magnetism, via Einstein, Kaluza and Klein's idea of extra dimensions to the quark model, Yang-Mills theories, and towards the Standard Model. Two chapters are about the so-far unsuccessful searches for further unification (grand unification, technicolor, preons, supersymmetry...), and one further chapter is dedicated to the problem of quantum gravity and background independence.

These chapters also provide the reader with a basis for the following parts and make the book fairly self-contained, though it is not recommendable as an introduction into the Standard Model or General Relativity on its own.

The second part briefly summarizes the ideas behind string theory, the problems that come along with it, what has been done to accommodate the problems, and what further problems followed.

By reading this history of string theory, it became clear to me why so many physicists were drawn towards string theory and its promises. It is a story full of surprising insights, successes and drawbacks.

But most of all, it is an unfinished story.

This part of the book is a very carefully written investigation of the achievements of string theory, and its failure to explain nature. It is a sometimes funny, sometimes sad description of the search for answers to the big five problems, whose pursuers lost their goal out of sight.

Subsequent chapters are dedicated to the first and second string theory revolution, and to recent developments in AdS/CFT, brane world scenarios, KKLT, the landscape and the unavoidable anthropic principle. The part ends by evaluating the insights string theory has allowed us into the big five problems from part one.

The third part of the book then leads the reader through alternative research strategies to approach the big five. It introduces very recent developments like deformed Special Relativity, theories with a varying speed of light, modified Newtonian dynamics. And Lee wouldn't be Lee if there wasn't a chapter about Loop Gravity. He briefly mentions non-commutative geometries, causal dynamical triangulation, as well as twister theory:

    "Plainly, there are different approaches to the five fundamental problems in physics".

It is exactly the part that I found missing in Peter Woit's book. Even though I could not avoid having the impression that the evaluation of promises and drawbacks in this part is less careful than in the previous part about string theory, it is an exciting journey! Unfortunately, it somewhat fuzzes out towards the end where Lee argues that "we have to find a way to unfreeze time".

Though Lee told me that this part of his book is considerably improved in the final version, it still seems to me that these chapters are the optimist's antidote to the depressing conclusions from the previous part. As such they fulfill their purpose very well for the layman, who wants to get a glimpse on the variety of approaches by which we try to reveal nature's secrets. Those working in theoretical physics however, will be left with the desire for more details, and I hope that Lee's book succeeds in sparking a vivid discussion, as well as a critical evaluation, of string theory and the mentioned alternatives.

The fourth - and in my opinion most important - part then analyzes why and how science works best, what sociological problems we face, and under which circumstances research flourishes best. It addresses the problem of groupthink in the string community, the disastrous low-risk-attitude of current funding, and the inefficiency in hiring decisions when it comes to preserving diversity. Lee points out that many of today's research strategies might have been appropriate some decades ago, but do now hinder progress. Political pressure on young as well as senior scientists has grown to become a reason for concern. He concludes in a summarizing chapter What can we do for science with a plea for open-mindedness and "intellectual freedom".

Lee tells a story of a frustrating time, of waiting, but also a story of hope. It's a story told by someone who knows what he is talking about, someone who has a vision, and who doesn't get tired repeating and fighting. Fighting for science to stay scientific.

It's a book that speaks of Lee's dedication for his work.

And I guess it wasn't an easy book to write, given the necessity to criticize what many of his colleagues and friends work on, and what he has worked on himself.

    (From the intro)
    "I can only insist that I am writing this book not to attack string theory..."

There is no doubt that a big part of the book is a criticism of string theory. However, regarding the current situation, this was probably unavoidable. The last part of the book makes clear that its a constructive criticisms, and it sets a starting point for a scientific discussion about the future of theoretical physics.

It is a book written by someone who is deeply concerned about the future of theoretical physics. It is also a book by someone who clearly sees the mistakes made, even though the presentation is not always that clear. The book lacks structure in the 3rd and 4th part, and it requires a certain amount of patience to follow through some of the excursions. But many anecdotes and analogies make the book an entertaining read, and for a popular science book it is indeed very nicely written.

I am afraid this book will make many people who work on string theory and supersymmetry very very unhappy. But it will certainly influence those who currently consider going into theoretical physics. Maybe most important, it will encourage those who are frightened by the prospect to either give up their dreams, or to end up unemployed.

I absolutely don't like the cover. The color choice is awful and the motive makes me wish I could knot up the strings to loops, such that whoever still wears shoes like this realizes his bad taste in clothing.

I can't tell you anything about the figures, except that there are some. In my version, the figures typically look like this: [[Figure 2: Query author, which picture is to be used?]]


Some years ago I was traveling through South Africa. In one of the first guest houses where I stayed, the lady of the house asked me whether I had seen Bigfoot. She spoke a very strange accent, so it took me some while to figure out she was actually asking whether I had seen the 'big five': lion, elephant, buffalo, leopard, and rhinoceros.

We are scientists. We should not loose the big five out of sight because we are searching for big foot's footprints in the landscape.

TAGS: , ,

Notes added:

Update Sep. 19th 2007: The Trouble With Physics: Aftermath

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  1. Does string theory postulate or ignore the Equivalence Principle?

    Do all local centers of mass in String Theory vacuum free fall identically regardless of composition and mass distribution? Which is it, EP or no EP? If EP, say "EP." If not EP, provide an EP-violating example.

    I cannot imagine a more fundamental question. Is String Theory an internally inconsistent exercise in indeterminate mathematics? 10^500 acceptable vacua don't arise out of nothing. They arise out of weak founding postulates.

  2. Hi uncle,

    somehow this question sounds familiar. Didn't I read that yesterday on Lubos' blog? Can I conclude from this question popping up here that he didn't answer it?

    Anyway, I have genuinely no idea how ST would say anything about vacuum (vacuum?) free fall (gravitational background?) of strings. I am also not sure what the EP would look like for extended objects (even classically) instead of point particles, you might want to take this into account.

    One way or the other, I kind of suspect that you can probably find some versions of string theory which do whatever you want them to do. I am actually waiting for someone to claim string theory can imply a DSR or a varying speed of light.

    Can you give me a hint what your question is aiming at?

    And btw, what does this have to do with the post above?

    Best, B.

  3. Hi bee,thanks for pinging me.
    I know you have pointed out that there is not anything new in the book of interest to advanced physics or research.
    I also note that whilst physicist think that science should be apolitical, and conclusive physics is - we are talking about theoretical physics, and theoretical physics is as political as you can get:
    (a) for the obvious reason that there is more than one opinion or possibility, and not all roads appear to lead to Rome.
    (b) the no less obvious competitiveness for research funds, and theno less competitive quest for nobel prizes, fame, kudos in the research community, credibility, personal ego, vanity et al
    I could add more to the list but those two I think pretty much encompass all and (b) is but a part of (a).
    The question always seems to revolve around human emotions. Once before you have mentioned that one would need to be 'inhuman' to transcend human emotions, limits or actions and reactions (and backreactions?).

    So let us be unemotional or try to:
    (1) Does it matter that gravitational forces may be shown to be magnetic forces in 'disguise'

    exactly, there is an immediate emotional or human reaction to those very simple terms, but is there any 'real' contradiction under than I say tomato you say tomatoe

    (2) What in 'essence' would string theory prove or disprove, since by enlarge string theory to evolve into a credible theory has to meet all the criteria imposed on it primarily by the 'laws of physics' as contested by all other theories.

    And again let us not get emotional there are some string theories which are to the far left and some to the far right of the 'political' spectrum

    (3) Dark matter, dark energy and black holes, have not even been clearly defined. The terms have become so ambiguous that people can get emotionally hysterical arguing about points ill defined - again I say tomato you say tomatoe.

    (i) Does a black hole evaporate? - a blackhole in this case clearly meaning or being a singularity
    (ii) Does a singularity lead to other dimensions? - can splitting an atom (in electron formation) lead to creating new electrons, protons and atoms if they find a new nucleus.
    (iii) Is a singularity a high density small volume mass that attracts matter, whether it is by gravitational pull or magnetic force, is still ultimately either the same question that was posed in (1)
    (iv) separating the wormhole like blackholes or tunnels (like the channel tunnel) which may exist in space as tunnels from one place in space to another - from the blackhole or space where a star peviously existed and which now has a singularity which either evaporates or is condensed to such high density than in the vastness of space would appear like searching for the proverbial pin in a haystack, or indeed the proton inside the nucleus of said black-hole.
    (v) remnants of evaporated black holes ... I'll pass that one on to you Bee

    There is no reason why (i,ii,iii,iv,v need to be hotly contested since in the multiple possibilities of the universe and vastness of space there is more than enough room for them all, and less time or hot air (breath) should be spent (wasted) on arguing among each other, andmuch more effort and energy into resolving the possibilities of one and other, and how they may well be interacting to create apparent necessary anomalies in rival theories.

    And finally the Landscape theory is a 'model' and needs to be clearly re-written, does this mean you do not travel to other parallel universes thru blackholes or singularities???
    Well, I never conceded that there were other parallel worlds or universes as perceived by either Leonard Susskind or Lee Smolin in the first place.
    As I've stated before my view is that by definition all possible universes converge [IN] this one universe, the other lifeforms are under our noses, and the other places with different physical laws are just round the corner, they are called 'planets' in our solar system, stars and other galaxies in our universe. Of course from here as observers we still only see a part of that universe as delimited by the 'event horizon' another term in itself which has been used all to often to refer to widely differing events or phenomena.

    So not wishing to rant too long, but rather wishing to invite people to read your well thought out and versed comments, and further to read the book and draw their own conclusions, which can only continue to be opinions or theories, until final conclusions are reached. And it could still turn out then that as with the event horizon the goal posts move again, and when we find or define one law we then look for what is beyond - even I may add when we reach the end of the universe, almost by definition we shall only have just begun.

  4. Hi Quasar,

    still trying to figure out what technorati is good for...

    I know you have pointed out that there is not anything new in the book of interest to advanced physics or research.

    That's a misunderstanding. The book is definitely of interest also for advanced physics or research, just not because of the splendid review of dsr/vsl/ncg/etc. For this, you will have to look up the refs and/or wait for another book. It is of interest for the reasons

    a) it is a long overdue, and badly necessary, investigation of the way science does and can work in the 21st century, and

    b) gives a sensible review on the status and outcome of string theory during the last decades

    Besides this, the question whether a black hole evaporates or not does imo not depend on the presence or absence of the singularity. What does depend on that however, might be (careful, careful) the way it evaporates.

    All the best,


  5. Lubos has no answer! String Theory both postulates (achiral components) and ignores (chiral components) the Equivalence Principle. Trajectories cannot be simultaneously parallel and non-parallel. String Theory for all its elegant duals cannot be correct as assembled, hence 10^500 acceptable vacua.

    Lee Smolin's cover illustration is eerily prescient. If the EP is not postulated, (metaphoric) left and right shoes vacuum free fall along non-parallel minimum action trajectories. They differently fit into a left-footed chiral pseudoscalar vacuum background. Socks (achiral mass distributions) fit like left shoes.

    Physics assumes all local mass distributions default to single points in vacuum free fall. This has never been tested with chiral mass distributions that must have an emergent scale. Chiral crystal lattices cannot be chiral at scales that include fewer than four atomic nuclei. Parity divergent mass distributions do not reduce to points.

    Test #1: 90 days in a $2 million Eotvos balance contrasting ~20 gram solid single crystal spheres of left-handed and right-handed quartz. Expensive and difficult to schedule.

    Test #2: 2 days in two commercial calorimeters contrasting enthalpies of fusion of ~20 milligram solid single crystal spheres of left-handed and right-handed benzil vs. time of day and geographic orientation (less than $(US)100 in consummables),

    String theory does have a falsifying observable. General relativity has not been thoroughly tested. The sweet spot for performing parity calorimetry tests is 45 degrees latitude. The Perimeter Institute is at about 43.5 degrees latitude.

    Somebody should look. No theory can survive empirical falsification.

    (Biomass is chiral. If there were a chiral vacuum background, where is the parity Nordtvedt effect showing a lunar laser ranging periodic anomaly between Earth and moon orbits around the sun?

    The Earth masses 5.9742x10^24 kg. Wet biomass is 3.6x10^14 kg. Water is not chiral. All chiral protein amino acids are L-configuration and all natural sugars are D-configuration. For (dry chiral biomass)/(total Earth mass), meat and wood cancel. No anomaly is detectable above noise.)

  6. Hi Bee,

    A very nice description of the contents of the book, and a very interesting interview with Lee!

    I didn't get the five animals first, but big/foot/five - that's great!

  7. Hi uncle,

    You trying to say right handed molecules (DNA?) have a different grav. interaction than water? Maybe. Yeah, someone could look. But I have no idea what thats got to do with ST? It either has the SM, or it doesn't. If it doesn't, there are probably easier ways to look at this.

    Physics assumes all local mass distributions default to single points in vacuum free fall.

    Not true. You can look at motion of extended and/or spinning objects.



  8. ... can we just do Eotvoes by comparing one ton of left handed, and one ton of right handed yoghurt? And would Nestle sponsor that?...

  9. Great interview and review. I think I might actually pick it up.

  10. And I crave yoguhrt now.

  11. Hi Bee, I don't think it is Technorati I need the help with, however if you'd like to install an RSS (or other) feeder for me maybe I'll get it up and running.
    I did notice a trick of the light and several other strange phenomena, correction physical activity on my Technorati links last night, which included links to the Whitehouse and your article on black holes the band.
    Don't tell anybody, but it cost a certain young lady who ended up getting the ruff end of the 'stick' a hot date - ahh well ciest la vie mon ami - lol!

    I did not misinterpret you in any way. Not that it is of no interest to serious physicists and on going research, but that it offers nothing new. Every read is a good read, even the bad ones.

    On this evaporation thing, trying to catch your serious side for a moment. We need to distinguish what you are hoping to learn from possible evaporation in colliders, which is one thing -
    and cosmological evaporation.
    Remember cosmological 'evaporation' does not require (inply) the instant end of existence of the singularity. They could be like solar flares or even cryovolcanics on Enceladus, ie an almost endless(?) albeit finite process, before something (in cosmological timescales) is again turned into something other in the cycle of particle life.

  12. Bee, forgive the fact that I have not read all of your post(read the interview, great questions and answers), but the cover off Lee's book made me smile greatly.

    All tied up, implications to tread carefully? order to proceed one has to either :

    1)Untie your lace's/strings!

    2)Learn to walk not run!

    3)Jump instead of Walk!

    4Wear wellingtons instead of sneakers !

    5)To know the landscape ahead, one has to prepare one's footware, thus if your going to climb mountains without ideal boots, dont blame the manafacture when you slip and fall from a great height?

  13. DNA or amino acids or cellulose won't work, or yogurt or Kobe beef, or small platinum balls and carbon fiber struts. chemical chiralities are based upon composition and deficient geometry, below. The balls lack self-similar aggregation (not discussed here). If the parity calorimetry experiment in benzil gives a reproducible signal, the vacuum is anisotropic and chiral.

    If the EP has a parity anomaly: General Relativity has two falsified founding postulates, angular momentum is not conserved for opposite parity bodies, string theory loses its achiral components and most of its 10^500 acceptable vacua. How is that for two days' scut work in a chem lab? No prior observation is contradicted.

    There is helicity (depends on POV), chirality (by composition or geometry; non-superposable reflection along one coordinate axis) and parity divergence (chiral divergence in all directions simultaneously). We know by observation that all compositions of matter and masses of bodies obey the EP. Quantitative parity divergence must start by assuming all atoms are anonymous unit masses. Most "chirality" disappears. Gravitation doesn't see electromagnetic chemical bonding, either. All we can build are 3-D arrays of isolated anonymous unit masses in space as self-similar crystal lattices.

    Normalized quantitative parity divergence can be explicitly calculated for a body with countable atoms and finite moments of inertia given the atoms' relative coordinates,

    I found a small error in Dr. Petitjean's software when I composed the first perfectly chiral molecule, CHI=1 for its carbon skeleton, [6.6]chiralane. NIST rewrote its commercial stereochemistry assignment software.

    QCM needs about a server-day to calculate CHI and graph theory diagnostics for 1100 atoms. For the singular fully degenerate COR=1 DSI=0 case, that can be increased to 30 million atoms/second in a PC including crystal lattice growth. We've calculated about 40 crystal lattices at increasing radii. Opposite parity space groups P3(1)21 and P3(2)21 always score CHI rapidly asymptotic to CHI=1 with increasing radius,
    quartz The rightmost point is 4.44x10^17 atoms. long_double_precision calculation

    That is not noise. That is true CHI variation with radius as the sample sphere expands within an anisotropic crystal lattice and changes moments of inertia. (Cinnabar has a subtle symmetry deficiency.)

    Benzil is achiral molten, in solution, gas phase, and burned. It is reversibly deformed and stacked into homochiral helices within its crystal,

    Melting does not racemize the crystal. Melting destroys its parity divergence entirely. If inertial and gravitational mass diverge in opposite parity benzil crystals, both masses must be identical in the melts. A 10^(-13) difference/average mass divergence is an 8% relative enthalpy of fusion difference, E=mc^2, at 95 C.

    It is the perfect experiment to probe for a chiral pseudoscalar vacuum background - cheap, fast, definitive, reproducible at will in common commercial equipment. Typical 0.1% calorimetry precision delivers 3x10^(-18) difference/average mass/mass sensitivity. If there is still doubt, do the parity Eotvos experiment in quartz.

    I greatly respect theoreticians for their eldritch abilities. Theory is meaningless if it models what does not real world obtain. Folks should get off their duffs and do the parity experiment. 50% chance of either outcome. Metric and teleparallel gravitation are otherwise indistinguishable. Nobody has ever looked.

    Modern physics hates experimentation. It must be held accountable for its predictions. Thanks for the real estate to continue the discussion. "8^>)

  14. Oops missed the relevant title:

    The Rise of String Theory,
    The Fall of a Science,
    And What Comes Next?

    What comes next?..some trip and fall maybe?

  15. now thats the first review I see on Lee's book... convinces me to get it asap... he says the right things at the right time... i just hope people listen...

  16. Hi Uncle,

    I'd appreciate if you wouldn't pursue your topic further in this comment section. Thanks,


  17. Although there are things about string theory that irk me, I am sometimes tempted to let theorists do what they want while I go about my own business. (Getting detectors up and running for next year, and all those boring details.) I tend to think there are more models to be built, and tested, before any of the fundamental questions can be effectively worked on from first principles. But perhaps this will be a good read to get a perspective on how string theory affects other paths toward progress in fundamental theory.

    In any case, this was a very informative review. Thanks!

  18. Interesting that you chose a leopard for dark energy....when I went to Africa, my guide spoke of the "Big Four". Why not 5, I protested. "Because you aren't going to see a leopard".

    By the way, having just come from Cosmic Variance, I think that you should add a sixth Big Mystery: the Arrow of Time.....

  19. Dear Bee,
    mucho gracias for the interview. It sheds a whole new light on the profile I drew of Prof. Smolin, believing he is on a mission to bury string theory! Reading how the book came to be about the 'fall of a science' explains a lot. How did you get the interview? Have you met him? Ciao, TIT
    nice blog, will come back, have to get a blog as well

  20. Dear Uncle Al,

    in string theory, the equivalence principle is a derived fact. It is derived from a more fundamental starting point.

    I am sure that Lee Smolin misunderstands these completely elementary questions as much as you misunderstand them and his book is useful reading only for his fellow ignorants at the bottom of the sea.


  21. Is there any discussion of the current and near future experimental situation?

    Reading the summary it sounds as if the 'progress' we are supposedly lacking ought to come, according to Lee, from theorists, and specifically from 'fundamental' theory.

    What role do experiment and phenomenology have in future developments?

  22. Dear Lubos,

    regarding the fact that you've just judged the book by it's cover, I can't help but wonder what exactly is your threshold for ignorance?

    Dear TIT,

    I certainly did not type all these words in the interview, if that answers your question.

    Dear Thomas,

    if you ask me, we have plenty of experimental facts that theorists still have to explain. Right now, its our side where progress is lacking.



  23. Good Morning B,

    Just surfed in...If Bigfoot proves to be only a large man in a cheap bearsuit, then he most likely surfed to your door upon a sub-Hubble wave from within the Universe. On the other hand - if Bigfoot proves to be genuine, then he most likely surfed to your door upon a super-Hubble wave from outside the Universe.

    Both creatures are probably interesting gentlemen simply wanting to discuss landscape designs with you...

    As far as nightmares and cold sweats are concerned...well...I'm uncertain if this male creature (Bigfoot) from outside the Hubble patch is more fightening than a lot of men from within the Hubble patch. Perhaps you can convince Bigfoot to take a few of these frightening men along with him on his journey back to the Landscape.;-)


  24. It's trivially easy to find fault with science. To understand this, it is valuable to recognize an unusual attitude that scientists and engineers have.

    Most people see a problem and say, "Oh, xxxx, I've got a problem." The scientists and engineers say, "Wooo hooo, I've got a problem!". That is, problems are exciting. Some people work to live. As an engineer, i live to work.

    So, scientists are constantly working on problems. They've found it valuable to talk to each other about them, for example, by writing papers about them. Indeed, they seem to do little else. And these papers are publicly available. Often, they can be obtained while sitting at a desk. Hence the assertion that it is trivially easy to find trouble with physics.

  25. 19 parameters and four fundemental forces,
    Is that all we get? Can't we explore some more.
    Physic future of numerology and scientology
    Take everything we measure mixed in a matrix
    Call the eigen values predictions
    and then we're done.
    Godel rollover and go back to bed son.

    Sorry I just downloaded The Grey Album.


  26. Hiyah Bee,

    like the review and im looking forward to reading lee's book. Liked the big foot analogy, but a warning from sir arthur eddington:

    ``We have found that where science has progressed the farthest, the mind has but regained from nature that which the mind has put into nature. We have found a strange footprint on the shores of the unknown. We have devised profound theories, one after another, to account for its origins. At last, we have succeeded in reconstructing the creature that made the footprint. And lo! It is our own.''

    Tom Marlow

  27. There is trouble in physics all right, which makes this an exciting time to be alive working on a better theory.

    If string theory is a waste of time, it is good that potential competitors spend their lives on it.

    There are no photographs of Bigfoot because, by the time people figure out their new digital cameras, Bigfoot gets bored and walks away..

  28. Dear Bee,

    Very interesting interview with Lee Smolin and entertaining review on his new book. Last week the publisher also contacted me about writing a review. But I am still waiting for the copy. Since I am in Brazil, it will probably take some time to arrive here.

    Best wishes,
    PS- Dear Uncle Al, have you not applied for the FQXI grants?

  29. Dear Christine,

    Uncle Al is an industrial chemist not an academic physicist. News to me! If there were a grant wouldn't there be a faculty member eager to spend it? I'll ask.

    Thank you! "Mix business with pleasure and heat to reflux."

  30. insightaction,

    Your right! Godel isn't dead. He's simply hibernating like a bear. Question: Is this bear hibernating in the forest of the Hubble patch? Or is he hibernating in the forest of the cosmic landscape?


  31. Dear Stephen,

    Hence the assertion that it is trivially easy to find trouble with physics.

    Well, yes, I tried not to comment on the title, but I don't actually share the perception of a crisis. That's why I like to refer to it as the so-called-crisis. I.e. the biggest part of theoretical physics is still neither loops nor strings, and the stringy problems are such a hot topic mainly in the US. I'd recommend some people should talk from time to time to European particle physicists to get their feet back on the ground.

    Anyway, besides the troublesome example with the string community, Lee is absolutely right with his conclusion that science in the 21st century needs to be re-evaluated as to whether it's 'methods' (or absence of such) are still appropriate. Can we really keep on doing science as if the world hadn't changed dramatically in the last decades? Hey, come on, we are scientists, we should be able to figure our under which circumstances our work can be most efficient! But to do so, we need to have a sensible discussion (as opposed to calling each other ignorants, morons or crackpots). I hope Lee's book is a starting point for this.

    Whether you call that a crisis or not, the situation can be improved, and it wouldn't take much besides open mindedness and the ability for self-criticism.



  32. Hi Cynthia,

    *lol* you know, this interview on the radio with Lenny Susskind really did upset me. Should try to get some decent sleep tonight. Maybe there's a parallel universe somewhere in the landscape, where the earth is populated with Bigfoots?

    Hi Lambchop,

    wow, you had a guide! I got lost repeatedly. Worse, I was almost stomped over by an elephant.

    Dear Christine,

    I am looking forward to reading your review. I am really curious about your opinion!

    Dear Tom,

    thanks for the thoughtful comment. You are absolutely right. We should be careful not to fool ourselves with traces that we have left on slippery ground.



  33. Hello B,

    I have to say that the coincidence of this posting as a refresher of what took place in 2004 on the landscape issue I thought important.

    If you highlight the linked words in my post, you get another perspectve of the mouse :) on that.

    Lee's analogies are always interesting.

    there are two kinds of scientists-hill climbers and valley crossers. Hill climbers are great technically and will always advance an approach incrementally. They are what you want once an approach has been defined, i.e. a hill has been discovered, and they will always go uphill and find the nearest local maximum. Valley crossers are perhaps not so good at those skills, but they have great intuition, a lot of serendipity, the ability to find hidden assumptions and look at familiar topics new ways, and so are able to wander around in the valleys, or cross exposed ridges, to find new hills and mountains.

    As a lay person I have benefited greatly from the wise words of John Brockman to Lee Smolin on how he should write so that it is more accessible to the general public.

    Some of us like to dig deeper and how this affects one's look on the landscape really doesn't do much if the book is not in print for the readers.

    A few of us of course have been witness to the many dialogues that have taken place with Lee and others around the internet, so the sense of his response in the form of the book he writes, is from a gathering consensus in "his view" and "synoptic view" of the arena of "scientist discussion" which he is very good at.

    AS a Lay person I am not sure how I will be effected. The Cosmic string issue still vibrates in my

    Like your Bigfoot TOE(theory of everything) analogy.

  34. Nice review. Could you post the review about the 5th
    section on "Dark matter and dark energy"?

  35. Hi Bee, as always you have communicated very clearly for someone like me who doesn't really know much actual physics. I like your 'big 5' animals and their symbolism, but I think this is probably a *female* strength (symbolic/iconic thinking). I hope you sleeping better by now. Have you tried any herbal teas? I like one with passion flower in it. Even if the herbs don't make you relax just the act of drinking a warm cup of it will.

  36. It occurred to me that you might have taken my previous comment in the wrong way. I meant it entirely in a complimentary way. I think that Lubos just doesn't realize how rich and intricate our female 'two dimensional' thinking can be. And I mean this not as an insult to him or any other males. I'm just saying that *because* of his *maleness* he isn't entirely capable of thinking like a woman and therefore truly appreciating all of its best strengths in the same way we experience it. Thinking is just like sex. Men and women will never be able to 'feel' what the other feels 'down there', but it sure is fun trying! ;-)

  37. Hi Bee,

    Thanks. The book hasn't arrived yet. But as soon as it does (and I hope it does), I'll take high priority in reading it and posting on my impressions if I feel I have something new to add. I am out from the main stage where the action is being taken (renowned U.S. or European universities/institutes). To me, the "trouble with physics" is in fact a double trouble.

    Best wishes,

  38. My geologist friend introduced me to the famous "Blind Men & the Elephant" metaphor. Picture the elephant as the "Big Picture" of Physics, & we as observers are seeing only a partial data-set (trunk, tail, ears, side, et al). Each observer sees a different component, & draws incorrect conclusions about the "whole".

    "The whole is sum of the parts"
    "I'm locally pessimistic [ partial data-set ], but globally optimistic [ eventually, we will understand the whole ]"

    I was watching a PBS series on Philosophy, The Examined Life", where they had a couple episodes on Science:

    115) How Does Science Work?
    Highlights the classic, Baconian inductivist view that grew out of the Scientific Revolution and the challenges posed by Karl Popper and Thomas Kuhn. Includes consideration of Kuhn's views about the role that paradigm theories play in scientific revolutions.

    116) Does Science Give Us Truth?
    Looks at correspondence, coherence, and pragmatist theories of truth, and how conflicts have carried over into realist vs. antirealist views of science, including the Einstein-Bohr debate about quantum mechanics.

    My next-door neighbor (history teacher, high school) introduced me to Plato's "Allegory of the Cave". He had brought up the fact that of all the religions, that Buddhism was the "most scientific". Like the "7 blind men & elephant", the "Allegory of the Cave" teaches us we see only partial data-sets. AoC may be very appropriate to ST (& similar theories), since we are seeing "shadows" of projections (sub-dimensional sub-spaces).

    Has anybody in Physics used the terminology "Grand Challenge", & partitioned Physics into some categories of unsolved problems? I've heard of the term in Computing Research. It was also used in the recent DARPA project involving unmanned vehicles, where Stanford, CMU, Caltech, Princeton, UCLA all had teams (Stanford was victorious, BTW). This is an area I'm involved in, Offroad Racing. The Technology I've been playing with was brought to SUSY '06. Talk about a wraparound effect! I was just at Caltech a couple days ago, talking to the Caltech DARPA GC faculty advisor for help with my own project.

  39. "But as Smolin reveals, there’s a deep flaw in the theory: no part of it has been proven, and no one knows how to prove it. As a scientific theory, it has been a colossal failure."

    from book site.

    Is the above a typical science-challenge journalist mistake, or is it actually stated in the book?

    "You can never Prove a can only DISPROVE it"

    [ told to me by my brother-in-law, who's a Developmental Biologist @Emory ]

    Theories are temporal, based on the latest data-set (still incomplete, only partial). Thus, as new data rolls in..they are always subject to modification, & sometimes completely thrown out ("disproved"). Is the optimism behind ST ("it's so beautiful & elegant"), that people are saying it has to be RIGHT (& possibly "proved")? Pretty dangerous do they know something else (another theory) will come along & be "more beautiful/elegant"?

    A well-known galaxy astronomer (Mike Disney/UK) had a very critical paper about cosmological predictions by the NGST (succesor to the Hubble), it's a Signal to Noise problem (Poisson counting statistics based on signal-strength, sqrt (S)). To reach the furthest objects in the Universe via telescopic observation, would require ENORMOUS diameter telescopes (the size of planets, solar systems, galaxies, etc). To illustrate this point, there was an Astronomy conference where the presenter had a slide "It's all about APERTURE, stupid!"

    In another words, there are limits to what size telescopes man can build..therefore there is a limit to what scientists can observe..especially for cosmological scales. We seemed to be doomed to a partial data-set, therfore "no theory can be proved". Isn't it true also with particle accelerators, that there are limits to what energies can be achieved?

    I get the feeling that ST'ists (& any advocate of their pet theories) can get "idealogical" = religious about it, & lose their objectivity. It happened in my area of Research, where I was ridiculed because:

    "how dare I can do it, if THEY couldn't solve it!"

    New Ideas (often by outsiders of a field) are perceived as "heretics" & attacked. Take a look at Wegener ("Continental Drift", which we know today as Plate Tectonics), & how he was mercilessly grilled by the status-quo. I had a conversation with a Caltech geophysicist, & he brought up the historical patterns of Scientific Discovery.

    "Today's tomorrows Theory"

  40. I was in S. Africa in 2002, & Zambia/Botswana in 2001, see here for a "croc munching on a lioness". The "Big 5" was mentioned in Kruger NP by some tourists, it became a "child's game played by adults".

    The challenge was "leopard" (dang lucky to see one), "cheetah" (didn't see one), wild dog (saw some), hyena (saw one). What's not generally known (because of African wildlife shows on TV), is that most predators hunt at night. Also, hippopatumus account for most of the deaths in Africa: they're fast, agressive. As a S. African told me "if you're caught between a hippo & the water..YOU'VE HAD IT". You have to be real careful at water, because lurking crocodiles will "jump on you". Elephants can trample you, & when I was camping at night my guide told me how to use fire to scare them away. I dropped something out of the Landcruiser & was about to hop out & retrieve it. But, the driver said "Stop!", he backed up & I was able to get it. I asked him why & he said "A lion could be lurking behind a bush". Risk Management, being in the bush is like playing poker.

    I think partitioning Physics into some "Big 5" dangerous animals from Africa is a good metaphor, because Science Research is like "walking into a minefield". Without "global perspective", a narrow view in one niche-area ("dangerous animal") can lead to dangerous consequences: making incorrect conclusions about some global issues. The "7 Blind Men & Elephant" is a perfect metaphor.

    In touring Africa, one needs Local Knowledge..a guide who's an expert on a specific area. I was told by a S. African:

    "If you are alone in the City, you will be Robbed..if you are alone in the Bush, you will be Eaten"

    Similarly, for Physics one needs to turn to local-specialists in each niche-area. There's a famous quote about experts ignorant outside of their own fields.

    "We can acknowledge that we know our own fields, but must risk the fact that we are ignorant outside these boundaries. It may likely require an entire generation of scientists to make the transition from a disciplinary to an interdisciplinary perspective. "

    See here

    I like the use of a "map" (by animal metaphor), so a reader can understand where a research paper fits in a landscape of global connectivity. I saw that in B's talk at SUSY '06, & as an outsider it gave me some perspective. C. Townes (Berkeley Physics Nobel Laureate) uses the analogy of "uncovering stones". Picture physics as a landscape of stones, & a milestones are equivalent to uncovering stones.

  41. I forgot to put the link to the leopard picture, from Kruger NP/S. Africa A network of safari land-rovers communicated among themselves, to share information. We got a report of a leopard at dusk, & raced over there.

    About "elephant trampling". Mothers get agressive, if you get too close to their children. A well-known photographer got "stomped on" by a mother elephant, got a broken pelvis, & dang nearly died on the way to the hospital (far away)

    "Getting stomped on by an elephant is really inconvenient"

    In Chobe NP (Botswana), a mother elephant challenged us when we got a little bit too close.

    On the subject of male/female issues, the elephant society is maternal-based. There's a very strong social infrastructure, & females team up in the child upbringing.

    "The truth is that unpaid female labor is the priceless, invisible heart of the economy,"

    See here for a good article

    "My mother was the most beautiful woman I ever saw. All I am I owe to my mother. I attribute all my success in life to the moral, intellectual and physical education I received from her. "
    -- George Washington

    This whole male/female issue (in Science, also) is absurd. The female brings a different point-of-view ("left brained") , so of course it's of value: the "shotgun approach" to Science as per Linus Pauling.

    Q: How do get such good Ideas?
    A: I try a LOT of ideas
    [ quantity & from different points of view ]

    Is this world so freakin' backward (stereotypes), we're still nonsensing around? Get QUALIFIED people in the system, whether it be male or female. It's clear to me B (& other female scientists) have something to offer.

    I will say that the EOP (Equal Opportunity Program), giving credits based on being female or minority, is just as bad. It's Reverse Discrimination ("willful", conscientious Stupidity) which is worse than Discrimination ("unintentional", sincere Ignorance). Denying qualified white males the opportunity to contribute to Science, is equally tragic to denying qualified females.

  42. Hi Quasar,


    no, I meant, I haven't really figured out what to do with technorati. I guess, I sometimes misunderstand myself.

    Dear Rae Ann,

    thanks for the advice with the tea. The world looks so much better with a good night's sleep :-) I am not entirely sure I agree on Thinking is just like sex. At least for me, thinking is a rather lonely process. Regarding Lubos... he seems to be afraid of everybody who does not think how he does. And apparently he doesn't know much about women.

    Dear byen,

    thanks for the links. Look, I really find your travels very interesting, but I'd appreciate it if you could focus on Lee's book here.

    A nice weekend to all of you,


  43. Hi Shantanu,

    though I find the topic dark matter/energy very exiting, I won't have much time in the next months to write about it. You might want to look up Schombert's lecture, which is a very readable intro.

    Hi Christine,

    I also haven't yet received the copy. I am not even sure it was already sent out. In a certain way it seems to me that at least the EU waits for the US to sort out the matter, so they don't have to take any risk by judging on their own. I don't know about Brazil, is research strongly mainstreamed with the US?



  44. Uncle Al - Lumo, as usual, is not quite correct. In String Theory the equivalence principle is not a "derived fact" but an approximation who validity can be hoped for. See my post for quotes and links.

  45. Hi Bee,
    Your Technorati is working fine
    Interesting blogs on your tags too

    I see you've been debating Graviton 383 with JoAnne on line, are you not working at the same place?

  46. By online I mean publicly online
    at Cosmic Variance
    Do you not take summer hols, and chill in California beaches?

    Sometimes, sometimes, sometimes we've got it all and don't appreciate it. That line about bigfoot and waking up in a sweat had me roaring with laughter that is lol!

  47. Hi Quasar,

    I am about 400 miles South of JoAnne. That is, until next month. I am about to chill on a CA beach right now... on my way out the door... With a pile of papers in my bag... Wish I had time for a vacation. Would love to see Hawaii, but I am too busy stomping on Bigfoot's TOEs ;-)


  48. lol!

    Have a nice time
    Well give JoAnne my best regards when you speak to her or see her

  49. Hi Bee,

    Your review was based on a draft of the book, right? I have not received even a draft yet.

    In Brazil, research in physics and astrophysics has grown tremedously in the past 10 years or so. The quality of research is very good and getting better and better; some universities like Universidade de São Paulo (USP), Universidade Federal do Rio de Janeiro (UFRJ), and institutes like Centro Brasileiro de Pesquisas Físicas (CBPF), Instituto Nacional de Pesquisas Espaciais (INPE), for example, do offer excellent programs and graduate studies in the exact sciences. The research groups have collaborations in US and Europe.

    The problem is that there are too many good PhDs, there is no place to all of them, so they end up without a job in their specialization area. (That is what I meant by "double trouble in physics"). Most pos-docs end up as undergraduate/graduate teachers in universities of questionable level. I am glad that this is not my case, although I am not working in a Physics Department. (But in any case, I am writing a project that fuses concepts of real-time computational models and discrete space-times, so I hope to receive a grant on this project next year, if I am lucky enough. I'll write about this in my blog if I succeed).

    Our educational system "resembles" the European one (I'm referring to good schools here. Those at the fundamental and high school levels maintained by the government are disastrous. So if you can pay for the really good schools you will receive an education that is at the level of very good schools abroad).

    Brazil is a very, very rich country in natural resources: a very big and beautiful nation, full of paradisiacal beaches and florests, the bluest sky in the world, but also with large cities and industries. Brazil does not get involved in wars; christians, jews, muslims or whatever "live together in perfect harmony". :) There are no earthshakes or vulcanos or big natural disasters going on around here.

    There are only 3 problems in Brazil: corruption, poverty and violence. These are of course sad interlaced factors.

    Best wishes,

  50. My new book Quanum Motion also implies that string theory is incomplete, or even wrong. See my research website

  51. If we look back at Einstein when he was working on General Relativity, he had the physics: Michelsion-Morley, Equivalence Principle, but he had to find the math, which is where Grossman/Riemann came in.

    Today we have the math, an almost unimaginable pile of it, and we are trying to find the physics.

    The first is bijective, the latter may not be and thus leads us wildy astray.

  52. What nobody seems to realize is that String Theory is such a powerful science, that old notions like "experimental evidence" no longer apply. We've reached the golden age, and for those who desire to live in the past, those who desire a consistent relationship between theory and experiment, well, get out of our way. It's time for the true Enlightenment to begin.


    In "Beyond String Theory" in his book "The Trouble With Physics: The Rise of String Thory, the Fall of a Science, And What Comes Next" Lee Smolin asks:

    ". . . I believe there is something basic we are all missing, some wrong assumption we are all making. If this is so, then we need to isolate the wrong assumption and replace it with a new idea. What could this wrong assumption be?"

    The answer: :
    "...light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body."

    See also:
    "Shatter this postulate [of constancy of the speed of light], and modern physics becomes an elaborate farce!"
    Einstein: "If the speed of light is the least bit affected by the speed of the light source, then my whole theory of relativity and theory of gravity is false."
    Einstein: "I consider it quite possible that physics cannot be based on the field concept,i.e., on continuous structures. In that case, nothing remains of my entire castle in the air, gravitation theory included, [and of] the rest of modern physics."

    See also the discussion in

    Pentcho Valev

  54. Hi Pentcho,

    in later chapters you'll find mentioning of theories with varying speed of light. I don't think though that this is the point we are missing. Best,


  55. Hi Sabine,

    You may not be missing this particular point but nevertheless the speed of photons either depends or does not depend on the speed of the light source and the dilemma is FATAL for modern physics.



    Einstein's cult has spent billions of dollars for the destruction of human rationality and the success is remarkable. In 1960 Pound and Rebka measured the gravitational redshift: their result confirmed Einstein's formula c'=c+V/c, where c' is the VARIABLE speed of light in a gravitational field, c is the initial speed of light relative to the light source and V is the gravitational potential. By applying the equivalence principle one can easily deduce c'=c+v, where c' is the VARIABLE speed of light in the absence of a gravitational field and v is the relative speed of the light source and the observer. Clearly, the gravitational redshift is fatal for Einstein's theory and modern physics in general. Yet the destroyed human rationality has been misled into believing that the redshift is a glorious confirmation of Einstein's divinity.

    However happiness cannot be eternal and after 100 years of uncontrolled outrages Einstein's cult will have to disappear. Its last convulsion can be seen in

    where the gravitational redshift is shown to confirm, for the last time, the divine theory.

    Pentcho Valev

    "Genius Among Geniuses" by Thomas Levenson
    "And then, in June, Einstein completes special relativity, which adds a twist to the story: Einstein's March paper treated light as particles, but special relativity sees light as a continuous field of waves. Alice's Red Queen can accept many impossible things before breakfast, but it takes a supremely confident mind to do so. Einstein, age 26, sees light as wave and particle, picking the attribute he needs to confront each problem in turn. Now that's tough."

    The genius among geniuses at the end of his career:
    "I consider it quite possible that physics cannot be based on the field concept,i.e., on continuous structures. In that case, nothing remains of my entire castle in the air, gravitation theory included, [and of] the rest of modern physics."

    Pentcho Valev

  58. Pentcho said...
    By applying the equivalence principle one can easily deduce c'=c+v, where c' is the VARIABLE speed of light in the absence of a gravitational field and v is the relative speed of the light source and the observer. Clearly, the gravitational redshift is fatal for Einstein's theory and modern physics in general. Yet the destroyed human rationality has been misled into believing that the redshift is a glorious confirmation of Einstein's divinity.

    Dear Pentcho,

    This is a very basic misunderstanding about the constancy of light in General Relativity. True, the time of flight for photons can in GR change with the path travelled, as is e.g. measured at the Radar Echo Delay or such. This is a direct consequence of spacetime being curved, and is a confirmation of GR, not a mislead believing.

    Redshifted light changes it's frequency, not it's speed. Anyway, this is not a topic I want to have discussed here, and I would recommend you look up an introductionary textbook on GR instead. Best regards,



    Concerning the importance of his second postulate Einstein was quite clear:

    "If the speed of light is the least bit affected by the speed of the light source, then my whole theory of relativity and theory of gravity is false."

    It seems there can be no further ambiguity: shatter this postulate and Einstein's world becomes Newton's world again. Not if Newton's world has been converted into Einstein's ZOMBIE world - the vitality of this malformation is independent of Einstein's second postulate: p.35 ("Relativity without c")

    Pentcho Valev

  60. Pentcho, you are mixing up Special with General Relativity. In the standard version of general relativity the 'local' speed of light (defined through the lightcone) is constant. The global one isn't, because light rays can travel different ways whose lengths (and therefore the duration of the travel) depends on the background curvature, see my above link to the radar echo delay. This is *not* in conflict with general relativity, as also Einstein would also tell you if he still could.

    It is even possible to formulate theories with a 'truly' varying speed of light that preserve general covariance, see e.g. papers by Magueijo or Moffat, or better read Joao's book

    Faster Than the Speed of Light

    which gives a nice intro into usual GR before going wild. I can really recommend the book, it's not only a good intro into relativity and cosmology, it is also entertaining (should write a review at some point).

    You are making a very common mistake by using quotations of famous people out of context to claim things you didn't fully understand.



    SCIENCE VOL 307 "Special Relativity Reconsidered":

    "Now, however, some physicists wonder whether special relativity might be subtly - and perhaps beautifully - wrong."

    Einstein has clearly explained where the subtlety and the beauty come from:

    Einstein: "If the speed of light is the least bit affected by the speed of the light source, then my whole theory of relativity and theory of gravity is false."

    Einstein again: "I consider it quite possible that physics cannot be based on the field concept,i.e., on continuous structures. In that case, nothing remains of my entire castle in the air, gravitation theory included, [and of] the rest of modern physics."

    Pentcho Valev

  62. Pentcho,

    Unfortunately I have the impression you aren't even trying to listen to what I say. I am pretty damned close to deleting all your nonsensical comments, as they are plainly wrong, and I don't want my blog to contribute to distributing your erroneous believes.

    Would you please consider for one moment to think about what I say, or otherwise restrain yourself from commenting garbage, thanks,


  63. Bee wrote: "It is even possible to formulate theories with a 'truly' varying speed of light that preserve general covariance, see e.g. papers by Magueijo or Moffat, or better read Joao's book..."

    Haven't you noticed that Joao's definition of the variability of the speed of light (slower now than in the past) has nothing to do with Einstein's original definition of constancy (the speed of light is independent of the speed of the light source)? In fact, in 1911 Einstein showed that in a gravitational field the speed of light is VARIABLE:
    "So, it is absolutely true that the speed of light is _not_ constant in a gravitational field [which, by the equivalence principle, applies as well to accelerating (non-inertial) frames of reference]. If this were not so, there would be no bending of light by the gravitational field of stars. One can do a simple Huyghens reconstruction of a wave front, taking into account the different speed of advance of the wavefront at different distances from the star (variation of speed of light), to derive the deflection of the light by the star.
    Indeed, this is exactly how Einstein did the calculation in:
    "On the Influence of Gravitation on the Propagation of Light," Annalen der Physik, 35, 1911.
    which predated the full formal development of general relativity by about four years. This paper is widely available in English. You can find a copy beginning on page 99 of the Dover book "The Principle of Relativity." You will find in section 3 of that paper, Einstein's derivation of the (variable) speed of light in a gravitational potential, eqn (3). The result is,
    c' = c0 ( 1 + V / c2 )
    where V is the gravitational potential relative to the point where the speed of light c0 is measured."

    By applying the equivalence principle one could easily convert Einstein's formula into

    c' = c + v

    where c is the speed of photons relative to the light source and v is the relative speed of the light source and the observer in the absence of a gravitational field. Then one could remember Einstein's words:

    "If the speed of light is the least bit affected by the speed of the light source, then my whole theory of relativity and theory of gravity is false."

    Pentcho Valev

  64. Hi Pentcho,

    Einstein's Annalen der Physik papers on what is usually called his Prague theory of gravitation are available online at
    Über den Einfluß der Schwerkraft auf die Ausbreitung des Lichtes (Volume 35, 1911, pages 898-908),
    Lichtgeschwindigkeit und Statik des Gravitationsfeldes (Volume 38, 1912, pages 355-369),
    Zur Theorie des statischen Gravitationsfeldes (Volume 38, 1912, pages 443-458).

    But I really do not understand why you mention this theory here, unless you plan to deliberately create unnecessary confusion. I allways thought that the Prague theory is best understood exactly in the sense Bee has mentioned two posts earlier: that the speed of light appears variable in the proximity of a mass with respect to an asymptotic Minkowski frame. This is just the concept of coordinate velocity.

    So, this seemingly variable speed of light is an artifact of picking the asymptotic Minkowski frame as your frame of reference. I agree that this funny variability of speed of light is a confusing concept if you start learning about general relativity, taken that the foundation of this theory on the local constancy of the speed of light.

    But then, one has to take into account that this variable speed of light is a coordinate velocity, which needs not to be constant. Moreover, as you know, the Prage theory is not the full GRT yet - if I remember correctly, in essence because of the dependence of its formulation on the asymptotic Minkowski frame.

    But I had the impression that what you had in mind in the first place are ballistic, Ritz-like theories, where the speed of light depends explictely on the speed of the light emitting source. It seems that Einstein did think a lot about this possibility before zooming in on special relativity, see for example Einstein's Investigations of Galilean Covariant Electrodynamics prior to 1905, by John Norton, Arch. Hist. Exact Sci. 59 (2004) 45-105, or Ritz, Einstein, and the Emission Hypothesis by Al Martínez, Physics in Perspective 6 (April 2004) 4-28.

    As far as I know, there are lots of observations speaking against ballistic theories, from the original, astronomical de Sitter argument with double stars, over the discussions of Fox (Am. J. Phys. 30 (1962) 297, and Am. J. Phys. 33 (1965) 1) and the subsequent experiments, and so on...

    I have the impression that you think that the observational refutation of ballistic theories is in contradiction to the gravitational redshift. But in order to construct this contradiction, you have to deliberately mix up the coordinate velocity of light with the local, invvariant speed of light. Moreover, I would suggest you may not to cite Ekkehard Friebe or comparable experts if you want to be taken serious. Anyhow, I guess no further discussion makes any sense unless you have made clear which concepts you want to use.

    But then, this thread is definitely not the place to do this. I strongly suggest that we stop any further discussion of this topic at this point.

    Best regards, stefan

  65. Look, Pentcho, I strongly have the impression you have no idea what you are talking about. You are puzzling together quotations to argue instead of trying to understand differential geometry. Not to mention that all of that does not belong in this comment section.

    I will try it again: the speed of light in standard relativity is a constant, defined through the lightcone through a point. This is a local definition. The globally observed travel time for light rays can indeed depend on the path, as in the example from Einstein that you quote. This is not a contradiction to Einstein's theory.

    If you want to go with the interpretation of a 1911 paper, then you should at least ask yourself how c (c_0) is defined in this equation.



  66. Some of Smolin's concerns about freezing time was already dealt on my blog at

  67. Some of Lee's ideas about future theories are mentioned here:


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