## Wednesday, September 14, 2005

### Why no new Einstein II

In a public letter addressed to Peter Woit, Lee Smolin clarifies some issues and possible misunderstandings of his essay Why no new Einstein?

Lee's point was to emphasize that young ambitious theorists should be specifically supported to pursue their own research programs - independently of the "big" research directions. I have argued that the natural equilibrium - the invisible hand of the free market of ideas, if you wish - defines a very good balance between originality and reliability, and every bias such as Lee's proposal is bound to be counter-productive.

For example, the most likely reason why no young (or old, for that matter) person has convinced others about her alternative to string theory is that there probably exists no alternative to string theory.

If a field or subfield is overstudied, eventually the people realize that the amount of interesting problems in that field or subfield is rather small and there is too much overlap of their work with the work of others. If a field or subfield is understudied, it naturally attracts people because there are chances that significant progress can be done quite easily. The same comments apply to the situations in which too many people believe that something is true or something is false - as long as the community's goal is to search for the truth instead of finding evidence for some political goals outside of science.

If there is no progress or very little progress in a field, it usually means that no one knows how to make the next big step, and no amount of social engineering can change this basic fact because science can't be done by bureaucrats and politicians.

Lee says "String theory is criticized in the essay mainly because it is currently sociologically dominant". It's hard for me to understand this kind of thinking. I imagine a scientist as someone who judges the value of scientific claims and theories by their content, instead of their sociological dominance. Evolution is also dominant as a description of the origin of species which does not mean that I must immediately start to criticize it.

There are people who believe that there is a universal key to make progress in science and technology - to worship theories that have become sociologically dominant; this is the "scientific-consensus" type of people. Lee is apparently in the opposite, but not exactly competing group - according to which the progress is made by criticizing theories that are sociologically dominant.

I say that these opposite approaches are not really competing because their essence is more or less identical. The essence is to replace science by superficial sociological observations. The essence is to determine the answers to the big questions in advance. The essence is to decide how many talks should be positive and how many talks should be negative before the actual research is done. The essence is to guarantee a certain "share of the market of ideas" for a particular group - either the global warming alarmists or the loop quantum gravity proponents. I guess that both of these groups know that their importance will decrease if the scientific research is going to be done properly, so some of them try to emphasize non-scientific criteria.

Neither of these two "opposite" prescriptions can lead to any progress in the long term. Whether or not either of these two prescriptions "wins" a particular battle is a matter of chance. And the war is always lost because neither of these two approaches is a scientific approach.

Lee repeats some mysterious comments about "problems with string theory". As far as the detailed analyses of his statements by The Reference Frame can say, Lee's hypothetical "problems" don't exist. The last example of this sort was about Lee's conjecture that string theory may become inconsistent or divergent even at a finite order in perturbation theory. We've explained why we know that this conjecture is unjustifiable, and as far as we can say, demonstrably untrue. Lee's "sociological" justifications can't change the fact that what he says is not true.

They also can't change the fact that an even more rigorous proof of the perturbative finiteness of superstring theory is not one of the important topics in current theoretical physics simply because the question has been settled for quite some time. Everyone is free to investigate it; it's a very interesting piece of math. But no one has the power to force others to think that this is the golden problem of 2005.

Lee also mentions that the reason why Ted Jacobson spoke at a conference about loop quantum gravity is that that he became critical of loop quantum gravity. That's a pretty strange reason for a person to become a speaker at a scientific conference. At other scientific conferences, people usually speak because they have something interesting (and usually constructive) to say about the scientific questions that define the meeting themselves; not because they just become critical of something.

Ted Jacobson is a great guy who may be critical of loop quantum gravity - which means, of course, that he is correct in one particular "Yes/No" question - but he currently believes, among many other things, that black holes have a much higher entropy than the Bekenstein-Hawking entropy and that it's not a problem because this additional entropy is "hidden" below the horizon. Needless to say, this contradicts most of the detailed tests of black hole thermodynamics that have been done, especially the microscopic counting of the entropy in string theory.

Being critical of loop quantum gravity does not guarantee that the person has the right answers about other questions, beyond the single binary question "is LQG correct?". And the opinion about any question is only interesting for a scientific conference is there is some calculation, argument, observation, or experiment that supports it - not just because the sign of the answer fits an organizer's political agenda.

Lee even suggests that this bizarre policy to allow "critics" to speak just because they are critics should be adopted by other fields such as string theory. I could not disagree more. People speak at a conference about some topic because they study related questions - in a way that is sufficiently interesting and convincing for their peers - and because they have found some answers or evidence supporting particular answers, whether or not the evidence has a "positive" or "negative" flavor and whether or not they can be viewed as optimists or skeptics.

The speakers must know at least the basics of the field about which their speak, and they must be interested in some particular questions rather than dumb "Yes/No" screams about the whole field. These are the reasons why inviting a general critic - such as Peter Woit - could only be a funny idea to entertain the physicists once, but it certainly can't become a part of the standard organizational process because such steps would strikingly lower the scientific quality of conferences. One can't build a conference about string theory on speakers who have no idea what string theory is.

Incidentally, I don't think that there is not enough diversity of approaches in the string theory community. Sometimes the diversity - and the fragmentation of interest - seems just far too high. The fragmentation of interest is something that distinguishes the more quiet times from the revolutionary ones. Stanford, for example, seems to believe the anthropic principle that about 80% of the community rejects. There are places with a strong focus on topological string theory. There are places where string theorists interact with phenomenologists a lot. There are places where they interact with the loop quantum gravity proponents. There are places that prefer to study questions rooted in field theory and where they worship integrability. There are optimists as well as pessimists within the string theory community. I could continue for a long time. No one is currently able to convince others that everyone should study the same question. Someone may think that this is a great gift of diversity; but for most of us this is just a symptom of a lack of inspiration. Once new great ideas are revealed, diversity will be replaced by focus again.

Lee claims that he did not advocate funding of those who only work on foundations of quantum mechanics, but instead funding of those who are inclined to work on foundations of quantum mechanics. ;-) Big difference, is not it? Lee says that they are deep and independent thinkers. I would say this statement about a very few of them; there are many more crackpots who approach physics in this way. Most of the people who are bothered by the foundational issues in 2005 are those who have not understood the very basic framework of quantum mechanics and its inevitability. Most of them don't want to solve some cutting-edge open questions, but to "undo" even the discoveries made in the late 1920s. The people from the previous sentence are pretty different from those who solve actual problems connected with quantum computing.

Lee argues that the loop quantum gravity researchers don't ignore the well-known fact that infinite-dimensional constraint algebras generically acquire anomalies (a point emphasized to the LQG community by Nicolai et al., among others) and instead they have "rigorous existence and uniqueness theorems". Of course that Nicolai et al. are correct and Lee is wrong. (This is just one example where Lee views the established conclusions in string theory - such as the perturbative finiteness - as uncertain speculations while the statements in loop quantum gravity that are more or less safely known to be false - such as the off-shell closure of the constraint algebra - to be rigorous theorems.)

Nicolai et al. support their statement by a rather detailed analysis why the off-shell closure of the constraint algebra probably does not hold in the versions of loop quantum gravity that they have looked at. Lee only offers words; words that don't seem to be true.

Concerning Lee's comparison of the quantization approaches of string theory and of loop quantum gravity, he seems confused to me. The string-theoretical approach to quantization is not just string-theoretical. It's the correct, universal approach used throughout physics - in all field theories and in all descriptions of string theory that admit a classical limit. The approach of loop quantum gravity gives wrong results even for the harmonic oscillator. Lee says "give me a break, no one wants to quantize harmonic oscillator incorrectly". The reason why only a few want to quantize the harmonic oscillator incorrectly is that it would be very hard for them to convince anyone that it is the right thing to do. However, the loop quantum gravity community wants to apply the very same flawed techniques to quantize a much more complex theory - namely quantum gravity (or to quantize the worldsheet equally incorrectly).

Lee argues that the difference that can justify the application of the methods in gravity but not in the harmonic oscillator is probably that the harmonic oscillator is quadratic (Fock space?) while GR is not. Well, I assure Lee that one gets wrong results even for potentials that are as non-linear as general relativity. If a method fails in a very special and simple case, it is almost guaranteed to fail in a more general and complex case, too - because a more complex case requires one to be careful about many more subtleties (not less). The failure of the loop quantum gravity quantization of the harmonic oscillator shows that even the harmonic oscillator is too subtle for the techniques of loop quantum gravity to be any useful. And if the true essence of loop quantum gravity is in the techniques - which is what Lee always says - then the conclusion is that the failure of the techniques is enough to invalidate the theory.

Finally, I agree with Lee that it is much more likely that even a meaningful work about classical general relativity is written by a string theorist even though this community is fundamentally closer to particle physics, despite the overly self-confident claims of loop quantum gravity proponents that they have inherited the traditions of general relativity.

1. Lubos:

Your idea of free market place of ideas is a very good one. But I disagree with what are the driving factors behind a free market. The driving factor is not whether the idea is a good one or correct one. The driving force, like in any other free competitive systems, are fundings, group thinkings, formation of different establishment camps, all those things that has nothing to do with the correctness of an idea, but have everything to do with the surviveability of the ideas.

It's Darwinism at it's most fundamental principle: survival of the fittest.

If an idea is a good one or correct, it certainly helps its surviveability by helping it gain funding, acceptance and propagation. But that's only secondary influence. Especially when it is hard to show, or ultimately unclear, whether an idea is right or wrong, other more direct driving forces dorminate.

If you study any widely spread religious ideas, for example, you would find that virtually every successful religions have all the vital organism to help it survive and spread, including a mechanism to collect and expend money to help its spread. So how successful a religion can be, is not decided by how sounding or reasonable its ideas are, but on how efficient it collects money and spend them.

It's the same thing for either religions or politics, and even for scientific ideas. The science is slightly different because normally it has a widely accepted and agrred upon rules to judge correctness based on objective observations of nature. But when such judgements are not always possible, and especially when such rules are rejected and abundent altogether, science falls back to be just another religion.

That is what happened with global warming, big bang, super string, and other established crackpot theories. Another principle is in play here: the Copenicus

2. I'm a bit surprised by your invocation of a perfect "free market of ideas", where physicists have free choice of what they work on. This may be true for a tenured faculty member with solid funding, but it's not at all true in general. Grad students and young folks are beholden to the senior physicists who will determine their future prospects, and have their own ideas of what is worthwhile to work on. Even senior faculty need to convince the funding agency folks (who like buzzwords like "nano", "bio", and perhaps "string theory") every now and then.

This is not to say that Smolin's particular form of social engineering would be helpful, of course, or that something like the system we have is not somewhat necessary. It certainly says nothing about whether string theory is any good. But in our current system, it's not hard to imagine a field becoming overstudied.

3. Dear Jeff,

I agree that whole fields may become overstudied. But one can't be overcritical over particular fields. In other fields in science and especially outside of science, there are definitely many professions in which many more people work than necessary.

It's probably better to overstudy theoretical physics.

Sure that people must convince grant agencies, senior colleagues, and so forth. But I don't believe that grant agencies systematically prefer work that is not original. Neither of these things is a problem.

Theoretical physics is pure science, it has virtually no political bias, and getting new exciting ideas like Einstein is one of its first goals and everyone who is connected with the funding seems to realize that.

Most of us are eager about new Einsteins - but the new Einsteins must do it right like the old one in 1905-1916.

Best
Lubos

4. On the other hand, if String Theory happened not to be the Theory of the World... should you accept as a corolary the falsehood of the Free Market hypothesis?

5. The new Einstein must be able to explain the old Einstein postulates, like I did...

http://forum.physorg.com/index.php?act=Search&CODE=getalluser&mid=4478

6. This comment has been removed by a blog administrator.

7. Dear Lumo,

You write that perhaps the reason why nobody has been able to convince string theorists of an alternative to string theory, is probably because there is no such thing.

I've just read Dr Randall's "Warped Passages", and she credits you with proof reading.

What struck me were her statements about half way through that since the strings are so small, accelerator energies achievable today are 16 orders of magnitude too low to test strings.

In the concluding chapter, she gives a sample of the wide range of stringy ideas. The justification for 10-D string theory being equivalent to 11-D supergravity (Witten's 1995 work), giving rise to M-theory, is fine. I'm not worried about the 4-D spacetime being either a brane on 5-D spacetime, or the 4-D spacetime being a hologram of a 5-D spacetime. These mathematical equivalences are undoubtedly interesting to mathematicians, but the physics is simply not there yet.

Dr Randall, despite admitting that ST energies are 16 orders of magnitude too high for direct tests, suggests indirect tests. These include energy balances. We all know that with so much 'dark matter' or 'dark energy' postulated by the mainstream model of the big bang (general relativity force-fitted to observation) the energy balances are not going to come from standard cosmology.

Therefore, ST is a dead end. What would be nice is would be a review of the way in which general relativity models the big bang: starting from the observations. When you do this you see that the Hubble law in spacetime is not proclaiming the increasing velocity of galaxies away from us with distance, but with time past.

Thus, the big bang can better be formulated from observations as an acceleration of matter outward in spacetime. The acceleration is equal to light velocity divided by age of the universe a = dv/dt = c/t = cH (because Hubble constant is H = 1/t, ignoring the correction factor or 2/3 or whatever applied for the slowing down of the expansion by gravity when gravity is assumed to be independent of the big bang).

This acceleration allows us to calculate the outward effective force of the big bang by Newton's 2nd law F=ma. The 3rd law tells us that there is an equal inward force. This physically occurs because the spacetime fabric, such as higgs field, fills the 3-D volume around fundamental particles, and flows in to fill the voids left behind the particles as they rush outward.

Thus we get an inward pressure from the spacetime fabric which gives rise to the force of gravity, since the pressure is shielded by large quantities of matter: http://nigelcook0.tripod.com/

Weirdly, people try to use special relativity to discredit the spacetime fabric by claiming that "all" motion is relative, when in fact acceleration is not relative but absolute (hence the very reason why Einstein invented GR).

One severe problem with 'special relativity' is that it is presented as the last word, as a disproof of reality. For example, in this big bang universe we are at an age of 15 Gyr, and everything we see is younger. The farther the star or supernova we see, the further back in the past it is, because of the time taken for the light to get here. So if we see two simultaneous supernovae, we can work out absolutely which happened first by knowing their distances! This is the exact opposite of the popular writings on 'special relativity' which say that you cannot tell which star exploded first.

Another issue is absolute motion; the 2.734 K cosmic background radiation is 3 mK blue shifted in the direction of our absolute motion and 3 mK red-shifted in the other direction.

So we can tell our absolute motion from that (about 400 km/s, partly due to the attraction of the Milky Way towards a big galaxy nearby, but if for sake of argument we have been going 400 km/s since the big bang - which is an order of magnitude approximation - we are only 0.3% of the radius of the universe, in other words within 0.3% to the middle of the big bang).

This effect was called 'the new aether drift' (the title of a Scientific American article on the subject in the late 1970s). Critics responded by fiddling Copernicus' discovery. They claimed that Copernicus did not discover or work on the solar system, but instead had discovered that 'the earth is not in a special place in the universe'.

Best wishes,
Nigel

8. Dear Nigel,

your text is more or less OK until you write the following sentences:

"We all know that with so much 'dark matter' or 'dark energy' postulated by the mainstream model of the big bang (general relativity force-fitted to observation) the energy balances are not going to come from standard cosmology.Therefore, ST is a dead end."

I am completely lost in your reasoning and strongly believe that it is not my fault. ;-)

The existence of dark matter and dark energy is a very probable fact that follows from the experimental data combined with general relativity. General relativity is the correct classical theory of gravity. Most likely it is also correct for calculation of the dark energy and dark matter dynamics. Every quantum theory must agree with general relativity at these scales.

String theory does, and its vacua also offer natural new elementary particles that play the role of the majority of dark matter. At any rate, deducing that string theory is a "dead end" from your confused considerations of classical cosmology shows that your brain had to make a horrible mistake, and I encourage you to think about it again because what you produced makes absolutely no sense.

OK, when I continued to look at your text, I also noticed that you want to disprove special relativity. Hopefully you will find a better party to discuss your great ideas.

Good luck
Lubos

9. Dear Lumos,

Mathematically special relativity is correct, so neither I nor anyone else can disprove it.

It is actually a crucial advance, but is misrepresented in a lot of physics courses as disproving the existence of a spacetime fabric, which clearly it does not do.

Einstein made it clear in his Leyden University lecture of 1920 that space without a spacetime fabric is unthinkable.

Another falsity of the popular presentation of special relativity is that it disproves the existence of all absolute motion, when in fact it only deals with non-accelerating motion. Acceleration induces forces which are absolute, if you have a force then there is acceleration. This is not subject to the relativity implicit in Maxwell's equations.

General relativity is correct as far as it goes, but it takes Newtonian gravity as the weak field approximation. If there is a mechanism for gravity, that affects the constant G in the Newtonian theory and thus in general relativity. The test for this is whether the most distant galaxies, receding at nearly light speed, are being slowed down or not by gravity pulling them from within the universe.

Since Perlmutter's results in 1998 for supernovae (using completely automated detection with CCD telescopes) disproved the prediction from general relativity, we know something is wrong.

The official solution is that general relativity as it stands (pulling gravity) is right, and something is speeding up the galaxies to overcome gravity.

The reality is that gravity is the shielding of an inward pressure of the spacetime fabric, generated by the mass moving outward. There is therefore no gravitational pull slowing down distant galaxies.

Best wishes,
Nigel

10. Dear Lumos,

Re: your comment "your confused considerations of classical cosmology shows that your brain had to make a horrible mistake, and I encourage you to think about it again because what you produced makes absolutely no sense."

When I say ST is at a dead end I'm referring to the approach by which you hope to get something useful out of an energy balance using the existing cosmology.

With 90% of the mass of the universe undetected if classical cosmology is right, plus the issue that distant expansion is not being slowed down as classical cosmology predicted, it looks like a dead end.

My "great idea" comes from LeSage, who suggested gravity is a pushing effect in 1748 and used it to predict the nuclear atom (because the force would have to penetrate atoms to act on every particle of matter, not just on the outer surface area of a planet): George Louis LeSage, Lucrece Newtonien, Nouveaux Memoires De L’Academie Royal de Sciences et Belle Letters, 1782, pp. 404-31. It is online at http://www3.bbaw.de/bibliothek/digital/struktur/03-nouv/1782/jpg-0600/00000495.htm

In CERN preprint EXT-2004-007 and in two Electronics World articles I showed that Feynman's ideas on presenting general relativity as a compressing force of the spacetime fabric were equivalent to the Lorentz contraction: the spacetime fabric pressure when moving shortens objects in the direction of motion, and the contraction term in general relativity supplies the same effect for gravity.

‘… the source of the gravitational field can be taken to be a perfect fluid…. A fluid is a continuum that ‘flows’... A perfect fluid is defined as one in which all antislipping forces are zero, and the only force between neighboring fluid elements is pressure.’ – Bernard Schutz, ‘General Relativity’, Cambridge University Press, 1986, pp. 89-90.

‘It was proposed that a mechanism of gravity should be developed to rigorously test all of the consequences of the physical fluid model for the fabric of space… The success of this model for gravity has implications for the unification of fundamental forces via quantum theory.’ – Nigel Cook, ‘Solution to a Problem with General Relativity’, CERN Document Server paper preprint EXT-2004-007.

The paper is at http://nigelcook0.tripod.com/ and shows that for the correct mechanism of gravity due to LeSage, the critical density is exactly .5e^3 (or about 10 times) higher than the true density. Hence most of the dark matter is eliminated, enabling an energy balance to become feasible.

It is interesting that your reaction is so similar to Peter Woit's and also Quantoken's, who both dismissed it as 'nonsense'.

When I pointed out that the editor of PRL, Stanley Brown, used ST to block my paper, Peter wrote http://www.math.columbia.edu/~woit/mt/mt-comments.cgi?entry_id=215 :

I'm tempted to delete the previous comment, but am leaving it since I think that, if accurate, it is interesting to see that the editor of PRL is resorting to an indefensible argument in dealing with nonsense submitted to him (although the "..." may hide a more defensible argument). Please discuss this with the author of this comment on his weblog, not here. I'll be deleting any further comments about this.

Posted by Peter Woit at July 7, 2005 07:27 PM

Both you and Peter need to see this: ‘(1). The idea is nonsense. (2). Somebody thought of it before you did. (3). We believed it all the time.’ - Professor R.A. Lyttleton's summary of inexcusable censorship (quoted by Sir Fred Hoyle in ‘Home is Where the Wind Blows’ Oxford University Press, 1997, p154).

Best wishes,
Nigel