Mix city council candidates and bloggers and what do you get?

One of the causes of global warming.

Blogging live from Kaveh Kanes in downtown H-Town, where brunch and free Wi-Fi are being served. A semi-full report later, but I'll put it over here.

Update: Discussion and comments from nine candidates and seven bloggers is here.

Texans for Hackett is rolling

42 people have clicked on the links furnished by Greg (who hatched the idea) and participating Texas bloggers and have contributed almost $1,200, with an average donation of $28.45 . Richard Morrison fired up his listserv and collected a fourth of that total.

That's as of this morning.

An absolutely amazing example of the power of the netroots. Let's take it all the way to the finish line next Tuesday.

NOW I'm a believer

When they can beat Pedro Martinez on the strength of the mighty bats of Brad Ausmus and Adam Everett, then I think the Astros might have sump'm goin' on.

20-6 in the month of July (and three of those L's came at the hands of the division-leading St. Louis Cardinals fresh off the All-Star break).

Saturday night we'll go club-leveling to see Andy Pettitte square off against Tom Glavine. One of my guests is a big Mets fan. She has reminded me twice since I acquired tickets to this game about 1986.

I might not even boo Beltran too badly if the score is not close in the late innings.

"Fight 'em 'til Hell freezes over, and then fight 'em on the ice": Paul Hackett and David Van Os

One of my fellow H-Town bloggers started an online firestorm earlier this week when he suggested that there was no race in the state, or the nation for that matter, that Democrats should let go uncontested. As proof of committing this strategy to action, I give you the following:

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Paul Hackett is a Democrat, Marine, and Iraq War veteran running for Ohio's 2nd congressional district seat (vacated by newly appointed trade representative Rob Portman, who helped DeLay and Cheney twist enough arms to put CAFTA over the top last night), against Republican Jean Schmidt in next Tuesday's special election.

Hackett thinks Bush is a chickenhawk.

Schmidt has raised and spent hundreds of thousands of dollars, Bush is making recorded phone calls into the district on her behalf, she is flying on private jets to DC to raise more money, and all of the rest of the typical full-court press is being applied by the GOP to hold on to a district that has gone at least 70% Republican for the last twenty years (28% for the Democrats in 2004).

Why? Because despite all that, polls show Hackett within the margin of error.

Oh yeah, the Republicans are also attempting to Swift-Boat him.

Join me, and these other Texas bloggers, one of whom has appointed Hackett an Honorary Texan, by doing what you can to support his candidacy in these few days before the special election next week.

===============

David Van Os, a former general counsel of the Texas AFL-CIO, is the Democratic candidate for Texas Attorney General. He received the President’s Citation for Achievement in Civil Rights from the NAACP in 1990, and he went to Florida in 2000 to assist the Democratic Party in that state's infamous vote recount efforts. In private practice as a labor law attorney since 1984, Van Os also advised retired Lt. Col. Bill Burkett, he of the CBS-Dan Rather/Dubya-TANG memo fame, during that affair.

This past week, Van Os named prominent civil rights activist Rev. Peter Johnson his campaign manager and traveled to Cass County, Texas, where a hearing was held by the NAACP and the Southern Christian Leadership Conference regarding the circumstances of the assault of Billy Ray Johnson, a mildly retarded African-American man who was beaten badly by four white men and left for dead atop a fire ant mound. The FBI and local law enforcement officials investigated the case and came to the conclusion that what happened to Johnson was a crime based on his mental incapacity, not his race; thus no state or federal hate crimes or civil rights charges were lodged. The men charged and tried -- one of whom was working as a guard for the Cass county jail at the time -- received deferred adjudication, probation, and brief jail sentences of 30 to 60 days. (Two other recent deaths of African-Americans, one from hanging and one from a rifle blast, were ruled suicides by local authorities under suspicious circumstances. Chillingly, empty nooses have been found hanging from tree branches in apparent warnings. These reports have enjoyed a low profile in local media; it took a story in the Chicago Tribune to elevate the Johnson case to semi-public attention.)

In 1998 Van Os ran for the Texas Supreme Court against then-Justice (now incumbent Attorney General) Greg Abbott and was defeated. In 2004 he ran again for the Texas Supreme Court against now-chief justice Scott Brister and lost 58% to 41% (Bush defeated John Kerry in Texas by a count of 60-38).

In short, Van Os knows first-hand about David vs. Goliath matchups. He has won a few battles and lost a few, but he has always fought on the side of the little guy against the big-moneyed corporate and special interests, the ones who currently hold the Texas Supreme Court and the Legislature in a hammerlock. He is a progressive populist in the grand tradition of Texas liberals like Ralph Yarbrough and Oscar Mauzy. Here's a sample from one of his recent speeches:

It is time to discard the "avoid polarization at all costs" strategy, the "take no risks" strategy, the "appeal to everybody" strategy, and the "chase the middle" strategy. It is time to remember what Jim Hightower told us 20 years ago: "there's nothin' in the middle of the road but yellow stripes and dead armadillos." It is time to cease the followership strategies of scripting campaigns on the basis of what pollsters say people thought yesterday, and assert the leadership strategies of campaigning for what we know to be right based on our deepest convictions of what we want for tomorrow. It is time to stop worrying about whom we might offend if we speak truth to power, and start worrying about what value are our lives if we don't speak truth to power. It is time to cherish partisan Democrats and reject nonpartisan Nothingcrats. It is time to forget "right-left" analysis and install "right-wrong" analysis. It is time to replace the "liberal-conservative" spectrum with the "liberty-tyranny" spectrum. It is time to stop worrying about how to get money from big donors and start worrying about how to get more money into working people's paychecks. It is time to fight for better lives for voters instead of peddling promises to voters. It is time to treat public office as a duty, not a promotion. We must fight for the people, not in order to win their votes, but in order to win them justice.

Van Os considers it a successful fundraiser when a group of forty club Democrats in Houston pass the hat and get enough to pay his traveling expenses from San Antonio.

Do what you can for him.

(In the interests of full disclosure, I will be serving on the steering committee of Van Os' campaign.)

Chris Bell is in

In an e-mail delivered just now to my inbox (emphasis mine):

Over the past half year, I have traveled all over Texas, literally exploring the race for governor. You have indulged me in this process as I sought the answers to some important questions, some personal (and Alison's doing better every day, thanks) and some of them public: Can a Texas Democrat win? Are Texas Democrats ready to try something different? Do people see what is happening in Texas the same way that I do?

Well, I have my answers, and today I am proud to share the news that I've decided to run for governor.

If you ever want people to question your sanity, explore running for statewide office as a Democrat in Texas. When this started, I had no clue as to how people might respond. I have not been that nervous about getting on the phone since running for Houston City Council the first time. Everyone agreed that it would be a tough road for any Democrat but, interestingly, the overwhelming majority of people with whom I spoke could also see that Rick Perry is creating a huge opportunity for a Democrat. They also agreed it wasn't enough for me to be right about Rick Perry being wrong; it would take a positive message that could unite all Texans.

As I've traveled the state, I've been talking about the "New Mainstream," the disaffected majority of Texans who know that Rick Perry couldn't lead a silent prayer. I've been talking about how budgets are moral documents that have both a fiscal impact as well as a human cost. And, as a public school parent, I've learned that parents and teachers across Texas share my frustrations with Enron-style accountability that encourages dropouts and systematic fraud by teaching our kids nothing as much as how to take yet another standardized test.

The best part of the exploration phase has been watching as people came out of their seats to cheer. Some memories have really stuck with me: the young college student who approached me in Brazos County, with tears in her eyes, telling me how inspired she was by what I had said; the pastor in Mount Pleasant who told me he would be with me all the way; the County Chair in Lubbock starting the chant, "Run Chris, run!" I won't pretend that people were responding to me so much as to hearing someone talk about the world the way it is, and not just the way it polls.

The one remaining question was whether my wife, Alison, would be up for the fight. I am happy to tell you that the prognosis after chemotherapy is as good as it can get. Ali has been my rock ever since we've been together, and there's no way I would embark on something as challenging as a race for governor without her feeling up to it. As everyone knows, she's every bit the fighter I am, and she feels strong enough to join me in this battle.

We're launching our campaign for governor on Sunday afternoon, August 14th, at 2PM in Austin, and Alison and I want you to join us there. If you would like to help organize participants from your city, please let us know. For more
information about the launch rally, visit our website:

http://www.chrisbell.com/launch

We are going in with eyes wide open, aware not only of the odds but also of the possibilities to achieve great things for Texas. I look forward to seeing you in Austin and thank you from the bottom of my heart for your friendship and support.

Sincerely, Chris Bell
http://www.chrisbell.com/

P.S. Ironically, as I was writing this letter, I received a "thought for today" e-mail from a friend. It was a quote from Anatole France that says, "To accomplish great things, we must not only act, but also dream; not only plan, but also believe." I couldn't have said it better myself. I dream of a better state and believe we can build it together.

Background independence

Lee Smolin has submitted "The case for background independence", hep-th/0507235. Background independence is definitely an interesting topic in philosophy of physics. Some of Lee's points can be agreed with, for example:

• It is desirable to find a background independent formulation of string/M-theory
• Such a formulation would likely to answer the questions whether the landscape approach to string/M-theory is correct; why it's not; what it should be replaced with.

These are the anthropic topics and it has been described many times why I agree with Smolin and others. However, I can't agree with the other points about background independence, especially Lee's opinions that

• We should try to revive Leibniz's relationism or Mach's principle
• Philosophical reasoning about background independence is relevant for derivation of physics of a particular background
• It's better if your theory contains no space (possibly not even an emergent one) rather than if it does
• Quantum mechanics should be replaced by something else that goes "beyond it"

and many others that will be discussed in this text.

See also: Background independence in AdS spaces

OK, let me start with the questions about relationism and Mach's principle. I highly recommend you the second popular book by Brian Greene, "The Fabric of the Cosmos", where the relative vs. absolute debate is covered in the first chapters. And the presentation is very nice.

What do I think about these issues? Unlike others, I have never been impressed by the relationist ideas and Mach's principle.

Leibniz's principles




It's easy to agree with Leibniz's "principle of sufficient reason": one must rationally justify every choice made in the description of Nature. However, this principle must be interpreted properly (justification: a proper interpretation is always a better choice than a wrong interpretation). A proper interpretation always allows you to make a choice because this choice leads to an agreement with this interesting world. More concretely, the coordinates and similar things are useful concepts to describe reality despite some redundancies and symmetries, as we will argue below. The success of Newton's theories is undoubtedly a sufficient reason to justify every single piece of his theory.

On the other hand, Leibniz's "identity of the indiscernible" - which says that the objects with the same properties must be identified - is technically wrong in all theories we've been using in the last 300 years. If two objects/states A,B are related by a global symmetry transformation, they have the same properties but they must still be considered as two distinct objects (configurations or states in the Hilbert space) - two objects that are not equal (=) - otherwise the mathematics would break down. Leibniz's approach to the "identity question" may be attractive philosophically, but in my opinion, it is more important that it is technically untrue in all successful theories of reality and we reasonably expect that it will remain untrue in the future theories, too. The only allowed interpretation is that Leibniz has defined another relation (equivalence) that is different from the usual mathematical identity.

Obviously, not all physicists share my viewpoint that the verifiable truth is more important than the philosophical prejudices; in other words, the philosophical prejudices may be incorrect even if their defenders sell them as deep ideas (and these chaps sell themselves as smart scientists and philosophers). But let us return to the question "Does space objectively exist?". There are aspects of "relationism" that are part of the standard physics cannon; and aspects that are an unnecessary philosophical addition that usually brings us on a wrong track.

In classical physics, the Galilean symmetry and the principle of relativity is alright. It's a well-known fact that you can't determine whether your train is moving or not. This fact is reflected by a mathematical property of the equations of motion: they only involve the acceleration and the differences between positions of objects; they don't directly depend on velocities. (Such a dependence may appear when you consider friction; friction typically picks a priviliged reference frame such as the frame associated with water in the ocean.)

Special relativity - an ideal amount of a deformation

In special relativity, the Galilean symmetry is deformed into the Lorentz symmetry which is in a sense deeper, as argued in the article about the depth. The Lorentz symmetry respects the same "beauty" as the Galilean symmetry (the beauty means, in this case, the equivalence of inertial observers) but it is more general because a parameter - equivalent to the speed of light - has a more generic, finite value. The Lorentz symmetry is a strong constraint on the possible form of the physical law. And every principle that has a chance to be true (or at least deep) and that has the capacity to constrain the equations of physics is welcome. The finiteness of the speed of light links mass and energy by Einstein's most famous formula and it reduces the number of independent physical fundamental concepts in many other cases, too.

The Galilean spacetime implied that the space and time were independent quantities (much like the energy and mass, and others). The Lorentz deformation is an ideal one (a golden compromise): it essentially identifies space and time (and mass and energy) with a power of the speed of light as the conversion factor. However, any choice of the speed of light leads to a physically equivalent theory (with a different choice of units). Had we made a larger deformation, there would be new undetermined dimensionless parameters. Special relativity shows the "optimum of beauty". Quantum mechanics is doing something similar and identifies time with energy (with hbar being the conversion factor), again without introducing new dimensionless parameters. Quantum gravity ideally sets another constant (Newton's constant or an equivalent) equal to one which allows to calculate all dimensionless numbers.

Coordinates: synthetic vs. analytical geometry

Also, as a kid, I was very impressed by coordinates and the possibility to analyze geometrical questions analytically, by looking at the equations involving coordinates. I don't know whether some of you have had the same feelings, but the mathematical tasks to solve a geometrical problem by "synthetic geometry" without the coordinates always looked like a useless childish exercise to me (which does not mean that one can't get good at it); it was recreational mathematics for children. If you can find the truth by using the coordinates, why shouldn't you use them? Coordinates are great and they are, to some extent, real. They are real modulo translations, rotations, and the Galilean (or Lorentzian) boosts. But there are only 10 parameters for this Poincare group in the whole Universe while the coordinates of the objects you want to study may be counted in thousands. No doubt, most of them are physical. We can't live without them or something more or less equivalent. The Cartesian coordinates, for example, look more fundamental than the angle between a bucket, Mercury, and a Mercedes, so why shouldn't we use them?

The relationist approach seemed to be an attempt to fight against the concept of coordinates; an attempt to pretend that they don't exist or they are unphysical; an attempt that must fail unless the coordinates are replaced by some assumptions that are equally powerful and essentially equivalent (but perhaps more awkward than the coordinates) because the space simply exists, to some extent, and you can't hide it. Also, the relationist approach did not look like a mathematical constraint on the possible form of physical laws. Instead, it was a way to make the questions quantitatively ill-defined. The relationist principles never looked like well-defined symmetries of a physical system; they were a method to show that no choice of the degrees of freedom is good enough for a sufficiently dogmatic person. We may summarize the situation: there was nothing that I would naturally like about the relationist approach.

Don't get me wrong: self-contained "bootstrap" systems that look non-quantitative and uncalculable at the beginning may be fine and very deep in physics but only if they're temporarily uncalculable. Relationism seemed to be a direction that wanted to make things permanently uncalculable.

Mach's principle

This description also holds for Mach's principle. According to Mach, the reason why you feel the centrifugal force when you rotate are the distant stars in the Universe; your rotation may be defined with respect to these static stars. If you remove all the stars, you can't distinguish a rotating yourself from yourself at rest and the centrifugal force disappears. While this idea was presented as a profound one by many popular books, it has always seemed obvious to me that it was a philosopher's nonsense. There can't exist any natural way to transform this paradigm into a set of mathematical objects and equations. The very goal of this approach is to show that everything about the coordinates is always unphysical. We simply know that it's not true: ideal solid bodies follow the rules of the Euclidean geometry (in a good approximation) and all the coordinates in this geometry are meaningful modulo a few symmetries we know. When we add dynamics, it's only the Galilean or Lorentz symmetry that must be subtracted from the reality of the coordinates. The fraction of the unphysical coordinates becomes arbitrarily small as we study ever more complex systems; and I just don't see anything wrong about auxilliary variables in physics.

Also, the Machian approach seemed as one of the confusions about the units. If the number of stars in the Universe were smaller, Mach's disciples argue, the inertial force would be smaller by the same factor. But in which units? It seemed clear that one can always use units in which the inertial force is independent on the number of stars. The exception is the case in which the number of stars is zero, but that's a singular case that can't agree with our Cosmos, and that could already be enough to make it uninteresting for a physicist.

Another technical problem with Mach's principle was the following.

Imagine that there are only two stars in the Universe. One is above you and one is below you. You will be able to distinguish rotational motion - except for the motion around the axis connecting the two stars. Does it mean that the magnitude of the centrifugal force should depend on the direction? Such a dependence would break the rotational symmetry of some laws of mechanics. Such a breaking does not seem to occur in reality. Moreover, it is ugly. Also, the argument seems to depend discontinuously on the size of the stars because if the stars have nonzero size (or if they have planets), you should be able to distinguish rotating objects once again. Let me summarize: Mach's principle always looked cheap, ill-defined, and nonsensical to me.

Mach's principle in GR

Einstein was strongly impressed by Mach's principle. It was one of the motivations why Einstein was developing General Relativity. And the resulting theory predicts some phenomena - such as frame dragging - that smell of the Machian flavor if you look at it from the right (or, equivalently, wrong) way.

But eventually, General Relativity had killed Mach's principle.

Mach's principle has not only been challenged: it became one of the weird prejudices that often leads you to wrong conclusions. Mach's principle was the main reason why so many people in the 1960s thought that the gravitational waves could not exist in GR; they thought that all such solutions always had to be pure gauge which means that they could be transformed into flat space by a coordinate transformation.

Of course, it's not true. If you analyze the equations in the linearized approximation and if you describe the diffeomorphism invariance using the same language as other gauge invariances - in other words, if you apply the rational and reliable tools of field theory - you will get the right counting of the physical polarizations in a few minutes.

A Nobel prize has been given in the 1990s for indirect experimental evidence of the existence of gravitational waves (a binary quasar is losing energy as it emits the gravitational waves). And I don't think it was an erroneous prize. LIGO, VIRGO, and LISA can tell us much more than just the answer to the simple question about their existence. Gravitational waves simply exist; they are a prediction of GR that is as much justified by the very basic principles of GR as any other phenomenon (such as the Mercury's perihelion precession, bending of light, or gravitational red shift). The existence of gravitational waves implies that there is something in the empty space that can oscillate; the "fabric of the cosmos" does exist, indeed. Any theory that wants to reproduce the successes of GR must agree with the existence of gravitational waves. In the low energy limit, they must be described by the same mathematical expressions. Moreover, in a quantum theory, gravitational waves must be coherent states of quanta called "gravitons" that are analogous to photons, quanta of the electromagnetic field.

An attempt to revive Mach's principle means to argue that the gravitational waves do not exist. It is a struggle to return us not only before General Relativity; it is a program to return the humankind to the pre-Newtonian era and the dark Middle Ages. Some people may be permanently impressed by Mach's principle and some people may find it shallow after a closer scrutiny. These two groups may be composed of equally nice people. But the difference is that the critics of Mach's principle have a good physical intuition; its advocates are philosophers who are unable to think analytically and quantitatively and they prefer to insist on prejudices that can be shown flawed by a five-minute-long quantitative argument.

Objects vs. relations

There is a lot of other philosophical waste around these questions that does not impress me much. On page 9, Lee starts with his theses. R1 says that "There is no background". We have discussed this one already. Using my language, R2 says that "The degrees of freedom should always be described as relations between the objects, not the objects themselves". I view it as a silly philosophical prejudice. There are great theories where at least some of the degrees of freedom are associated with the objects themselves, not just their relations. These are equally good degrees of freedom; the statement that relational degrees of freedom are "better" is unjustified (it violates a principle of Leibniz above, for example) and most likely incorrect, too. Also, you may view a property of the object A as a quantity describing the relation A-G between her and God, or whatever. There is no real difference.

Moreover, when there are some symmetries, the degrees of freedom assigned to the objects themselves may behave much like the degrees of freedom connected with their relations. R3 says that the degrees of freedom (the "relationships" in this case) evolve with time and the role of time is to order them; well, that's what time usually does except that Lee seems to mod out by the time reparameterization symmetry from the very beginning which I find awkward especially because a good absolute measure of time - including the reparameterization (not just ordering) may be measured by gadgets known as "clocks".

Let us agree that if background independence means to return us to the Machian dogmas that the space (and gravitational waves) can't exist, then it's a medieval silliness that we should no longer discuss in the 21th century. The assertion that "the relationist approach is powerful" is ridiculous simply because there does not exist a single relational theory that would describe anything in the real world, at least approximately. The field-theoretical revolution at the end of the 19th century has led us to exactly the opposite way of thinking: even in empty space, there can be fields whose existence is as real as the existence of material objects. They just describe other, field-theoretical degrees of freedom. The gravitational field is one of these fields that is connected with geometry of spacetime and with gravity; it exists much like the electromagnetic and other fields. Quantum field theory has shown that the positions of objects are not only on par with the values of fields in empty space; in fact, the former (particles) emerge from the latter (fields) once you quantize the fields.

Atoms of space

Another weird attempt is to say that the gravitational field only reflects long-distance properties of a complex system of "atoms of space" that can be found in very many different configurations. Well, such an opinion is nothing else than the gravitational counterpart of the luminiferous aether behind electromagnetism, i.e. the gravitational aether. It does not really matter whether one uses new terms such as "spin network", "spin foam", "background independence": these things mean nothing else than new versions of the gravitational aether and they are as discredited as luminiferous aether. If the "atoms of space" had many possible non-equivalent states in which they could be found - but all of these states would look like empty space - then the empty space would carry a (large) nonzero entropy density. Such entropy density is a four-vector whose nonzero value (probably the huge Planckian density!) would massively break Lorentz invariance of the vacuum.

It's clear that no such massive breaking is allowed in a realistic theory - not even a semi-realistic theory. In other words, the Minkowski vacuum must be locally unique. The requirement of the Lorentz invariance - even an approximate, local one - hugely constrains possible types of "compositeness" of space, and it definitely rules out all "chaotic models" of the vacuum. It is incredible that one may obtain something that looks like the empty space (or a gravitational wave) by making a condensate of seemingly complicated objects such as the closed strings with the graviton excitation. Nevertheless, we may show that these closed strings behave just like the metric. (At stronger coupling, the graviton is not composed "purely" of closed strings because they are not the only fundamental objects. For example, at very strong coupling in type IIB, the graviton is almost entirely composed of a D1-brane.) In virtually all other cases, we may show that the presence of some objects in space simply destroys the ability of the space to act as locally Lorentz-symmetric, empty space.

Comparison of aethers

Incidentally, the luminiferous aether in the 19th century was much more developed than the current versions of the gravitational aether. Maxwell has designed several models and FitzGerald has even produced a working model of aether based on wheels and gears. Be sure that it is not easy to create a system where only transverse waves propagate but Maxwell and FitzGerald were able to do it and immitate Maxwell's equation. (No model of gravitational aether that would mimic Einstein's equations has been constructed as of 2005.)

Although the 19th century luminiferous aether was much ahead of the current proposals for gravitational aether, it was exactly luminiferous aether whose complete destruction and humiliation became one of the most important symbols of the Einsteinian revolution in physics. Einstein updated and clarified Lorentz's observations that only one electric and one magnetic vector exist in the vacuum and they are not made out of anything more fundamental; he found a symmetry - namely the Lorentz symmetry - relating the electric and magnetic phenomena and showed that this valuable, precious symmetry would be broken by any system of wheels or anything else that you imagine to occupy the empty space. Wheels in empty space have been moved to the trash bin of physics. They have been superseded by a powerful, beautiful, and restrictive symmetry that tells you that no aether is possible. Undoubtedly, this conclusion holds for the luminiferous aether much like the gravitational aether.

I hope that most readers are intelligent enough not to be manipulated by a slightly fashionable philosophical term "background independence" into believing these patently false and discredited ideas about the origin of electromagnetic and gravitational fields. No doubt, many proponents of loop quantum gravity have tendencies to revive Mach's principle, aether, and other things. But these are not debates that should excite 21th century physicists since they are completely unrelated to any experiments, observations, and conceptual problems with the current theories that explain the cosmos; these are debates whether we should forget everything we have learned in the last 100 or 300 years and return to the era when philosophical and religious dogmas, not experiments and their lessons, should dictate what is the truth. I guess that we should not.

Background independence of GR

Lee is trying to argue that GR is a "partly relational theory". The "partial relationism" stems from the diffeomorphism invariance. Well, from a rational viewpoint, diffeomorphism invariance is nothing else than an example of a gauge symmetry; an example that prevents us from defining local gauge-invariant fields/operators. It seems that it's the absence of local gauge-invariant fields/operators that Lee sees as the source of his "partial relationism". I don't care about these fancy words; the diffeomorphism group is nothing else than a gauge symmetry, much like Yang-Mills gauge symmetry. In fact, we know that Yang-Mills and diffeomorphism symmetries may be dual to each other in the Kaluza-Klein theory and string/M-theory; in the latter case, they can also transmute into each other. It is definitely a misunderstanding to assign the diffeomorphism invariance with a philosophically deeper role than the Yang-Mills symmetry has, for example. Both of them are local symmetries - redundancies of the description.

Also, if someone says that the diffeomorphism symmetry is qualitatively different from Yang-Mills symmetry and its philosophical implications are different and more far-reaching, he or she shows the flawed opinion that the space and the degrees of freedom associated with it are special. They are not special and in string/M-theory, we know that all degrees of freedom - gravitational as well as matter fields - are generating from the same fundamental starting point. This unification is an important philosophical paradigm: all degrees of freedom in a completely satisfactory theory should stem from the same starting point; the existence of one group of degrees of freedom should be deducible from others via consistency requirements and symmetries. Why is my principle deeper than Lee's or Leibniz's principles? It's because it's respected by a theory that is capable to describe the real world at a very fundamental level. Leibniz's are just words that are - as far as we can say - simply wrong and the evidence for his words is purely sociological.

On page 13, Lee also argues that there is no kinematics without dynamics in GR. Well, it's because the diffeomorphisms are able to mix space (kinematics) and time (dynamics) almost arbitrarily. Note that this important rule is also violated in loop quantum gravity. Its proponents argue that it is perfectly OK to study kinematics first, and pretend that the results are independent of dynamics (about which they know absolutely nothing). It's not OK in a generally covariant theory as explained above; the ability of loop quantum gravity to separate kinematics from dynamics reflects its struggle with the time-like diffeomorphisms that will probably never be well-defined in the theory.

Lee says many statements that can easily be seen to be flawed. On page 13, he says that if we construct a physical description of GR, Leibniz's "identity of indiscernible" will be respected. However, light-cone gauge string theory in the Minkowski space is a completely physical picture, but it still has non-trivial global symmetries that can transform a state into an analogous, but different state. A similar statement may also be said about the AdS/CFT correspondence or Matrix theory (which is similar to the light-cone gauge example); in both cases, the diffeomorphisms are also removed but global symmetries survive.

On page 15, Lee argues against perturbative quantum general relativity but his arguments actually seem to be directed against perturbative general relativity itself (without the word "quantum") because the word "quantum" plays no role in his arguments. The reality is that perturbative general relativity is the most important technical tool to study it - one that was instrumental in deriving all major predictions of GR such as the gravitational waves, Mercury's perihelion precession, bending of light, gravitational redshift, and others. The same perturbative techniques are also critical in the investigation of the quantum theory; they allowed Hawking to calculate his radiation and the details of his and Bekenstein's black hole thermodynamics; they tell us that gravitons must exist; they inform us that they become strongly coupled at the Planck scale where a UV complete theory (string/M-theory) must take over. Once again, virtually all tested and reliable conclusions of GR at the classical and quantum level could not have been derived without the help of the perturbative method.

On the other hand, there are no successes whatsoever of the approaches that Lee wants to call "non-perturbative approaches". The main problem is that they don't care about physics, experiments, and the new principles that are revealed by them; they prefer philosophical dogmas from the 16th century. It is a waste of time to discuss these "non-perturbative" speculations in detail. In all cases (causal set theory, loop quantum gravity, triangulation models), the speculations are based on the naive picture of space as being composed of infinitely sharp points - like in the classical theory - which are moreover exactly discrete. All these approaches make incredibly strong assumptions about the physics at the Planck scale whose probability to be incorrect safely exceeds 99.9999999999%; all of them belong to the discredited category of "gravitational aether theories" and no 16th century philosophical principle is strong enough to transform this intellectual waste into a topic for a meaningful physical debate in the 21st century.

Background independence in string/M-theory

This subsection starts with the statement of the physicists that physics around a particular background of string theory may be studied without a background-independent formulation of the theory. This statement is obviously correct as shown by Matrix theory and especially the AdS/CFT correspondence. Lee responds with a quip (or a serious assertion??) that it is not clear whether the AdS/CFT correspondence is a valid conjecture. After 4000 papers of agreements, "no comment" seems to be the only plausible reaction to Lee's speculation.

There is no doubt today that many superselection sectors of the string/M-theory Hilbert space admit a description in terms of theories that are completely well-defined. Locally, we may move into different places of the configuration space (or the landscape). Physics of "other backgrounds" is always, to some extent, encoded in every background dependent description of string/M-theory.

What we don't like is that the descriptions depend on the starting point too strongly. It would be much better to have a universal description that treats all places in the landscape on par with others. Such a description is likely to make the spacetime locality and causality more manifest, too. When a background-independent description of string/M-theory is found, it will provide us with a global view on the landscape. If there are any special places in the landscape, we should see them. The transitions between the different places of the landscape during the cosmological evolution would probably become well-defined mathematically. A background-independent formulation would also be more powerful in revealing new subtle inconsistencies or instabilities of particular backgrounds.

Most of us dream about a background-independent formulation of string theory; but once again, we don't need it to study a particular background (superselection sector) of string theory. If Lee really predicted that one cannot deduce physics of a larger class of backgrounds if we start from a background-dependent description, then his prediction has already been safely falsified.

Relationism and reductionism

I don't understand the logical flow of the discussion that starts on page 25. Lee mentions the importance of emergent phenomena for complex systems; he says that it is not a contradiction to reductionism but rather a "deepening" of it. There is no justification. Common sense dictates that the more role emergent phenomena play, the less powerful reductionism becomes. While I believe that reductionism is a generally valid idea and it is always just a matter of approximation to rely on emergent phenomena, it's impossible to agree that Lee has justified that the emergent phenomena are "deepening" reductionism.

For string/M-theory, Lee postulates three principles that - as he believes - are widely believed: unification, uniqueness, maximal symmetry. Unification means that all elementary degrees of freedom in the theory are manifestations of the same elementary entity; one group of the degrees of freedom can't be removed without destroying the structure. Lee says that the elementary entity in string theory "is" a string - which is somewhat perturbative, obsolete interpretation - but otherwise he's right. I have already discussed this principle above.

The second principle is uniqueness: the right description of all the interactions and particles is unique. Although Lee connects this principle with insults such as the adjective "postmodern", there is no doubt that there can't be two fully correct but different theories that describe reality. Two theories may be exactly equivalent; then we call them one theory. If they're not, there must be a difference between them, and an accurate enough measurement is sufficient to distinguish which of them is correct. Lee's doubts about uniqueness suggest that even if we found the ultimate description of string/M-theory that accurately predicts the particle masses etc., Lee would object that the correct theory can still be a different one. In this hypothetical situation, I would find any doubts to be a bizarre kind of craziness. Also, our experience suggests that it becomes increasingly clearer to decide whether a theory is a correct one as we approach to the more fundamental layers of reality. And the theories become more unique.

The third principle of maximal symmetry has not become a component in the active, successful research yet. One thing is grand unification: the gauge group in Yang-Mills theory should be as simple (technically) as possible. Another thing is its generalization to the whole physics; this has not led anywhere so far. One must distinguish gauge symmetries and global symmetries. A gauge symmetry is a redundancy of a description, not a property of a physical system. It depends on the description and equivalent descriptions of the same physics may come with different gauge symmetries (AdS has diffeomorphisms; CFT may have a Yang-Mills symmetry). The representation group of a gauge symmetry is physically irrelevant because the trivial singlets are the only allowed physical states.

Global symmetries are different (although they can arise as a subgroup of "large" transformations in the group of gauge symmetries). Their representation theory is very important because the physical states form their representations that don't have to be trivial. But I don't know a reasonable physicist who is trying to maximize the global symmetries. We know what they can be - for example, the Poincare group. The possibilities for global symmetries are very limited in string theory because a global symmetry is typically extended into a local symmetry. For example, a symmetry current on the worldsheet may be multiplied by "del X" to create a vertex operator for a gauge boson. This gauge boson implies that the symmetry was actually a local one, at least perturbatively. For rotations and translations, this means that string theory always contains spacetime diffeomorphisms and gravity. For other global symmetries, the prescription also works. Whether or not non-singlet states are allowed depends on dynamics (whether or not a gauge field is confining or not and whether it is spontaneously broken, for example). In a sense, I agree with Lee (page 27) that the precise identification of the (global) symmetry group depends on the background; it is a background-dependent question.

As we move through the moduli space, the natural symmetry that we imagine to be "fundamental" is changing. Heterotic strings on a circle may start with an E8 x E8 symmetry; one may adjust the Wilson lines and get to a point with an SO(32) symmetry. Both of them are 496-dimensional groups that are not contained in one another; they are equally profound, in a sense. There does not seem to be any natural finite-dimensional group that contains both; the full "stringy gauge invariance" seems to be the only conceivable unifying framework.

The comments about the global vs. local symmetries above are valid for the theories as we know them today. If a very large symmetry is relevant for the theory of everything, something about the separation to local and global symmetries must be generalized. Morally, it is true that the unified structure of string theory also unifies its symmetries, but it is harder to see technically how a particular large group could be relevant for the whole picture and why it would be exactly this group and not others. The intriguing idea to get "all of physics" from one very large group (such as one of the groups beloved by Thomas Larsson) remains an unsuccessful speculation.

There are errors in Lee's reasoning on page 30 and around that are too numerous to enumerate. Lee does not distinguish effective theories and UV complete theories; he claims that there are no good interacting quantum field theories above 4 dimensions (what about the (2,0) in d=6?) and so on. I don't know how anything reliable can arise from this philosophizing if one half of the input is just plain wrong. In my opinion, it is enough to overlook one error in order to destroy an argument. Whether or not a 6-dimensional quantum field theory may be UV complete and interacting is an important question, and the answer is Yes. It may not be an expansion around a gaussian fixed point; but it is a consistent theory with operators and their correlators nevertheless.

Fortunately, these technical points are completely independent from the general discussion about the anthropic hope, which is why I can easily agree with Lee's comments about the anthropic hope once again.

In the following section, Lee unifies relationism not only with reductionism but also with Darwin's theory. While I also enjoy these deep ideas about "metaunification", let me admit that similar constructions proposed by others usually look weird to me. Natural selection could possibly share something with relationism but it is definitely too vague to be of any use. Incidentally, Lee's prediction that the parameters of our Universe are optimized for black hole prediction has been safely falsified. It is easy to adjust some parameters in such a way that we produce many more black holes than those seen around.

Cosmological constant puzzle

It's interesting to see a debate about the C.C. problem that is based on four speculations all of which seem completely vacuous and flawed. Statements such as "the C.C. problem is just an artifact of the evil background-dependent thinking" look ridiculous. No doubt, the background dependence is also responsible for the latest terrorist attacks. But such an emotionally loaded combination of words does not show how to calculate the right (tiny) value of the cosmological constant in a theory that contains the known particle physics - which is the true content of the C.C. problem. Some people apparently think that a solution to the C.C. problem means to construct a grammatically correct English sentence that contains a quote by a 16th century philosopher as well as the happy end that the C.C. problem is eventually solved. I beg to differ.

"Relational quantum theory"

On page 37 Lee starts an attack against the quantum theory itself. It's hard for me to read this kind of material. There is one valid point - that Bohr argued that the boundary between the "classical observer" and the "quantum observed object" may be drawn more or less anywhere which was not satisfactory. Today, we solve this question by decoherence that may be used to calculate the scale at which the classical concepts become a good approximation and the quantum coherence and interference disappears because of the interactions with the environment. Decoherence is a part of the modern neo-Copenhagen interpretations, especially the picture based on Consistent Histories.

The emergence of the classical world from the universal framework of quantum mechanics was a well-defined puzzle associated with the interpretation of quantum mechanics - one that has been solved. It is much harder to see which problems Lee is trying to solve now but I suspect that they are not my problems.

Lee combines various valid but usually invalid objections against various interpretations of quantum mechanics with relationism and cosmology. Because the length scale above which the meaning of the text seems to evaporate is around 1-3 sentences, I can't unfortunately say anything nice about these comments. As far as I can say, "relational quantum theory" is an incoherent conglomerate of weird assertions about quantum theory from people who have never understood it and who kind of confuse the lessons of relativity with the lessons of quantum mechanics. Concerning the "relational approaches to go beyond quantum theory", let me just state that as far as I can say, there exist no approaches to go beyond quantum theory (certainly not "relational ones") and all statements I have seen that claim the opposite are rubbish.

While the word "rubbish" may sound harsh, you should not forget that if you rearrange the electrons and nucleons in rubbish properly, you may obtain anything, including a piece of gold. This is what many of us should try to do with these questions.

See also Moshe Rozali's comments about background independence that are pretty much equivalent to mine.

Rich aliens from strings

Totday, the India Daily Technology Team has informed the large Asian country that

• The superstring theory in contemporary physics proves the existence of parallel universe with many higher dimensions where advanced alien civilizations prosper.

Actually, this sentence is the title.

Rich aliens seem to be one of the first practical application of string theory; they may live in a new kind of landscape. ;-) Their existence has also been shown by "rich spectroscopy at the Large Hadron Collider", our Indian colleagues argue and demonstrate it by a photograph of a fully operational collider. After the article in India Daily, The Reference Frame is the second source that informs you about the great news - and moreover tells you that you should not accept the news uncritically. ;-)




You should not think that India is the only place where such encouraging news occur. Yesterday, Canada was told that the work of Donald Coxeter from Toronto found applications in the Nobel-prize-winning carbon 60 molecule and string theory. A nice combination.

Also yesterday, another article about the liquid behavior of the "matter produced by Big Bang" appeared and the liquid behavior of the quark-gluon plasma may be "explained by some versions of string theory". Details are not specified.

The Texas GOP came unraveled yesterday

I don't post about the goings-on of the Texas Legislature very often, because so many others do such a good job, but this diary from Glenn Smith of Drive Democracy.org is particularly cogent in its assessment of the fifth failure in four years of the all-Republican leadership to come up with a plan to finance public education:

The GOP majority in the Texas House of Representatives today fell apart, its party discipline destroyed by the stink of corruption that permeates the Bush era in Texas and across the country.

If Texas had icebergs, this would be the tip of one. I'm not talking about Karl Rove's adulterous behavior.

I'm talking about the stinging defeat suffered by the Texas GOP on the floor of the state House today. GOP leadership, helped to election by illegal corporate contributions, watched helplessly as the Democratic minority and a few frightened Republicans voted down bills that 1) raised taxes on the middle class; 2) Cut taxes for Big Insurance and other special interests involved in the scandal; 3) Stiffed school children and teachers under the guise of education reform.

This is no small matter. It should be pointed out that in the early 1970s, a political scandal called Sharpstown surfaced just ahead of a national political scandal called Watergate. By 1976, Jimmy Carter could carry Texas.

The talking points are simple: Texas Republicans are trying to raise taxes on middle class Texans and devastate public education so they can do what they were ordered to do when they accepted the illegal bribes: cut taxes for the people who paid the bribes.

Several corporations have been indicted. So have some staffers who were allegedly involved in the scheme. Tom DeLay, who lives off his aura of power, says he was powerless over a scheme that invoved his committee and its money and its contributers and that advanced his Congressional redistricting scheme. A grand jury, holding all the cards, is still meeting.

Corruption is bad enough. But when corruption is tied to taxes, education and other close-to-home issues, there's going to be trouble.

That's why some Republicans are rebelling. That's why Texas House Speaker Tom Craddick, always in over his head with this job, might be losing his head and his job. He's asked his Republican members to cast dozens of career-threatening votes just so he can tell his Bosses at Big Insurance that he was a good little boy who did what he was told.

All of the MSM -- the Texas newspapers and broadcast affiliates -- are far less revealing about this collapse of leadership, and what it means for Texas children.

I wouldn't expect them to catch up to the story, either.

Rove is about to get some of his own medicine

Via Daily Kos, from Radar Online:

For years, political insiders in the Lone Star State have whispered about Rove’s close friendship with lobbyist Karen Johnson, a never-married, forty-something GOP loyalist from Austin, Texas. The two first became close when Johnson sat on the board of then-Governor George W. Bush’s Business Council over a decade ago. Their friendship reportedly deepened after Bush appointed Johnson—a little-known spokesperson for the Texas Good Roads Association—to a seat on his Transportation Department transition team in 2000. The plum appointment enabled Johnson’s lobbying firm, Infrastructure Solutions, to snare such high-paying clients as Aetna and the City of Laredo. Sources say Johnson now frequently travels between Washington D.C. and Austin, where she frequently appears at Rove’s side at parties and unofficial functions.

Although there is no evidence that their relationship is anything but professional, the close association between the married White House aide and the comely lobbyist has long raised eyebrows in conservative Texas circles. Asked about the pair, a prominent political journalist who has written extensively about Rove says, “I’ve heard the stories, but I would never write about Karl and Karen. If you want to keep your job as a reporter in Texas, you make believe you don’t see them together.”

In the post-Lewinsky era, Washington’s press corps has mostly avoided reporting on the private lives of public officials. But as the political climate in the capitol grows more poisonous, Rove’s close friendship with the lobbyist has attracted increased scrutiny from opponents eager to prove that Bush’s dirty trickster is sitting on some dirty laundry of his own.

And kos adds:

In a fortuitious coincidence, Jerome and I have just finished interviewing a long-time Texas political writer here in Austin who says that Rove is absolutely having an affair with Karen. Rove is married and has a teenaged son. According to this writer, Rove's wife is a hardcore liberal. "I don't know how he and his wife get along," he said.

Well, quite obviously, they do not.

In a more discreet political era -- say, just a few short years ago -- I might have said that a politician's personal private life is none of our business.

But, as we are constantly reminded, 9/11 changed everything.

Meet Texas' newest precinct chair

Well, maybe not the newest, but one of them, as I accepted the appointment yesterday.

In order to maintain a tiny shred of anonymity, I won't identify it by number, but if you've been reading here and elsewhere I post for any length of time you can figure out a lot; I will tell you that my precinct flips conventional wisdom about the city I call home on its head. In fact it is even more liberal than I suspected -- in 2004 it went more than 60% for John Kerry.

And there's plenty of room to improve upon those numbers.

Heh.

Strings as Microsoft

This is my (first) reply to the discussion over at cosmicvariance.com under Sean's article called "Two cheers for string theory", especially the article itself.

There are many points in the text that I agree with and the author seems to have a remarkably sane idea what string theory is all about even though he is not a practitioner. There are other, more technical points, where corrections are necessary. Sean has not really considered the implications of the last 10 or 20 years in string theory but most of the non-professional readers of their blog misunderstand these implications as well, so it does not seem to matter and the readers are satisfied.

No doubt, it would be more encouraging if more than string theory as of 1985 presented by a non-string-theorist was needed for a full satisfaction. But one should not forget that there are many people, often outside the blogosphere, who care about the difference between string theory as of 1985 and 2005.

Let me start with some comparisons mentioned in the discussion.

String theory is Microsoft of quantum gravity. Unlike Robert, I have no serious problems with this comparison. Microsoft is more about success and competition while string theory is about the lasting intellectual value. But the degree to which string theory dominates the research in quantum gravity is analogous to the extent to which Microsoft dominates the world of operating systems. On the other hand, our loop quantum gravity colleagues should definitely feel flattered if someone compared them to the Apple or Linux of quantum gravity.




The reason is that the Apple computers more or less work, and sometimes the same thing holds even for the Linux computers.

Microsoft is gonna release a new operating system in 2006; a successor of Windows XP. It used to be called Longhorn, but on Friday they announced that it will be called Microsoft Windows Vista. I am looking forward to see this system, and I hope that string theory will offer something comparably striking by 2006. Meanwhile, many of us will continue to admire Microsoft and Bill Gates whose acts have been critical for the PC industry. When I learned that the BASIC for Commodore 64 - a home computer we played with as kids - was made by Bill Gates, my admiration doubled. And it did not disappear even when Bill Gates praised the brand new type of capitalism in China (formerly known as communism) and helped the Chinese bastards to ban MSN blogs containing the word "democracy".

Don't get me wrong: Linus Torvalds and Steve Jobs are also amazing guys! It would be harder to say the same thing about all the activists whose goal is to eliminate commercial software and force everyone to use their favorite semi-functional open source software.

String theory vs. QFT and Standard Model

Another comparison Sean offered was between string theory and quantum field theory. His goal was to suggest that string theory was not a particular model - such as the Standard Model - but a whole framework - such as quantum field theory. Definitely, string theory provides us with a new set of mathematical tools and concepts to study spacetime physics that goes beyond quantum field theory.

But in a specific technical sense, string theory is more analogous to the Standard Model, indeed. It's because string theory is one theory. While different quantum field theories are physically disconnected - although they can be mathematically similar - different backgrounds in string theory are solutions of the same underlying equations. We should imagine the Hilbert spaces of backgrounds in string theory to be unified into one Hilbert space. Moreover, the conditions of one background can usually be locally reconstructed in another background.

The haystack (or landscape) of these classical solutions of string theory is much more complex than in the case of the Standard Model, but the analogy holds. In fact, string theory is an even more specific model than the Standard Model; the Standard Model (with neutrino masses) has about 30 free parameters. String theory, on the other hand, is a completely unique theory and it has no free, continuous, adjustable, dimensionless parameters.

In some sense, string theory may look as a framework and a loose network of new ideas. But in a very technical sense, string theory is a completely rigid and unique conglomerate of these new ideas.

Sean's argument that string theory is a framework, not a specific model, is being used to justify the opinion that string theory does not have to predict particular numbers that can't be extracted from the Standard Model and GR. From a general intellectual or mathematical viewpoint, I agree with this thesis. String theory is continuously generating a lot of new mathematical ideas and new physical intuition that helps us to solve mathematical problems and compute things in new ways. It is also an amazingly consistent mathematical structure that is deeply rooted in physical reasoning. This itself justifies the research.

The value of a unification of GR and QM

From a physics point of view, I disagree with Sean's comment that string theory is justified as a physical theory even if it makes no new predictions. He emphasizes that string theory should be sold as the leading candidate to unify GR and QM. That's fine. But the only physical reason why we need to unify GR and QM is the fact that our world apparently respects both the postulates of QM much like it contains phenomena of GR. In other words, we need to unify them because we need to make predictions for our real world where electroweak, strong, and gravitational forces operate together and happily.

A consistent reconciliation of QM and GR in d=4 or higher turns out to be an interestingly constrained and difficult mathematical task whose solution is most likely unique up to dualities and equivalences. The solution is called string/M-theory. But we would never know that such a reconciliation is an interesting problem if we did not see both GR and QM in the world around us. And the only useful and physically valuable result of such a reconciliation are new predictions - qualitative or quantitative. For the reconciliation to be meaningful, we must be able to say something that the previous theories were silent and ignorant about. In particular, this includes the "overlap" regions where both GR and QM are necessary, such as the black hole singularity and the Big Bang.

There seems to be no argument about the fact that string theory has provided us with new sensational insights into many corners of mathematics and mathematical physics: into geometry of Calabi-Yau spaces (including mirror symmetry), equivalences between objects and phenomena that a priori look completely different (dualities), holography and the AdS/CFT correspondence, the role and fate of fields such as tachyons, geometrical realization of many mathematical systems that looked non-geometrical before, and so on.

It has also given us many new ideas how new interesting physics "behind the corner" may possibly look like and in 2005, most stringy as well as non-stringy phenomenologists admit that the majority of new good ideas for model building in the last 10 years came from string theory. We don't need to argue about these things; everyone who wants to be "in" tries to extract some valuable insights from the reasoning discovered by string theorists.

Value for physics as opposed to mathematics

But all these things are victories in physically inspired mathematics and the search for better mathematical tools to study physics. They're not victories in physics itself. I consider string theory to be more than just a miraculous generator of new mathematical insights about objects inspired by physics. I believe string theory is a new, deeper theory to accurately describe actual physical phenomena; probably a theory of everything. By a "new" theory, I mean that it is not physically equivalent to the previous theories such as the Standard Model (an example of a QFT), but it contains all of their wisdom and something more.

I don't see what the unification of GR and QM would be good for if it did not allow us to calculate new numbers about a world containing both GR and QM, at least in principle. Notice that this is the same comment that is emphasized whenever I explain why the attempts of loop quantum gravity to unify pure GR with QM are not only failing but also misguided from the very beginning. It is not exactly just some abstract QM that we want to unify with pure GR and we have no experimental evidence that pure GR should be compatible with pure QM without other forces: we want to unify the well-known quantum phenomena - namely gauge theories with fermions - with gravity.

Loop quantum gravity can't do it because these sectors remain independent, even in the most optimistic case in which the Standard Model is successfully added to LQG with the right low-energy limit. String theory does achieve this goal because gauge theories, fermions, and gravity are all parts of its low-energy limit. But in order to achieve the goal fully, it should also be used to derive the right spectrum of particles with the right parameters either from no input or from a smaller set of assumptions than required by the previous theories.

Concerning loop quantum gravity, I also disagree with another point of Sean: that all of us should offer our support to loop quantum gravity and other problematic directions in order to create an environment of competition. In my opinion, scientists should provide hints where to go according to their best knowledge. My best knowledge about loop quantum gravity implies that it is a misguided approach to physics. There undoubtedly exist people with a different opinion but it is impossible to lend your support to a particular human activity just because some other people like it. These people may only like it because a third group of people likes it - and the source of the love may remain obscure. That's wrong. Scientists' responsibility is to offer their independent opinion. Mine is that loop quantum gravity is a wasted time and money. And social-engineering of competition is plain wrong.

Ann Nelson and Occam

Occam's razor dictates me to agree with Ann Nelson in one point: if the prediction of the parameters or other numbers absent in the Standard Model is impossible, then the Standard Model should be favored as a physical description of reality because it is simpler and requires the same (or smaller) number of input parameters as the stringy landscape picture, for instance. My feeling is that some colleagues of ours truly love mathematical derivations and translation of one kind of physics into another kind of physics; even if the amount of predictions agrees, they will prefer a starting point that is as different from the final outcome as possible and that is as complex as you can get.

My opinion - and I suspect that the opinion of Ann Nelson and most phenomenologists as well - differs. A more convoluted starting point and a longer chain of reasoning from this starting point to the final result is only justified when either the explanatory power is extended, or the amount of parameters or independent assumptions and concepts is reduced.

String theory as we know it today may be used to calculate the Planckian scattering in some backgrounds. (Incidentally, for Peter Woit, the gravitational potential of an electron is "-M_e.G/r".) That's a stimulating progress, but the real victory in physics only occurs once we become able to calculate the Planckian scattering - the transition between low energies and the black hole creation - in the real world. The importance of this next step - to describe the effects in the real world - has become particularly pressing at the moment when we decided that the number of backgrounds in string theory is probably large, and therefore the collective predictions for all backgrounds are potentially highly ambiguous and essentially arbitrary until we find a selection principle. A larger number of critical points in the landscape does not mean that we should give up the goal to extract predictions beyond the Standard Model from string theory; it just means that the vacuum selection mechanisms will be a more important part of the full story than we had thought previously.

If the string theorists ever give up the task to calculate the numbers that can't be predicted by the previous theories, the string theory research should be moved to mathematics departments. Physics is about understanding the actual material physical world we live in. Mathematical beauty is a great thing, but for a physicist it should be just a hint that she is on the right track. It cannot be the ultimate justification of a proposed theory. Progress in physics always means that a larger number of phenomena can be calculated and predicted more accurately using a theory with less independent assumptions, defining concepts, and parameters.

String theory has the capacity to achieve this goal maximally, and if we transform ourselves into pessimists and fool ourselves by pseudo-arguments that the progress is impossible and that we should be even happy with such a postmodern and I would say scary expectation, we're gonna be in a big trouble.

Strings are just a piece

Also, another problem with Sean's text is that he paints string theory as we knew it 20 years ago or so. (It's not such a big problem at their blog whose typical readers who are not professionals - and some of those who are - are more interested about the YES/NO wars about string theory rather than the difference between string theory in 1985 and string theory in 2005.)

Today, string theory is not just a theory of strings. The perturbative approach to string theory based on one-dimensional elementary objects was a very fruitful point to start with, but we know today that it is far from being the whole story. The strings may be viewed as fundamental objects in the weakly coupled regime only; in other limits, other objects may "look" fundamental even though they were interpreted as solitons in the weakly coupled limit. In a recent article about the depth of ideas, I also explained that the very idea to replace point-like particles by strings is not deep. It only becomes a powerful idea once the special properties of two-dimensional conformal field theory are revealed.

In other words, when a person who does not understand conformal field theory in 2 dimensions at the technical level says that the idea to replace point-like particles by strings does not look deep to her but rather shallow and convoluted, I completely understand where she's coming from. But I would also like to tell her that if she learns how the relevant mathematics works, she will understand why strings are so special. But it requires a lot of calculations and the power of strings can't be obvious to a layman after 1 minute.

This point is rarely emphasized, so let me say it again. The laymen who consider strings as the elementary building blocks to be a shallow idea are correct at the beginning; but there is a lot of mathematical facts that can't be obvious from the very beginning that eventually make strings much more remarkable than one might have thought. This implies a recommendation for the laymen: slow down your far-reaching conclusions about string theory until you learn how its machinery works at the technical level.

Today, "string theory" is a kind of misnomer. The theory is based on many other concepts, too - but it does not make it less reliable. On the contrary. Clifford Johnson is very right when he disagrees with Sean and mentions that M-theory in 11 dimensions which has no strings is an equally valuable and qualitatively understood limit of the whole theory as the five superstring theories in 10 dimensions.

Point-like terminology

Sean mentions that he does not understand why the regular quantum field theories are said to be based on "point-like particles". It's because the quantum fields assign an operator to every point in spacetime. In string theory, it is different, indeed. For example, if you formulate string theory using the language of string field theory, you must assign an operator to every one-dimensional contour (string) embedded into spacetime. The number of degrees of freedom you see perturbatively is just much larger than in quantum field theory. (But at the very end, paradoxically, you end up with a holographic theory whose number of degrees of freedom is smaller than in any local point-like quantum field theory.) The fact that the operator at a given point can't be quite identified with the actual physical particle is an irrelevant technical complication that does not reduce the large technical difference between point-like field theories and string theory.

Wrong attempts to separate str-ing theory

Several participants in the discussion try to follow Peter Woit and divide string theory to the "good" stuff - new approaches of QCD including the AdS/CFT correspondence, insights about mirror symmetry - and the bad stuff - which includes the 10-dimensional and 11-dimensional vacua as the unifying starting point to include all of physics.

Only a person who is completely ignorant about the way how string theory works - and Peter Woit and Ohwilleke are not the only ones - can say something so absurd. There is no way to eliminate the critical dimension and all other basic insights about string theory from the other, "good" applications of string theory. For example, the best understood example of the AdS/CFT correspondence involves the N=4 super Yang-Mills theory. The dual bulk description is the AdS5 x S5 background of type IIB string theory. Note that the total dimension is 5+5=10, as always required in type IIB string theory. All the detailed features, including the excited type IIB strings and branes of all kinds, can be derived not only from the bulk description but also from the gauge theory defined on the boundary!

String theory, at least in the highly supersymmetric vacua with 8 or more supercharges, is a fantastically rigid theoretical structure that holds together perfectly. If someone says that one can preserve the successes (as enumerated above) of string theory without preserving everything we know about its critical dimension and the basic knowledge of stringy dynamics in 10 and 11 dimensions and the compactifications, then she or he only shows that she or he is uninformed about the very basic facts of the field. String theory simply can't be separated in this way. It would be similar to the attempt to remove photons from QED.

Strong leadership of supersymmetry

Possibly, there are many intellectual directions - bosonic string theory, non-critical string theory, topological string theory, the landscape approaches - that will eventually be considered to exist outside the realm of "the" string theory (or will be considered inconsistent because of some non-perturbative subtleties). By "the" string theory, I mean the theory that has the beauties and that is relevant for the real world. But the different phenomena and relations between physical insights about the supersymmetric vacua of string theory can't be undone, and they will always be essential for our understanding of many things, including holography etc.

The less we rely on spacetime supersymmetry, the less reliable the different dualities and relations are. For example, the holographic dual of pure QCD in 4 dimensions probably has a different bulk dimension than 10 or 11 and it may be called a non-critical string theory (it is an ambiguous task to define the number of tiny dimensions in a background of string theory; only the large and nearly flat dimensions can be counted without doubts). But it is also the case where the existence of a quantitatively predictive dual (bulk) theory is uncertain and where string theory has not told us too much - at least not too many quantitative results.

The maximally supersymmetric backgrounds - such as the N=4 gauge theory - are best understood, and one can show that the dual is not just some generic five-dimensional gravitational theory, but the ten-dimensional type IIB string theory on a very specific background. All details work. It is not possible to eliminate some known aspects of ten-dimensional string theory from this picture! While various other approaches to quantum gravity are incoherent and dividable conglomerates of ideas, string theory is united.

United we stand, divided we fall.

The very first GOP talking point

A summary of the trouble

... the Bushies are in over Leakgate, from Daily Kos:

Bloomberg is reporting that Rove and Libby both gave testimony to the grand jury that flatly conflicts with the testimony given by those they said they talked to.

We now know that the Top Secret memo most consistent with the talking points that Rove and Libby told reporters was seen in the hands of Press Secretary Ari Fleischer in the days before the leak occurred. And that he told the grand jury he never saw it.

And Steve Clemons has verified that John Bolton was one of Judith Miller's regular sources on WMD issues, and that MSNBC stands by its story that Bolton gave testimony to the grand jury about the State Department memo in question. Bolton, you may recall, has previously been identified to have been involved in the Niger uranium claims that Wilson's trip helped disprove ...

... the Bushies are in over the latest Abu Ghraib torture photos they're refusing to release:

On July 22, the Center for Constitutional Rights (CCR) denounced the latest efforts of the Bush Administration to block the release of the Darby photos and videos depicting torture at Iraq’s Abu Ghraib prison facility. On June 2, 2004, CCR, along with the ACLU, Physicians for Human Rights, Veterans for Common Sense, and Veterans for Peace filed papers with the U.S. District Court, charging the Dept. of Defense and other government agencies with illegally withholding records concerning the abuse of detainees in American military custody. Since then, the organizations have been repeatedly rebuffed in their efforts to investigate what happened at the prison.

In June, the government requested and received an extension from the judge stating that they needed time in order to redact the faces of the men, women and children believed to be shown in the photographs and videos. They were given until today to
produce the images, but at the eleventh hour filed a motion to oppose the release of the photos and videos, based on an entirely new argument: they are now requesting a 7(F) exemption from disclosure under the Freedom of Information Act to withhold law enforcement-related information in order to protect the physical safety of individuals. Today’s move is the latest in a series of attempts by the government to keep the images from being made public and to cover up the torture of detainees in U.S. custody around the world.

... and ...

The images, according to those lawmakers who have seen them, paint a picture of torture at Abu Ghraib far, far worse than most Americans have yet been willing to admit. Via the Boston Herald, May 8th, 2004:

Signaling the worst revelations are yet to come, Secretary of Defense Donald Rumsfeld said the additional photos show "acts that can only be described as blatantly sadistic, cruel and inhuman." ...

The unreleased images show American soldiers beating one prisoner almost to death, apparently raping a female prisoner, acting inappropriately with a dead body, and taping Iraqi guards raping young boys, according to NBC News.

Republican Sen. Lindsey Graham of South Carolina said the scandal is "going to get worse" and warned that the most "disturbing" revelations haven't yet been made public. "The American public needs to understand, we're talking about rape and murder here," he said. "We're not just talking about giving people a humiliating experience; we're talking about rape and murder and some very serious charges."

And from Seymour Hersh:

The women were passing messages saying "Please come and kill me, because of what's happened". Basically what happened is that those women who were arrested with young boys/children in cases that have been recorded. The boys were sodomized with the cameras rolling. The worst about all of them is the soundtrack of the boys shrieking.

Note these links are from 2004. The administration, and several members of Congress, have known about these additional abuse cases, including photos and video not released to the public, for over a year. And yes, the rest of the world already knows.

So we've been sodomizing children. In the name of freedom.

Can you stand some more?

The White House on Thursday threatened to veto a massive Senate bill for $442 billion in next year's defense programs if it moves to regulate the Pentagon's treatment of detainees or sets up a commission to investigate operations at Guantanamo Bay prison and elsewhere.

The Bush administration, under fire for the indefinite detention of enemy combatants at Guantanamo Bay in Cuba and questions over whether its policies led to horrendous abuses at Abu Ghraib prison in Iraq, put lawmakers on notice it did not want them legislating on the matter.

"If legislation is presented that would restrict the president's authority to protect Americans effectively from terrorist attack and bring terrorists to justice," the bill could be vetoed, the statement said.

So on the one hand, the Bush administration is blocking the release of the photographic proof of the most horrific war crimes committed in U.S. military-run prisons. And on the other hand, they are threatening to veto any attempts by Congress to establish laws banning such torture -- or even to investigate the torture already documented.

Had enough? Apparently, some have:

A rapid series of car bombs and another blast ripped through a luxury hotel and a coffeeshop in the Egyptian Red Sea resort of Sharm el-Sheik early Saturday, killing at least 83, a hospital official said. Terrified European and Arab tourists fled into the night, and rescue workers said the death toll could still rise.

It was another day of high tension, disruption and fear on the London Underground. The union for subway and bus drivers said workers would be justified in staying away from work if the government fails to take more precautions to make the operators safe. "I think they're going to strike again," commuter Warren West, 27, said of the bombers. "I think they're doing to London what's happening in Iraq."

Is George Bush still making everyone feel safe?

Congressional hearings on Leakgate

are currently being televised on C-SPAN3.

On a relevant tangent, it appears that special prosecutor Peter Fitzgerald is focusing on crimes that can be easily proven, namely perjury and obstruction of justice, against two of the highest White House officials, presidential advisor Karl Rove and Dick Cheney's chief of staff Lewis "Scooter" Libby.

Now the questions become familiar, echoing back from history: what did the Vice President know, and when did he know it? And the President?

I was fourteen years old during the summer of Watergate and the last time a Republican administration collapsed under the creaking weight of its own corruption. The similarities between that scandal and this one -- sordid political dirty tricks taken to a criminal extreme for the sole apparent purpose of blackmailing a political opponent -- seem today to pale in comparison to 1770 dead American soldiers, thousands of innocent Iraqis killed as collateral damage, billions of dollars wasted in every direction and even misplaced, and the reputation and goodwill of the United States of America ruined.

And as of this post, not a single elected Republican official has yet broken ranks with this White House over this scandal, these lies, these crimes.

That's another difference between Watergate and Leakgate.

There is no member of the President's political party that has yet summoned the strength, the will, the courage, to speak out. No Howard Baker this time around. Eventually as this scandal continues to unfold -- sooner or later -- that will change, and our nation will be the better for that man or woman's bravery.

I think we're still many days away from that day.

Hawking and unitarity

The previous blog article about the very same topic was here.

Stephen Hawking who may currently be the world's most famous applied string theorist among the public has finally submitted a paper that many of us were eagerly expecting for a year or two. The paper is titled "Information Loss in Black Holes" and its preprint number is hep-th/0507171. Because it is less than 5 pages long, I recommend you to read it.

On the first page, he summarizes the history of the information loss puzzle. In 1967 the no-hair theorems started to appear: the black holes are classically more or less unique solutions determined by a few parameters. Because they don't have any hair, they can't wear any haircuts that would distinguish them from other black holes with the same value of conserved quantities; they don't have any features that could give them a large entropy.

This is strange because the black holes seem to be the final outcome of a gravitational collapse, and according to the 2nd law of thermodynamics, the final states should maximize the entropy. The apparently vanishing entropy seems to contradict this law. However, the black holes in the classical theory are eternal and we may envision the information as being stored inside the hole; it is just not accessible to the folks outside.

This argument fails in the quantum theory because of the line of reasoning pioneered by Jacob Bekenstein and Stephen Hawking. Black holes eventually evaporate, via the Hawking process, which eventually uncovers all the details of their interiors. The nonzero temperature may be used to derive their entropy via the equations of thermodynamics; the entropy happens to be proportional to the horizon's area (for large black holes; the extensive progress in determining all the corrections from string theory is discussed elsewhere), as first predicted by Bekenstein.




However, Hawking's semiclassical calculation leads to an exactly (piecewise) thermal final state. Such a mixed state in the far future violates unitarity - pure states cannot evolve into mixed states unitarily - and it destroys the initial information about the collapsed objects which is why we call it "information loss puzzle". A tension with quantum mechanics emerges.

There have been roughly three major groups of answers that people proposed.

1. One of them is essentially dead today; it is the remnant theory. It argued that the black hole does not evaporate completely. Instead, a small light remnant with a large entropy remains after the evaporation process - and this remnant is what preserves the information. This approach is highly disfavored today because such small seeds simply should not be able to carry large entropy (because it violates holography). Moreover, this approach does not save unitarity anyway because the scenario still assumes the thermal radiation to be in a mixed state.
   
2. The other two general answers are obvious. One of them says that the information is lost, indeed. The qualitative features of Hawking's semiclassical calculations - the evolution into mixed states - survive in the exact analysis, too. Such an approach is popular among the General Relativity fundamentalists who believe that the fabric of spacetime is exactly what we think it is classically; causality in particular must be exact and no information can ever get out from a black hole. I formulated the argument in a way that makes it clear that it looks dumb to me - especially today when we know that topology of space may change and that black holes exist in unitary backgrounds of string theory. The Hawking process itself is an example of a violation of the strict rules of locality and causality by black hole physics!
   
3. The last answer, the only one that has always respected the principles of the 20th century physics, says that the information is preserved in the same way as in any other process in the world - burning books is an example. (Only later, I noticed that Hawking has independently chosen the very same example.) When we burn books, it looks as though we are destroying information, but of course the information about the letters remains encoded in the correlations between the particles of smoke that remains; it's just hard to read a book from its smoke. The smoke otherwise looks universal much like the thermal radiation of a black hole. But we know that if we look at the situation in detail, using the full many-body Schrödinger equation, the state of the electrons evolves unitarily.
   
   The same thing must hold for black holes. And the feeling that such a transfer of information is impossible because of the horizon is just an illusion; it is an artifact of the semiclassical approximation that paints the rules of locality and causality as more strict than they are in the full theory. Locality and causality are, in general, approximate emergent concepts that appear in the (semi)classical limit. The power of the full theory of quantum gravity to violate locality and causality in a subtle way is manifested whenever horizons develop, and it is responsible for the conservation of the information.

Note that the conservation of the information is the only answer that can be acceptable for a physicist who treats the postulates of quantum mechanics seriously. No doubt, the postulates of quantum mechanics seem rigid and un-modifiable, while the exact degrees of freedom and terms in the Lagrangian that describe general relativity are flexible. The quantum mechanical postulates have a higher priority, and they tell us that the information must be preserved in the details of the nearly thermal Hawking radiation that remains after the black hole disappears.

While Stephen Hawking has believed that the information was lost - and he has made bets of this kind - he eventually switched to our side in the summer of 2003 or 2004 (I am uncertain now). As you could hear from CNN and other major global new agencies, he officially admitted that his opinion was incorrect. The deep insights in string theory have convinced him that John Preskill was right and the bet is lost; Hawking gave an encyclopedia to Preskill as promised.

Among these insights that have convinced Hawking, you find Matrix theory and especially the AdS/CFT correspondence. Gravity in asymptotically AdS spaces has an equivalent description in terms of a conformal field theory living on its boundary. This conformal field theory is manifestly unitary and has no room for destruction of the information. This answers an equivalent question about gravity, too.

This brings most sane physicists to the opinion that the information is preserved and gravitational physics is not that special after all. But it does not give us a quantitative, calculable framework that would explain how does the information get out of the black holes and what do these subtle correlations that remember the initial state look like.

Hawking's recent solution

Hawking has announced that he had solved the problem. The main ideas of his solutions are the following ones:

• The scattering S-matrix is the main "nice" observable that should be calculated in a theory of quantum gravity. (I fully agree.)
• The scattering does not prevent a black hole from being formed, but such a black hole is just like any other intermediate state or resonance. (I fully agree.)
• The thermal nature of the resulting radiation is a consequence of an approximation (that becomes accurate for large black holes) but there is no qualitative difference between black hole intermediate states and other intermediate states; the transition if smooth. (It was actually just me who formulated this point in this way.)
• Just like in quantum field theory, the Euclidean setup combined with the Wick rotation is an essential technical tool to do the calculations; Hawking refers to Euclidean gravity as the "only sane way" to do quantum gravity. In the gravitational context, this approach was promoted and improved by Hawking and Gibbons. In fact, the Euclidean approach may be even more important in quantum gravity than it is in quantum field theory and its procedures may represent am even larger fraction of the derivations in the gravitational context. (I agree, and as far as I know, the people who disagree - such as Jacques Distler - have not offered any rational and valid arguments so far.)

OK, so Hawking tells you to calculate the S-matrix by a Euclidean path integral over topologically trivial configurations (spacetimes) - those that are continuously connected to the empty spacetime. Such a process may involve a production of a large number of particles in the final state which is a hallmark of an intermediate black hole. Once you calculate the Euclidean S-matrix, you Wick rotate the results to get the amplitudes for the Minkowski signature.

Note that we have only included the topologically trivial spacetimes and this is a good choice that preserves unitarity.

On the second page, Hawking proceeds with some technical subtleties. He wants to allow strong gravitational fields to occur even in the initial and final states, it seems. (It does not seem necessary when one talks about the generic S-matrix elements but it is conceivable that these strong fields appear in the Euclidean spacetime anyway.) With strong gravitational fields in place, one can't meaningfully define the wavefunction at time "t" because there is no preferred diff-invariant way of slicing the spacetime.

Hawking solves this by a seemingly bizarre operation. He calculates a partition sum with periodic Euclidean time instead of the transition amplitude; it is not 100% clear at this point how will he introduce the initial and final states to this setup. (Note that the Euclidean time is spacelike and it should therefore not be interpreted as a source of the usual violation of causality.) Moreover, this partition sum has a volume-extensive divergent factor. Hawking regulates this infrared problem by introducing a small negative (anti-de-Sitter-like) cosmological constant that does not change local physics of small black holes much.

He obviously deforms the picture into an AdS one in order to get a background that is as well-defined as the usual AdS/CFT backgrounds in string theory. Hawking states that because we are making all measurements at infinity, we can never be sure whether a black hole is present inside or not.

This looks like cheating to me; equivalently, it suggests that no true solution is being looked for. Of course that if we only work with the boundary degrees of freedom, we will see no unitarity violations and no problems associated with the black hole dynamics. It's simply because all these things are encoded in the CFT which is unitary. The true surviving question is how is this unitary description reconciled with the bulk interpretation in which a macroscopic black hole is demonstrably present and has the potential to cause information loss headaches.

Hawking does not have a working convergent path integral beyond the semiclassical approximation, but let us join Hawking and pretend that this problem is absent. He computes the partition sum over geometries whose boundaries are topologically S^2 (the sphere at infinity) times an S^1 (the periodic Euclidean time) at infinity; he works in four spacetime dimensions. There are two simple spacetimes with this boundary: B^3 times S^1 is the empty flat (or anti-de-Sitter) spacetime while S^2 times D^2 is the anti-de-Sitter Schwarzschild topology.

While the empty spacetime can be foliated, the S^2 times D^2 cannot because it has no S^1 factor, roughly speaking. Because it can't be foliated, you can't even define what the conservation of the information should mean in this topologically non-trivial case. The contribution to the correlators coming from the topologically trivial case are conserved as the Lorentzian time T grows; the contributions from the topologically non-trivial backgrounds decay.

On page 3, Hawking confirms that he was inspired by Maldacena's hep-th/0106112 about the eternal black holes in anti de Sitter space. In that case, you also have two - actually three - geometries that fit into the S^1 times S^2 boundary: empty space, small black holes, large black holes (compared to the radius of curvature). The large black holes dominate the ensemble; they have a large negative action. Nevertheless, using the bulk techniques you may calculate that a correlator of O(x)O(y) on the boundary decays for large separations (while it has the usual flat-space behavior if x,y are nearby).

Such a decrease looks much like other cases of information loss; nevertheless in this case you may argue that there is a unitary CFT behind it and the exponential decrease may be in principle reduced to repeated scattering. Maldacena also showed that the contribution of the empty spacetime does not decay and it has the right magnitude to be consistent with unitarity; Hawking argues that he strengthened this observation by having showed that the path integral over topologically trivial spacetimes only is unitary. (Again, it is not obvious whether his formal argument holds in reality because of the usual loop UV problems of general relativity.)

The large black holes are not too interesting because they don't evaporate. Instead, we want to look at the small black holes. Hawking has been trying to find a Euclidean geometry corresponding to an evaporating Lorentzian black hole for years. Now he says that he failed because there is no such geometry. In the Euclidean setup, only the metrics that can be foliated - empty space and eternal black holes - should be added to the path integral.

One of the main question that you must certainly ask is: Why does dynamics over topologically trivial spacetime look like the creation of a long-lived black hole with horizons in the Lorentzian signature? I believe that Hawking does not fully answer this question; he only says that "thermal fluctuations may occasionally be large enough to cause a gravitational collapse that creates a small black hole". Let me re-iterate that such a short comment is deeply unsatisfactory. What we want to understand in the first place is the bulk description of the process in which we can see that the usual long-lived black hole is there; we want to see how are the concepts of locality and causality corrected so that the information can escape.

Hawking only says that this solution of the information loss puzzle is possible. We could have said the same thing just because there is a dual unitary CFT description. But the local bulk dynamical mechanisms that make these things possible remain nearly as cloudy as before.

Some of Hawking's conclusions say:

• There are no baby universes branching off - which is what Hawking used to think. The information is preserved purely in our Universe.
  
• The black hole can form while remaining topological trivial because its evaporation may be viewed as a tunnelling process (Hartle-Hawking). Although this comment can't be considered to be a quantitative answer to my main question, I like it, and let me describe an analogy.

Imagine quantum mechanics of a particle on a line. The classically inaccessible regions (E smaller than V) may be compared to the black hole interior. Classically, these are qualitatively different regions from the rest. However, quantum mechanically, the qualitative difference disappears because of tunnelling. All points on the line are qualitatively on equal footing. You can get there. This is why the black hole should be thought of as having a trivial topology quantum mechanically. The situation would change for an infinite inaccessible region (infinite black hole) where you can't tunnel.

Let me summarize: Hawking's argument why the evolution is unitary probably works and The Reference Frame agrees with virtually all of Hawking's broader opinions, but such a solution is not much different from the observation that the dual CFT is unitary. The question why these unitary processes look like a small long-lived black hole and how the necessary correlations are created remains mostly unanswered.

Hawking has lost a bet but he seems to think that he has made the critical steps to solve the information loss puzzle. While he has given the encyclopedia of baseball to John Preskill, next time he will give him the ashes from a burned book (or the nearly thermal Hawking radiation) because John Preskill can always reconstruct the information out of them.