Point on the ‘simple and elegant’: that’s a deep issue right there, starting from Occam’s razor down to very modern ideas of Kolmogorov-Chaitin complexity, that I’ll talk about in my review of Gregory Chaitin’s “Meta Math: the search for omega,” a book whose bottom line is that ‘simple, elegant and predictable’ is the exception rather the rule if you believe that the continuum (as in 1 d time or 3d space) has any real meaning. You can either drop the idea of simple/elegant/predictable or drop your most basic sense of reality, the sense of “continuousness” that forms the fabric of our perception.

Most scientists today are Popper-ians, so they DON’T take the simple/elegant as an axiom, but merely an operational truth about anything they can usefully work on.

There are a few more subtleties here that I’ll think about and maybe tease out later.

Questions: Is the statement “The Universe is predictable / consistent enough to allow us to make testable predictions based on simple and elegant models” a belief / axiom that all science is based upon? Or can we say that this statement need not be believed for scientific pursuit? Can we drop the “based on simple and elegant models” part of the statement and still find satisfaction in trying to explain the Universe?

— Viraje

Many people are aware of the Weak and Strong Anthropic Principles. The Weak One says, basically, that it was jolly amazing of the universe to be constructed in such a way that humans could evolve to a point where they make a living in, for example, universities, while the Strong One says that, on the contrary, the whole point of the universe was that humans should not only work in universities but also write for huge sums books with words like “Cosmic” and “Chaos” in the titles.

…and the second from Vonnegut:
“Beware of the man who works hard to learn something, learns it, and
finds himself no wiser than before,” Bokonon tells us. “He is full of
murderous resentment of people who are ignorant without having come by
their ignorance the hard way.”

Thank you, I’ll shut up now

Quasi-teleological arguments always lend themselves to parody that way. Daniel Quinn’s Ishmael pokes at linear tellings of the Darwinian evolution story that end with “And then finally homo sapiens evolved” by having a starfish tell the story, which ends, “And then finally, the starfish evolved”

But its use in supporting string theory aside, the anthropic principle does have a certain appeal to it when applied to the multiple-universes scenario (the weaker version which argues that earth has life-supporting properties because we wouldn’t have evolved to remark about it otherwise, is uncontroversial I think).

However, I find the idea of a theory which can has enough knobs that you can tweak it to explain anything, but which does not make predictions which can be experimentally verified, to be dangerously close to theology.

If you really want something like that, why not go with “It’s God’s will…” For every possible question, you have a simple, unfalsifiable answer “It’s God’s will that the proton decayed to a beta carotene”. Explains everything, but tells you nothing. Saves you a lot of headaches trying to comprehend the math, at any rate.

The sociological critique reminds me of Pratchett’s “Special and Inevitable Anthropic Principle”, put forward by Unseen University’s Professor of Anthropics, which claims that the entire reason for the universe to exist was for the eventual evolution of the Professor of Anthropics.

I am just starting to explore the world of physics blogs as I cue up more interested-onlooker articles on physics. Pointers to other blogs besides Peter’s welcome!

Venkat

Again, one might argue that this sort of shoddy refereeing is quite a widespread problem and not specific to cosmology/quantum gravity/string theory. Remember the story of the computer science grad students who wrote a computer to randomly generate scientific-sounding papers and then got one such paper published in a journal? I quite agree with you that this is a serious problem, however, I personally don’t find that conduct of cosmologists/quantum graviters/string theorists differs significantly from the rest of physics. (There’s a lot more speculation, of course, as compared to something like condensed matter theory but that’s to be expected because those fields are inherently more speculative.) Some sring theorists have not taken the high road in responding to your criticisms and this is lamentable, however, I suspect you’d find the same thing if you had published a lengthy critique of any other research programme.

It’s worth being clear that I do appreciate your point of view and think that you do make some good points (though the stuff which surfaces frequently on your blog about string theory being a religious cult with Witten as head guru is, I think, a little silly). Differences of opinion in science are a good thing and this kind of controversy has a positive aspect to it. However, I do think that some of the criticisms being launched against string theory are misleading or unfair (of course many of the claims made by string theorists are overstated, but two wrongs don’t make a right). Anyway, I have enjoyed all this lively debate!

Thanks for the well-done review of my book and Lee Smolin’s. I think you give an accurate and reasonable take on what is in the books.

bog,

What’s in my book about the Bogdanovs and Harvard is just a direct quote from an e-mail sent by someone who was visiting there at the time. Undoubtedly a bit of an exaggeration, but if you look at Lubos Motl’s blog you can find an extensive defense of the claim that the Bogdanov papers are not nonsense. I don’t know this for a fact, but I’d suspect that one of the people the e-mail writer may have been observing was Motl (at the time a Junior Fellow, on his way to an assistant professorship). The referee reports are available, and at least one of them indicates that the referee read the paper since he/she gave a long list of things that needed to be changed to make the paper acceptable for publication (it was published after this rewriting to address the referee’s comments).

I don’t think the Bogdanov affair is specifically an indictment of string theory, but it is an indictment of quantum gravity/cosmology in general, a field which is now heavily dominated by string theory. At the time I initially wrote the chapter of the book about the Bogdanovs I had some qualms about whether I was making too strong a claim about how bad the situation was in this field. The increasingly large amount of absurdity being published as “string cosmology” and the behavior of people like Motl has convinced me over the past few years that the problem I pointed to in that chapter is a very real and increasingly serious one.

Have you actually looked at the Bogdanov papers? You don’t need to be a genius to tell that they’re rubbish, you just need to actually read them. I’m arguing that the referee didn’t even read them (this wouldn’t be shocking – it happens all the time). It’s almost inconceivable that any professor working in HEP theory couldn’t tell that they were nonsense (at Harvard or anywhere else) assuming that said professor ACTUALLY READ the papers. Since these papers were published in obscure journals (also not put in the arxiv) and written by unknown authors it seems to me very likely that nobody at all ever looked at them.

It’s probably true that many physicists don’t like to admit that they don’t know things but, again, I don’t see what this has to do with string theory. It’s worth mentioning that I’m not a string theorist. I just think that this line of attack is very misleading, in fact it’s probably a staw man. The criticism that is being made here applies quite generally to physics as a whole and I think it’s unfair to put all the blame on string theorists.

As for my anonymity, I’m preserving it for fear that Witten will have me “wacked”.

Bog, making personal statements about other people being liars and your own graduate students being brilliant is ineffectual if you retain anonymity, so why not tell us your name and bathe in the glory of your own making?

BTW, you’ve missed Woit’s point entirely:

‘The one thing the journals do provide which the preprint database does not is the peer-review process. The main thing the journals are selling is the fact that what they publish has supposedly been carefully vetted by experts. The Bogdanov story shows that, at least for papers in quantum gravity in some journals [including the U.K. Institute of Physics journal Classical and Quantum Gravity], this vetting is no longer worth much. … Why did referees in this case accept for publication such obviously incoherent nonsense? One reason is undoubtedly that many physicists do not willingly admit that they don’t understand things.’

- Woit, Not Even Wrong, Jonathan Cape, London, 2006, p. 223.

I personally submitted a paper to the editor of Classical and Quantum Gravity (a U.K. Institute of Physics journal) and it was refereed and returned to me by the editor with an anonymous referee’s report stating that it was since it was fact-based and made falsifiable predictions, it was incompatible with string theory speculations and should be censored out. There was no comment on my calculations and no fault found in them whatsoever. The entire reason for rejection was incompatibility with M-theory. So I can personally tell you, these bigoted stringers aren’t scientists, they don’t use science for any purpose whatsoever, in fact, they are all anti-science as Feynman explained:

‘Science is the organized skepticism in the reliability of expert opinion.’ – R. P. Feynman (quoted by Smolin, TTWP, 2006, p. 307).

Bog, you are partly right, Woit says the Bogdanov papers were actually about quantum algebra and topological quantum field theory, but also says, (page 216): “The discussion section at the end of their three identical papers is all about relations of their work to superstring theory and the problem of supersymmetry breaking” … later on the same page, he cites a referee report that begins “motivated by string theory results…” Without being a physicist myself, I guess I am guilty of not appreciating these finer distinctions.

Chris, thanks for the clarification. I personally found the philosophical argument for background independence quite alluring, but I understand it is not quite as compelling a critique as the lack of experimental evidence.

And to re-iterate, I am NOT a physicist, so thank you all for pointing out some of my errors. Am just launching into Penrose’s “Road to Reality” seriously, so I hope to improve the quality of my outsider-commentary on physics as I write more. I want to emphasize that the language in the review (“concludes that the lack of sound foundational concepts in the field has created a world full of technicians who can’t even understand each other’s dense calculations as garbage.”) is my paraphrase of the overall sentiment that I got from Woit’s writing, so any inaccuracy in representing his opinion are my fault and Woit probably meant to convey a more precise critique.

Rgds,

Venkat

It’s worth pointing out that the Bogdanov papers weren’t about string theory, so I’m not sure how this is a criticism of string theory. I, personally, find it extremely unlikely that this mess had anything to do with HEP theory being “full of technicians who can’t even understand each other’s dense calculations as garbage” and MUCH more to do with a couple of lazy, shoddy referees. I’ve had a wide rang of experiences with referees, some of them clearly gave the paper a cusory reading at best. I think that there is a lesson to be learned from this affair but it’s not about string theory, it’s about the serious flaws in the peer review process.

The anecdotes which Woit tells of prominent Harvard theorists being unable to tell if the papers were nonesense are, I suspect, exaggerations at best (perhaps even a flat out lie). I’m quite certain that any of my grad students could tell that those papers were nonesense.

String stuff makes me very angry because it’s declared to be the mainstream theory, when in fact it’s half baked speculation that can’t calculate anything solid and checkable; not a single falsifiable calculation has come from it. It’s not possible to ever calculate anything seeing that there are so many parameters in the theory whose values are arbitrarily adjustable and cannot be observed.

I think that Lee Smolin and Peter Woit are deliberately avoiding a confrontation with people like Edward Witten over the deeper issue that string theory is actually based on incorrect speculations that spin-2 attractive gravitons mediate gravity and that standard model forces unify at very high energy. There is experimental evidence against spin-2 attractive gravitons and against supersymmetric (or any other) unification at very high energy.

Gravity can be predicted accurately (within experimental error) from a quantum gravity model utilising spin-1 gravitons which push masses together. This makes accurate calculations of other phenomena too but was censored off arxiv in 2002. It puts gravity into the standard model very simply. This blows apart most of the requirements for string theory. String theorists ignore work such as this, or loudly oppose it without having first bothered to read it. They’re prejudiced in favor of the particular speculations they work on even though they have not a shred of objective evidence, and that’s very dangerous for them and harmful to others. Other theorists may have wrong ideas, but at least they can test them.

It is interesting that you call string theorists non-calculating. I got the impression that they are viewed as doing dense, incomprehensible mathematics that explore the mathematical structure of the mystery-theory without getting to falsifiable tests.

In my own field there is a relatively healthy mix of conceptualizers who love abstractions, pragmatic folks who have no patience for abstractions, “beauty” driven calculators and “data” driven calculators. I’ve never felt oppressed by one kind.

I think your review is good up to this ending. But the “shut up and calculate” philosophy is due to Feynman, and is the precisely criticism he had of string theory:

‘… I do feel strongly that this is nonsense! … I think all this superstring stuff is crazy and is in the wrong direction. … I don’t like it that they’re not calculating anything. I don’t like that they don’t check their ideas. I don’t like that for anything that disagrees with an experiment, they cook up an explanation … All these numbers [particle masses, etc.] … have no explanations in these string theories – absolutely none!’ – Richard P. Feynman, in Davies & Brown, ‘Superstrings’ 1988, at pages 194-195. (Quotation courtesy of Tony Smith.)

The problem with superstrings is that the 6 extra dimensions have to be postulated as rolled up and invisible, which prevents their 100 or so parameters (size and shape) being known. It’s impossible to experimentally find these parameters because the only way to reveal the exact structure of the Calabi-Yau manifold would be by Planck-scale scattering experiments in a particle accelerator the size of the galaxy. Without these 100 inputs to the theory being known, there are 10^500 possible outputs, and the theory is so vague it’s not falsifiable. That’s why it’s not science but deluded groupthing maintained by paranoia, arrogance, censorship and bigoted charlatanism towards genuine ‘alternatives’.

I don’t think there is anything wrong with calculating falsifiable predictions really, just with the kind of non-calculating, arm-waving, priestly, dictatorial, wishful-thinking approach to physics that many hotshot string theorists prefer.

Best wishes,
nigel