I have a long-percolating post that I hope to finish soon (when everything else is finished!) on “Why String Theory Must Be Right.” Not because it actually must be right, of course; it’s an hypothesis that will ultimately have to be tested against data. But there are very good reasons to think that something like string theory is going to be part of the ultimate understanding of quantum gravity, and it would be nice if more people knew what those reasons were.
Of course, it would be even nicer if those reasons were explained (to interested non-physicists as well as other physicists who are not specialists) by string theorists themselves. Unfortunately, they’re not. Most string theorists (not all, obviously; there are laudable exceptions) seem to not deem it worth their time to make much of an effort to explain why this theory with no empirical support whatsoever is nevertheless so promising. (Which it is.) Meanwhile, people who think that string theory has hit a dead end and should admit defeat — who are a tiny minority of those who are well-informed about the subject — are getting their message out with devastating effectiveness.
The latest manifestation of this trend is this video dialogue on Bloggingheads.tv, featuring science writers John Horgan and George Johnson. (Via Not Even Wrong.) Horgan is explicitly anti-string theory, while Johnson is more willing to admit that it might be worthwhile, and he’s not really qualified to pass judgment. But you’ll hear things like “string theory is just not a serious enterprise,” and see it compared to pseudoscience, postmodernism, and theology. (Pick the boogeyman of your choice!)
One of their pieces of evidence for the decline of string theory is a recent public debate between Brian Greene and Lawrence Krauss about the status of string theory. They seemed to take the very existence of such a debate as evidence that string theory isn’t really science any more — as if serious scientific subjects were never to be debated in public. Peter Woit agrees that “things are not looking good for a physical theory when there start being public debates on the subject”; indeed, I’m just about ready to give up on evolution for just that reason.
In their rush to find evidence for the conclusion they want to reach, everyone seems to be ignoring the fact that having public debates is actually a good thing, whatever the state of health of a particular field might be. The existence of a public debate isn’t evidence that a field is in trouble; it’s evidence that there is an unresolved scientific question about which many people are interested, which is wonderful. Science writers, of all people, should understand this. It’s not our job as researchers to hide away from the rest of the world until we’re absolutely sure that we’ve figured it all out, and only then share what we’ve learned; science is a process, and it needn’t be an especially esoteric one. There’s nothing illegitimate or unsavory about allowing the hoi-polloi the occasional glimpse at how the sausage is made.
What is illegitimate is when the view thereby provided is highly distorted. I’ve long supported the rights of stringy skeptics to get their arguments out to a wide audience, even if I don’t agree with them myself. The correct response on the part of those of us who appreciate the promise of string theory is to come back with our (vastly superior, of course) counter-arguments. The free market of ideas, I’m sure you’ve heard it all before.
Come on, string theorists! Make some effort to explain to everyone why this set of lofty speculations is as promising as you know it to be. It won’t hurt too much, really.
Update: Just to clarify the background of the above-mentioned debate. The original idea did not come from Brian or Lawrence; it was organized (they’ve told me) by the Smithsonian to generate interest and excitement for the adventure of particle physics, especially in the DC area, and they agreed to participate to help achieve this laudable purpose. The fact, as mentioned on Bloggingheads, that the participants were joking and enjoying themselves is evidence that they are friends who respect each other and understand that they are ultimately on the same side; not evidence that string theory itself is a joke.
It would be a shame if leading scientists were discouraged from participating in such events out of fear that discussing controversies in public gave people the wrong impression about the health of their field.
Eric,
Intriguing stuff but I still think there is a bit of an issue. Given the vast variety of string constructions, I don’t doubt that there is one that contains the MSSM at low energies with all of the couplings consistent with current measurements. But one expects that there will actually be many such string models which look roughly the same at low energy(since renormalization group isn’t actually a group and so isn’t uniquely invertible). Now, any given model which is consistent with SM will give unique predictions for higher energy physics. But let’s say you have one and it’s gets proven wrong by future experiments. “No big deal,” you say and move onto a slightly different model so string theory still lives. This is the feature that many people object to. That string theory won’t be falsified by the falsification of some model and doesn’t seem to give any unique predictions. The converse also seems to be true. If your model stands up to scrutiny in the next round of experiments, I’m not sure this gives much in the way of evidence for string theory, just for some effective field theory like the MSSM. To get real direct evidence for string theory, I think you probably need some data from the Planck scale, where string theory is qualitatively different from quantum field theory.
On the other hand, I think there are many channels of indirect evidence for string theory. Experimentally, finding low-energy SUSY at LHC will give a big boost of confidence that we’re on track with this set of ideas. Theoretically, things like black hole microstate counting, including higher derivative stringy corrections give (me, at least) confidence that the string program is on to something.
I don’t mean to deride your work, I think the sort of model-building you describe is important. But it seems to me mostly a “proof of concept”, like most, if not all, work in string theory.
Two things: First, I think Sean is right when he says often those manifestly opposed to string theory are those “who are a tiny minority of those who are well-informed about the subject.” It seems most anti-string theory people I meet have never taken formal courses on the matter. They form their opinions based off the opinions of others.
I don’t think it would be fair for me to judge until I have taken some formal courses so as I can judge for myself. (Only a couple of years more! 🙂 ) Then I will be in a better position to have a credible opinion.
Second: It seems the more I study high energy theory the more you have to evoke whatever works. You say “well, we get this infinity so we will just do this, and, oh look we get the right answer.” It seems sometimes we just play the game of finding the math that works best. If it turns out you have to call on higher dimensions and unseen fields and so forth to get the math to work out maybe that should be okay.
But again, I am no expert yet so I’m just throwing stuff out there. I am just grateful to be going into a high energy area and exploring these effects on the Universe. Keep the debate live and well.
Like Aaron, I’ll just suffice with self-promotion and refer back to my no-go theorem for string theory.
For a presumably well-informed opinion about string theory, consider what the founder of the string theory group at Rutgers write in subsection 1.6 of hep-th/0204131.
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The only blog thats even attempted to pose the question scientifically is Professor Distlers excellent series on motivation for quantum gravity (sorry dont have the link handy).
The simple arguments contained therein are more or less the prime reason people take it seriously. Namely quantum field theory doesn’t leave us many options for a consistent logical framework, and it seems the only way out leads straight smack into string theory (whether you are looking for it or not).
If string theory is wrong it nearly (but not quite) implies a massive inconsistency in the fundamental theorems of either special relativity, general relativity or quantum mechanics, and the possibiliities for an escape shrinks to an almost intractable level.
Naturally theorists took the easy way out of that problem and assumed thats not the case, rather than tackling the much harder problem of making sense of the inconsistency given that we know those three key aspects of the physical world make good sense in just about every experiment ever conducted.
“If string theory is wrong it nearly (but not quite) implies a massive inconsistency in the fundamental theorems of either special relativity, general relativity or quantum mechanics, and the possibiliities for an escape shrinks to an almost intractable level.” -Haelfix.
Jacques Distler’s defence of string theory ends with the following comment about LQG:
“Urs is right that LQG isn’t, strictly, a discretized model, though the use of the spin-network basis does introduce a fundamental length scale into the theory. It’s, more properly, a continuum theory, quantized in a Hamiltonian framework (albeit, a very, very unconventional one). The words I wrote above were geared to a Lagrangian formalism. It’s not hard to adapt them to a Hamiltonian one.” – Dr Distler’s Musings blog
LQG isn’t complete, so this sort of dismissal is unhelpful. LQG is far more economic than string theory. It introduces questions about special relativity on the quantum scale, hence “doubly special relativity”. Because there is a fundamental grain size in LQG, the Lorentz contraction can’t make that smaller due to motion, so the grain size is a fixed size irrespective of motion. This limits the scale of application of special relativity.
Maybe you think string theory is right because there are no alternatives and string is consistent with special relativity, etc? M-theory is claimed to be a self-consistent theory of quantum gravity. However, self-consistency in a totally speculative framework isn’t so stringent: what counts is consistency with facts.
The immense number of speculative, uncheckable assumptions involved in string theory: gravitons, 6/7 extra dimensions, supersymmetric partners for all observable particles, Planck scale unification, branes, etc., make it clear that it is not consistent with what is known. Ockham’s razor tells you that LQG is closer to reality. The path integral in LQG is the sum of all interaction graphs in the Penrose spin network. The result of this gives Einstein’s field equation. It’s not really a continuum, because each interaction graph is a quantum interaction. So Dr Distler is being misleading.
Much as I admire the fine physicists who collaborate to produce this blog, it seems to me that Sean unjustifiably and unfairly caricatures Peter Woit’s position when he flippantly claims:
“Peter Woit agrees that `things are not looking good for a physical theory when there start being public debates on the subject’; indeed, I’m just about ready to give up on evolution for just that reason.”
To put it bluntly, this verges on deliberate deception because Woit’s statement is taken so far out of context. What Peter Woit is clearly saying is that that “Things are not looking good for a physical theory when there start being public debates on the subject between recognized credentialed scientists about whether the theory even qualifies as either scientific or a theory.
As you can see, this completely blows Sean’s grossly distortive quip that “indeed, I’m just about ready to give up on evolution for just that reason” out of the water.
There is NO debate among serious credentialed scientists about whether the theory of evolution qualifies as either scientific or a theory. None. Zero. Zilch. Nada. Zip. Diddly.
What we get in regards to the theory of evoluiton is a bunch of phoney staged pseudo-controversies in which people with no qualifications and no credentials and no expertise in biology, people without degrees in biology, people without PhDs in biology, people who have never published any papers on evolution in recognized peer-reviewed professional academic journals, stand up and make long-debunked claims which the biologists who have published countless articles in peer-reviewed professional academic journals then shoot down in a few seconds. The biologists typically respond to these kinds of canards by remarking, “This is the fallacy of the second law of thermodynamics, which reflects a misunderstanding of the definition of a closed system and was original raised in [year X] and was definitively rebutted in [year Y].”
This is the same kind of pseudo-controversy you get when a flying saucer cultist stands up and makes wild claims, and skeptics debunk them by pointing to Project Blue Book and citing case after case after case where previous claims for the existence of flying saucers turned out to be hoaxes or lenticular clouds or lens caustics in cheap cameras.
Let’s be clear. That’s not a “debate.” It’s one kook spouting gibberish, and a scientist debunking it.
That’s no debate. An actual debate occurs when person X stands up and provide facts and logic to support his claim, and then person Y rebuts those facts and logic and provides facts and logic for hi/r own contrary assertion.
String theorists have no facts to support their assertion that string theory is science. They don’t have a single experimental result to support their contention that string theory is either scientific or a theory.
Consequently, all string theory “debates” (so-called) twixt serious scientists thus far have taken the following form: skeptical scientist A points out that a theory isn’t scientific and isn’t a theory if it can’t make any testable predictions and if no testable predictions have been adduced to support it. Credulous scientist B, a string theory supporter, indulges in hand-waving and blows a lot of smoke up everyone’s hoo-ha to disguise the fact that s/he cannot provide even one (1) testable predictions from string theory, and cannot provide even one (1) piece of experimental data published in the peer-reviewed professional physics literature to support the assertion that string theory is either scientific or a theory.
You tell me. Is that a debate?
No, that’s one scientist demanding that the so-called “theory” make predicitons and that experimental physicists provide evidence to back those predictions up. Then another guy waves his hands in the air and tries to distract attention from the hard cold provable fact that there are no testable predictions and there is no hard scientific evidence for string theory. None whatsoever.
To see how badly distorted and how fundamentally deceptive Sean’s false analogy with evolution is, let’s compare evolution with string theory:
If any scientist like Woit or Smolin demands hard experimental evidence for string theory, the string theorists provide nothing but hand-waving.
By contrast, if any scientist _were_ to demand that evolutionists provide testable predictions (no reputable scientist does, because evolution is so well-established and backed up by so much evidence the very question would be foolish), the evolutionists could deluge ’em with testable predictions. Let’s just run through 10 testable evolutionary predictions off the top of my head — first, evolution would predict that vaccines would gradually become ineffective as viruses and bacteria mutate over time. We have tested this prediction and it has proven irrefutably true. Second, evolution predicts that mammalian males will be generally larger than females because of selective pressure for males to battle other males over mates. Once again, this prediction has been extensively tested and has proven true. Third, evolution predicts that we’ll get the ratios Gregor Mendel found in his plant breeding experiments. This prediction has been tested and has proven true. Fourth, evolution predicts intermediate stages in the fossil records. While a few gaps exist, we have so many examples (such as Archaeopteryx) that this prediction has also proven true. Fifth, evolution predicts that developed characteristics cannot be inherited — i.e., Lamarckism isn’t correct and the children of people who exercise and build up their muscles are not born with larger muscles. This prediction has been tested and has been found true. Sixth, evolution predicts that because of the problems caused by inbreeding in humans, selective pressures will tend to favor the differentially greater reproduction of individuals with an innate aversion to incest. This prediction has been tested and has been found to be true in interesting studies which show that unrelated children raised together are not sexually attracted to one another, while related children raised apart can and sometimes do become sexually attracted to one another. Seventh, evolution predicts a common ancestor for all current forms of life. This prediction has been tested with DNA sequencing, most spectacularly with mitochondrial RNA sequencing, and has been proven true. Eighth, evolution predicts vestigial organs (Dollo’s Law). Once again this prediction has been tested and found true. Ninth, evolution predicts anatomical and molecular parahomology. This has been tested and found true by both paeloanatomists and by molecular biologists. Tenth, evolution predicts statistical support for phylogenies. The stats have been run on many different cases, and in each case cladistic analysis supports virtually completely and almost perfectly the known phylogeny.
To hammer this point home and demonstrate the thoroughly slipshod and inexcusably sophistical nature of Sean’s faulty analogy twixt string theory and evolution, there exist literally hundreds of websites which pile up mountains of evidence from the peer-reviewed scientific literature to support evolution as a scientific theory. Sites like
http://www.talkorigins.org/faqs/comdesc/
http://www.bartleby.com/65/ev/evolutio.html
http://www.txtwriter.com/backgrounders/Evolution/EVcontents.html
http://www.gate.net/~rwms/EvoEvidence.html
http://www.talkorigins.org/faqs/evolution-research.html
http://books.nap.edu/html/creationism/evidence.html
http://evolution.berkeley.edu/evolibrary/article/0_0_0/lines_01
http://www.evolutionpages.com/
Googling for the phrase “evidence for evolution” produces 1,130,000 pages containing that phrase. You could literally spend the rest of your life reading the gigantic mountain of evidence that has been published supporting predictions made by the theory of evolution, and you would still not reach the end of it.
Now let us compare with string theory.
Name me one peer-reviewed scientific journal, Sean, which has published a single experimental result predicted by string theory.
Name me one.
Just one.
You can’t. Because string theory makes no testable predictions.
Okay, Sean. Now show me the 1,300,000 websites contains peer-reviewed published evidence for string theory.
Show ’em to me, Sean. I want to see all those websites. Let me see ’em.
Whoops! There aren’t any.
Not ANY.
On the one hand, the theory of evolution, with more than a million pages citing peer-reviewed scientific literature chock full of evidence directly supporting it…
…And on the other hand, string theory — with not a single web page citing a single peer-reviewed piece of scientific literature directly supporting it.
Are they comparable?
You tell me, folks. Is Sean’s analogy valid, or is he being deliberately and flagrantly deceptive?
To compare the theory of evolution, which is supported by a vast Himalayan mountain range of evidence that vasts up so high that if you printed it all out, it would reach to the moon and well beyond, with the idle unsupported speculations of string theory which have not yet made a single testable prediction after 30+ years and for which not a single scrap of peer-reviewed published experimental evidence exists…it’s insulting.
Sean, there is little doubt that you are a lot smarter than I am. You’re almost certainly a lot smarter than 99% of the human race. But don’t piss on my leg, Sean, and tell me it’s raining.
I know the difference between a scientific theory for which a colossal pile of peer-reviewed experimental physical evidence exists, and a set of idle speculations which have never succeeded in making even a single testable prediction and for which not one single peer-reviewed journal article can be found adducing experimental evidence in support of those idle speculations.
Don’t insult my intelligence, Sean, by even _trying_ to compare string theory with the theory of evolution. Just as there is NO debate among ANY members of the serious scientific community about whether Darwin’s theory of macorevolution constitutes a scientific and testable and thoroughly-supported theory, there is NO debate among ANY members of the serious scientific community that there current exists not a single currently testable prediction made by string theory.
Even string theorists admit that they have no testable predictions. Lubos et al. resort to claiming that string theory’s prediction will become testable someday…or they resort to claiming that if we run enough stats on the cosmic background we might someday find circumstantial evidence which ambiguous relates to the landscape hypothesis. In short, even the string theorists themselves can only provide a vague hope that someday, somewhere, over the rainbow, enough stats or sufficiently novel tech might (somewhere, over the rainbow) provide some kind of ambiguous circumstantial evidence in favor of some part of string theory.
Guess what?
That’s not hard evidence. That’s a wish and a pipe dream. “Somewhere, over the rainbow.” Let’s give every string theorist the benefit of the doubt. Let’s assume they’re right. Someday, maybe we’ll get some kind of vague circumstantial evidence for some parts of string theory.
We don’t have it now.
Right now, we have nothing. And science isn’t about what somebody might find someday, somewhere over the rainbow. Science is about what we can find evidence for right here, right now. If we can’t find hard evidence for it, Occam’s Razor says throw it out. Hypotheses non fingo. Dump it. Junk it. Don’t need it. Phlogiston? Press the eject button. Luminiferous ether? Outa here. Vital animistic fluids? History. Theory of humours? Toast.
I’m sorry to say it, but even the deceptive and profoundly sophistical effort to _try_ to compare the massively-well-grounded theory of evolution (for which enormous amounts of scientific evidence exist) with a flimsy tissue of speculations and numerology like string theory is insulting. It’s an insult to my intelligence and it’s an insult to the intelligence of every thinking person reading this blog.
Look, I have nothing against string theory. Maybe it’s right. Maybe it isn’t. I don’t know. No one does. What string theory ISN’T right now is testable. Hand-waving about the landscape just makes the problem worse because as Woit and Smolin and any number of other folks with common sense point out, the landscape predicts everything you could ever possibly observe. Just plug in the fudge factors (AKA “parameters”) and voila! There you go. The universe we see around us.
That’s not a testable prediction. A theory that predicts everything you could possibly observe, as Woit and Smolin et al. have pointed out, actually predicts nothing.
To put it bluntly, the landscape is no different from the con job that phoney psychics sometimes try to pull on the Amazing Randi when they claim that their conjuring tricks no longer work because Randi’s skepticism interferes with the alleged delicate psychic energies involved in parapsychology. Catch-22 — as long as Randi is around being skeptical, the alleged parapsychological phenomena never seem to occur. Likewise, as long as we plug in the proper fudge factors into our landscape, we always get the universe we observe..but, unfortunately, since we can’t observe other universes, we can’t ever test the landscape hypothesis. What a wonderful Catch-22! As with the phoney psychic, the null hypothesis can never be tested.
Let’s turn Sean’s flippant and egregiously false analogy around. If Sean can practice the most outrageous kind of sophistry, so can we.
For Sean to compare the theory of evolution with string theory is like a ufologist claiming that astral projection disproves Einstein’s theory of general relativity because people who project themselves astrally travel faster than the speed of light.
That’s not a serious argument. Consequently Sean is not engaging in a genuine debate, he’s playing word games.
People who want to engage in a serious debate about string theory are going to have to bring more than deceptive and contemptibly casuistical verbal calesthenics to the table. They are going to have to bring testable predictions made by string theory, and experimental results published in the peer-reviewed physical literature to back up those testable string theory predictions.
Ball’s in your court, Sean. Let’s have ’em. Right now, on the table. Experimental results backing up testable predictions made by string theory. Show them to us right here, right now. Journal name, author(s), issue number, page numbers.
Josh,
The problem with string theory as a way to unify particle physics is not just at the electroweak breaking scale. It doesn’t predict anything at any scale up to the GUT scale, and only vague predictions even above that.
Eric,
Is your comment an April Fool’s joke? Honestly, I can’t tell. Seems to be hard to tell when string theorists are joking…
I suspect the Eric Mayes remark is in reference to a follow up paper to hep-th 0612087, but I could be wrong.
It would be nice if a skeptic (e.g. Woit), a neutral person and a strong advocate write a big article together, similar to this article about the number of dimensionful constants
John Horgan said: “Sean, jump off the sinking ship while you still can! ”
I don’t get it. John Horgan does not claim that the ship is sinking but rather that the whole ocean (of science) is drying.
(Is the Horgan’s suggestion for scientists is to go work on wall-street? 🙂 )
Eric Mayes (22): You might have forgotten that Cosmic Variance is on Central time, so you’re post appeared a few minutes before it was officially April 1.
mclaren (32): If you brush up on your reading comprehension, you’ll notice that I never compared the evidence for evolution with the evidence for string theory, about which you rant at such length. So your intelligence is somewhat self-insulting.
Eric,
if hep-th/0703280 is the paper you refer to, then it seems that there is a little bit of work left (perhaps as homework assignment for the reader).
E.g. on p.4 we learn that the electron mass comes out 6.5 times larger than it should be and the muon is 40% lighter.
But it seems that another paper is coming, which will fix this.
By the way, I thought that Volker Braun et al. already derived the MSSM from heterotic string theory some time ago, so there seems to be more than one way to do this.
Josh wrote
So far (Eric’s paper, which I haven’t read, aside), there aren’t any. Finding one would be significant progress.
Now, it’s true that, if you find one, you may be able to find others.
In orientifold flux compactifications, the visible gauge and its matter content are localized on some brane(s) at some singularity of the CY. Varying the fluxes elsewhere on the CY wll change the cosmological constant. But the properties of the SM couplings will relatively insensitive to changes made elsewhere on the CY.
It is far from clear that you will be able to “tune all of the knobs” (corresponding to the 100+ couplings of the MSSM) independently. I rather doubt that you will. Every knob that “can’t be tuned independently” is a prediction, and there’s no more reason to believe that number is zero than there is to believe that all 100+ parameters are uniquely determined.
But the real point is that I (and everyone else who opines on this question) is, at this point, simply speculating. We just don’t know, and expressing our personal prejudices on how this will work out is not a scientific argument.
If only it were that easy …
If you discovered proton decay tomorrow, would that give evidence for GUTs? After all, proton decay (and any other particle physics effect you could ever hope to measure) is completely adequately described by an effective field theory.
It seems to me that, if you find a microscopic explanation for certain relations between couplings in the low energy effective theory (in the case of GUTs, for instance, sin^2 of the Weinberg angle), you don’t say “Oh, that’s not evidence for anything about short-distance physics. All we’re doing is learning about properties of some effective field theory.
Sean,
You contemptuously dis mcclaren’s reading ability, but somehow managed to miss his central points – that you willfully distorted Peter Woit’s statement, and that the status of evolution and string theory are hardly comparable. You are the one who made this comparison, so it’s disingenuous of you to blame it on mcclaren. Moreover, you made the comparison on the basis of a distortion of Peter Woit’s statement.
Jacques,
I agree that the sort of model-building that Eric brought up is important and I said so explicitly. It would indeed be progress to find a model with exactly the SM in it at low energy, with all couplings and phases right. And maybe it would give evidence for string theory if such a model made a very surprising prediction for some slightly higher energy phenomena which is then verified at LHC; especially if this prediction is very natural in a string/brane setup up but not expected from field theory reasoning. Nature may surprise us and maybe it won’t.
You are right that we are speculating here, but I don’t see that as bad or necessarily unscientific as long as we recognize what we’re engaged in.
You have a good point in your analogy with proton decay and EFT. My only real point regarding EFT was that what we would really like to see is evidence of physics which can’t be captured by quantum field theory but is found in string theory. I could be wrong, but it seems like this would require near Planck scale experiments.
Peter,
I was just using the electroweak scale as an example since this is basically the region we are probing currently. I agree that there doesn’t seem to be specific, unique predictions at even much higher energies. My point was just that the motivation for string theory is really anchored in its candidacy as a theory of quantum gravity, and so I don’t expect it will be properly tested until we can test that regime somehow. If we also learn about particle physics that would be icing on the cake, but string theory’s fortunes do not rise and fall based on its implications for particle physics. Just my view though.
Gina asked:
Is the Horgan’s suggestion for scientists is to go work on wall-street?
If they ever get the LHC working and furter findings of nothing particularly interesting are further confirmed, then there will be a very long line of PhDs at ‘the Wallstreet employment office’, becauses stubborn pride will pretty much kill the whole field before it can be rebuilt from WAY BACK when they first started *believing* that ad hoc and theoretically flawed assumptions are proven facts… 😉
“The End of Particle Theory” JoAnne Hewett sets the Date
Horganism and John Baez
Except, CIP, that I did not distort anybody’s statement; the bit about “debates among credentialed scientists” was an interpolation on mclaren’s part, not part of what Peter or John originally said. If either of them would like to clarify, they are welcome to do so; it wouldn’t change the truth-value of what they are saying, but it would render the evolution example inapplicable.
I never compared the status of evolution and string theory, because that would be silly; the cases are not remotely comparable. What I did was to point out that the existence of public debates about a subject says nothing whatsoever about the status of that subject among people who are familiar with the details; evolution is the most obvious example.
The truth is, there is a long and honorable history of public debates about legitimate scientific questions between respectable scientists, and I think that’s a good thing.
Sean: You are going to get into the same very tedious loops that frustrated
Clifford on Asymptotia. One very trivial and peripheral comment of yours mentioning evolution generates a “War and Peace” length irrelevant rant.
The Horgan/Johnson dialogue is almost content-free. And, from what I have seen, arguing with Peter is like trying to hold quicksilver.
Peter,
As you are aware, I did misunderstand (4) your position from what was presented. Having now caught up with the comments, (39 as I write), I see that I am not unique in that.
It appears to me that there are actually multiple issues at play here which make miscommunication inevitable. On one level is the issue of whether string theory is is right or not, and on another level is the issue of whether string theory is even a scientific theory, since it cannot yet be tested. I interpret your statement:
…as reference to the position mclaren takes in (32):
It seems inevitable that the grow of our scientific foundation will lead to theories that exceed the testable reach of current instrumentation. I don’t view that as a bad thing, though I understand it may be decidedly uncomfortable to see the clear line between science and philosophy tested on both sides, (e.g. string theory as scientific philosophy and ID as philosophy pitched as science).
But there appears to be a third aspect of this discussion which elevates the tension for both issues mentioned at the top, (string theory’s veracity and whether or not it is even a scientific theory). That issue is how the scientific profession identifies winners.
In business and political blogs the participants often claim to want people who are willing to think creatively and take risks. But “risk” inherently means there are more losers than winners, so the question becomes “what happens to risk takers who lose?”
In poker losing the pot will get you invited back. In the science profession, if you bet the pot and lose, your career is typically taken out back and shot.
So public debate of unproven theory is risky, and dangerous to ones career. But is that good for science (and scientists)? Wouldn’t we all be better off by encouraging debate, and the attendant creative thinking, while reducing risk to the participant’s career?
Sean,
Ouch! Mea culpa. My apologies.
I looked, and you are right. I trusted mcclaren’s version of the quote and it’s not what Peter has up and it’s not what Horgan & Johnson said.
Never mind.
I will shut up now.
Josh wrote:
Absolutely!
As long as we’re clear about what’s speculation, and what’s established, this is a very useful conversation to have. The problem arises when people (not you) put forward their speculations and personal prejudices as established facts.
Unless we get extremely lucky (large extra dimensions), some effective field theory description is likely to be valid up to very high energies. So, yes, direct observation of non-field-theoretic (“stringy”) behaviour is rather too much to hope for. There are people thinking hard about indirect manifestations of non-field-theoretic behaviour — in cosmology, for instance — so, even there, it is possible that we may get by without a Planckian accelerator.
CIP, no problem.
“Pushed” (on both sides) would have been a better choice of word than “tested”…particularly in a science forum 🙂
Would it be accurate to say that the arguments in favor of string theory all boil down to the following?
(A) It has passed various consistency checks that could potentially have doomed it
(B) Every other proposed theory of quantum gravity suffers from more serious (arguably fatal) problems
That’s how it seems from this (non-high energy) physics student’s perspective. Based on (B) I can understand why a person studying quantum gravity would choose string theory over an alternative. What I don’t understand is why string theorists seem so convinced that the theory is correct. Should we be very surprised if string theory turns out to be both self-consistent and wrong? Or if the correct theory happens to be one we’ve never thought of?
I guess what I’m asking is: Why do string theorists seem so certain that this is the only possible answer? (Or am I overestimating their sense of certainty based on message board rhetoric?)