String theory's founding fathers have been a heroic group of solitaires who were developing a remarkable theory whose X Factor only became self-evident to most of the competent theoretical high-energy physicists in the mid 1980s. At that time, during the First Superstring Revolution, string theory became a mainstream subject, the generally appreciated "only game in town" when it comes to the unification of gravity with the rest of fundamental physics.
A subject that becomes mainstream enters the same risk as a stable corporation that has already grown big: It absorbs too many people that are too ordinary, too opportunist, and too unaware of the reasons why they're in that subject and not another subject. It has too many "followers" which may also be a ticket to stagnation.
As a guy who came to string theory from an unfriendly environment – the post-communist Academia which was mostly hostile towards string theory because its own scientific results were basically zero, much like the scientific contributions of the critics of string theory elsewhere – I always felt the gap between the "real people" who know what they're doing and the "other people". And I had the worrying feeling that the younger generation contains way too many "other people", too many "followers". The "real people" among the younger generations have been dangerously rare for decades.
Clifford Johnson praises an article by Frank Close on the testability wars in the Prospect Magazine. Close tries to be more impartial than other inkspillers who love to write about this non-topic but it's still a redundant article.
I've proven that the authors of similar "testability" sermons are worthless piles of pseudointellectual crap many times and I won't do it again. Everyone who hasn't understood the emptiness of that religion is one of its "believers". What I find new and worse is the rather lame would-be defense by Clifford Johnson. Here are his "three key points":
(1) Many important ideas in physics started out as purely mathematical digressions inspired by physics… You can’t find those ideas and make them work without exploring where they lead for a while, perhaps long before you even know how to test them. So we need that component of physics research as much as we need some of the other aspects, like designing and performing new experiments, etc.It's true that the character of some theories gets transformed as time goes by but this insight has no relevance for the "string wars" because string theory did not start as a purely mathematical digression and it was not a purely mathematical digression at any point of its history. String theory started as an extremely specific technical attempt to explain some features of extremely tangible experimental observations of the properties and collisions of hadrons.
It was a new paradigm to describe a set of totally empirical facts about a discipline in physics. Some of its predictions were nontrivially right for that purpose, others were wrong, and within a few years, a less revolutionary competitor – QCD – emerged as an explanation of the hadrons. All the string theorists understood that. In 1974, they also noticed that string theory was actually a consistent theory of quantum gravity (plus other forces and particle species). It had the technical properties needed to account for the empirical facts associated with general relativity as well as those linked to quantum mechanics. Some aspects of quantum gravity are similar to those of the strong interaction, others are different. But what one gets from string theory always coincides with what one needs in quantum gravity.
If this insight hadn't been made, string theory should have disappeared from the list of topics studied by physicists. But it was made, quantum gravity had been a puzzle for theorists par excellence for a few decades, and that string success had been the reason why physicists had and have a reason to investigate it.
(2) You never know where a good idea will ultimately find its applications… It is often not where we think it might be initially.Again, it's true but the relevance of this ignorance for our evaluation of the scientific theories – string theory, its competitors, and all other theories in all scientific disciplines – is zero. Or it should be zero. If we don't know something, we can't use this something to make conclusions! In particular, it is not legitimate for a scientist to judge research directions according to promises.
If an idea, a theory etc. seems uninteresting, unsuccessful, or useless and you believe that it will actually be interesting, successful, or useful, it is up to you to develop the idea or the theory to a form that may be recognized as a sufficiently interesting, successful, or useful one. You may work on that idea or theory at home – like giants of science a few centuries ago. But if you simply don't get to the point where an impartial competent observer may see that there's something interesting, successful, or useful about the idea, your opinion about the virtues of the idea or theory is just faith, and such faith shouldn't play any role in science, much like promises that are not backed by anything.
String theory is considered the most profound theory in contemporary fundamental physics exactly because it's the only one (beyond local quantum field theories) that has delivered something else than just faith and promises.
(3) Of course, testability (confronting an idea with experiment/observation) is key to the enterprise of doing science, there is no doubt in my mind. I do not think we need to start considering whether testability is something we can abandon or not. That’s clearly silly. We just need to be careful about rushing in to declare something testable or not testable before it has had a chance to develop into something useful. Unfortunately, everyone has a different take on just when it is time to make that declaration… and that’s what causes all the shouting and political arguments that generate a lot of heat and precious little light.I agree that the debates about abandoning testability are silly. All string theorists are only interested in the theory because it actually says something physically nontrivial about Nature – something that is in principle testable.
But I completely disagree with Johnson's "Unfortunately, everyone has a different take on just when it is time". Sorry, I don't have any take on that idea of "deadlines". Instead, I realize that everyone who believes in such an idea of "deadlines" is completely deluded, whatever his precise "dates" are.
A textbook example of these morons is Lee Sm*lin, a babbler who once suggested a five-year plan, like those of Yosip St*lin, in which a theory of everything has to be completed. This is totally silly because no one can know how much time it takes to develop a new paradigm in physics, what will happen in 5 or 20 or 50 years, or how big a currently unknown body of knowledge is going to be in the distant future.
You can't fix Sm*lin's childish criterion by changing the timescale. If you replace 5 years by 4 years, you will be more nationalist – the main difference between St*lin and H*tler was that the former had 5-year plans while the latter had 4-year plans – but the logical, qualitative reasons why this argument is completely irrational will be unchanged.
A sensible physicist – and a sane scientist or person – evaluates theories or "research programs" according to the evidence that is already available at this very moment. Speculations and promises about the future just cannot count! String theory is the only candidate theory of quantum gravity systematically studied by competent physicists simply because it's the only theory with the required properties that is known to science as of 2015. This has nothing to do with its being 5 year old, 30 years old, or 47 years old.
We don't need to speculate about the moment when the Planckian physics will be experimentally tested. I have never believed that it would be tested in any foreseeable future and it is in no way needed for some questions to be scientific. What's important that we already know now that the questions that string theory addresses are testable in principle. There are various possible answers and it just turns out that the existing empirical evidence combined with careful calculations and reasoning is enough to say a lot about the laws of physics because the things we already know, or can calculate, are extremely constraining.
The Asymptotia's comment section
In the comments, Moshe Rozali says that not even philosophers consider Popper's 1934 remarks as the final truth. He also says that string theory became understood to be "a method rather than a model". I don't agree with the sentence in this form. Like quantum field theory or even quantum mechanics in general, string theory is a theory or a theoretical framework. That means that there may be many "models" studied within this framework. But it is something else than saying that string theory is a "method".
String theory has taught us tons of methods and the only reason why we "clump them" is that all these methods are needed to study a particular physical theory, string theory. From a purely predictive viewpoint, string theory is a theoretical framework much like quantum field theory. There are different "versions" of string theory much like there are different "quantum field theories". One of them may be exactly right (quantum field theories in the spacetime may only be approximately right because they don't describe quantum gravity in its characteristic regime) and the other ones are its cousins.
However, if you're capable to look beyond superficial questions of predictivity, there's a big difference: different quantum field theories impose different laws of physics on Nature. But the different "versions" of string theory are actually solutions to the same laws of physics, same underlying equations. They are different vacua – different vacuum-like solutions or states – you may find within the same theory. String theory is primarily one theory. It is a very rich theory with lots of solutions and aspects but it is one theory, nevertheless.
To say that string theory is "one method" means to deny that there are hundreds of very different "methods" used to investigate string theory. And to say that string theory is "many methods" means to completely deny the reasons why these methods are being clumped into one group. The reason is that the methods are just servants to something much more important, namely the one unique theory unifying fundamental physics. Clifford Johnson:
Popular level articles tend not to care much about string theory as a powerful toolbox, presumably because they are aimed at audiences who have been bombarded only with discussions about theories of everything and the holy grail of physics, and the like….Sorry but there is a very good reason why string theory is presented as the holy grail of physics or a theory of everything rather than "a powerful toolbox". It's the string theory's status as the "holy grail of physics" or a "theory of everything" that really justifies the application of the "tools". Tools are great but they are not the final justification of what's being done. A toilet brush in a composer's villa may be a powerful tool but it's only a tool, not something primary, and that's why it's not being emphasized. The composer may also have a detergent in his house plus many other tools. Some of them are dirty, like some tools used in physics. But none of these tools is the point and none of these tools is the source of controversy, either.
If someone is just using some tools, like the toilet brush, then he is a worker, like a janitor in the composer's house. But not surprisingly, the sensible popular books are about the composer, not the janitor or his toilet brush. It's the musical compositions that justify (and pay for) the hiring of the janitor. The janitor's job doesn't justify the compositions.
Pragmatic discussions of what is calculable in various fields of physics and useful tools for doing so are just not as sexy.They're not only un-sexy. They're also genuinely secondary, less important. People interested in physics don't want to read about some boring technical stuff and they're right. They want to read about the big picture. It's also the big picture that determines – or should determine – which corners of the theories attract more "hard work with tools".
Unlike the would-be competitors, string theory allows the physicists to calculate lots of particular things. String theorists have a good idea what may be computed in principle (where we have a complete enough definition, for some purposes and levels of precision), what may be computed in practice, and what has actually been already computed by someone, but that still doesn't mean that they calculate everything that can be computed because it's not necessarily possible or important or interesting given the required hard work. And people are similarly interested in the "why" questions, the bosses, the justifications of the hard work, simply because those are primary. They mostly get completely wrong answers from the media and popular books these days but that doesn't mean that all of the questions they are asking are wrong. Well, some of the questions are wrong as well but questions whether string theory is the right theory of all interactions etc. is surely a very good and important question.
Clifford may find string theory's raison d’être unimportant and focus on some technical details of some "hard work with tools". But that doesn't mean that there are no organizing principles that determine "when it makes sense to use some tools or others".
Occasionally you do get the toolbox discussion, but then it is most couched as a separate issue on its own (the “shocking news – string theory may be useful for something!” Type articles….)….These titles (and majorities of the articles beneath them) are dramatically distorting the status and achievements of string theory. No person who is at least slightly informed about string theory would have any doubts that string theory is useful and important for tons of things. These titles and articles keep on repeating themselves partly because they're being tolerated by opportunist cowards who know better.
But Clifford offers something worse, the C-word ("consensus"):
And on point 1… I tend to look to practicing scientists as the ones who really, as a group, carve out what science really is and isn’t.Sorry, one can't define science as "whatever is being done by a group calling themselves the scientists". Lots of people – individuals or organized groups – may call themselves scientists but what they do is not science. These people's being numerous can't make their enterprise any better. I will avoid obvious examples from many corners of would-be science because every entry would make this paragraph more controversial than it should be. However, it is very important for a scientist to have non-sociological instincts about what science is and what it is not.
There are many exchanges between Clifford Johnson and Moshe Rozali. I would call them a waste of time. They're mostly politically correct clichés about the importance of communities for science etc., the kind of stuff that insults almost no one (except for people like me who find this PC stuff truly offensive). What's missing in their picture is the point that science is the ultimate meritocratic human activity.
To emphasize that his delusions about the consensus science weren't a typo, Clifford Johnson added:
I am curious though as to whether you [Moshe] have a historical precedent in mind for the “deep study of the subject” aspect. Can you point to a time where the physics community was all adrift and people from outside the community came and, after careful study, pointed the way?It depends whom you consider a person from "outside". They were rarely idiots but they were often not considered insiders. Most of the top 19th century fundamental physicists were obsessed with the aether. An outsider, a patent clerk named Albert Einstein, concluded there had to be no aether and he discovered rocksolid evidence – a new theory of spacetime.
The even deeper revolution, quantum mechanics, was ignited by folks like Werner Heisenberg. He barely got his PhD because he wasn't considered a good enough insider – a chap obsessed with all the details of experimental physics and interferometers and similar physics of his time. But he just knew everything he needed to know to build completely new foundations for all of physics. He focused on the "new physics" – ideas as new as relativity or newer – and that worked extremely well for him. It has worked great for many string theorists, too. (There are also lots of string theorists who were or are incredibly good researchers in the older physics, too.)
Heisenberg's groundbreaking discoveries were quickly understood (and elaborated upon) by a bunch of similarly competent physicists but my point is that they always had to evaluate the ideas according to their beef, not according to the author's being an insider or an outsider, if science was or is supposed to be systematically making progress.
The research of quantum gravity had existed for decades – and was done mainly by the "relativistic" community – but up to the early 1970s, it was completely wrong, meaningless, or content-free. The subject needed relative "outsiders" with a much better training in quantum mechanics and particle physics – such as Hawking and string theorists – to acquire beef. Well, I would actually start with Feynman who developed the Feynman rules for general relativity, including the first appearance of the Faddeev-Popov ghosts (for diffeomorphisms). That's perhaps when quantum gravity (in the broader sense) began as a quantitative discipline.
But Clifford Johnson is clearly a general celebrator of the "consensus science" and its track record. Even though there's some "medical bias" in it, Michael Crichton has provided us with the best list of the failing track record of "consensus science" (taken from the Aliens Cause Global Warming speech in 2003):
In addition, let me remind you that the track record of the consensus is nothing to be proud of. Let’s review a few cases.The people who claim that it's necessary for a field to be flooded by outsiders if it want to be on the right track are wrong. But so are the people who say that as long as there are insiders, things will be on the right track. None of these sociological recipes works. People doing some research, whether they are considered insiders or outsiders, simply have to do the work correctly, carefully, honestly. They have to learn about the relevant results by others and they have to systematically eliminate ideas that have been falsified.
In past centuries, the greatest killer of women was fever following childbirth. One woman in six died of this fever.
In 1795, Alexander Gordon of Aberdeen suggested that the fevers were infectious processes, and he was able to cure them. The consensus said no.
In 1843, Oliver Wendell Holmes claimed puerperal fever was contagious, and presented compelling evidence. The consensus said no.
In 1849, Semmelweiss demonstrated that sanitary techniques virtually eliminated puerperal fever in hospitals under his management. The consensus said he was a Jew, ignored him, and dismissed him from his post. There was in fact no agreement on puerperal fever until the start of the twentieth century. Thus the consensus took one hundred and twenty five years to arrive at the right conclusion despite the efforts of the prominent “skeptics” around the world, skeptics who were demeaned and ignored. And despite the constant ongoing deaths of women.
There is no shortage of other examples. In the 1920s in America, tens of thousands of people, mostly poor, were dying of a disease called pellagra. The consensus of scientists said it was infectious, and what was necessary was to find the “pellagra germ.” The US government asked a brilliant young investigator, Dr. Joseph Goldberger, to find the cause. Goldberger concluded that diet was the crucial factor. The consensus remained wedded to the germ theory.
Goldberger demonstrated that he could induce the disease through diet. He demonstrated that the disease was not infectious by injecting the blood of a pellagra patient into himself, and his assistant. They and other volunteers swabbed their noses with swabs from pellagra patients, and swallowed capsules containing scabs from pellagra rashes in what were called “Goldberger’s filth parties.” Nobody contracted pellagra.
The consensus continued to disagree with him. There was, in addition, a social factor-southern States disliked the idea of poor diet as the cause, because it meant that social reform was required. They continued to deny it until the 1920s. Result – despite a twentieth century epidemic, the consensus took years to see the light.
Probably every schoolchild notices that South America and Africa seem to fit together rather snugly, and Alfred Wegener proposed, in 1912, that the continents had in fact drifted apart. The consensus sneered at continental drift for fifty years. The theory was most vigorously denied by the great names of geology – until 1961, when it began to seem as if the sea floors were spreading. The result: it took the consensus fifty years to acknowledge what any schoolchild sees.
And shall we go on? The examples can be multiplied endlessly. Jenner and smallpox, Pasteur and germ theory. Saccharine, margarine, repressed memory, fiber and colon cancer, hormone replacement therapy. The list of consensus errors goes on and on.
Finally, I would remind you to notice where the claim of consensus is invoked. Consensus is invoked only in situations where the science is not solid enough.
Nobody says the consensus of scientists agrees that E=mc2. Nobody says the consensus is that the sun is 93 million miles away. It would never occur to anyone to speak that way.
They have to maintain standards and that's the best thing they can do for their field to avoid dead ends and wrong tracks. Musings about mysterious abilities of outsiders or insiders can't replace the tough, rational, mathematically solid, empirically rooted arguments that science demands.
Equally, particular superstring theories are obviously false, heterotic E8xE8 for example.Heterotic \(E_8\times E_8\) string (on Calabi-Yaus or closely related manifolds) remains the one of the most viable – if not the most viable – category of models to describe all interactions and matter in Nature. See some recent heterotic pheno papers.
Physicists are of course biased when it comes to judging their own theories. That is a priori not a problem. The problem is that they’re not educated to become aware of and account for their biases.A good scientist may be excited, overexcited, or underexcited about some ideas. Science actually has tons of examples in which the big discoverers underestimated the importance of their discoveries – Max Planck and his black-body curve derivation is a great example. Albert Einstein and the GR's prediction of a non-static Universe is another one. Great scientists are actually more likely to underestimate their theories than to overestimate them – but it's still a mistake one should avoid!
Better scientists are generally able to divide ideas to good ones and bad ones more accurately than worse scientists and non-scientists. And a good scientific community is able to divide scientists to good ones and bad ones! The meritocracy at these two levels is what is needed for the scientific progress. There will always be biased people and incompetent people. They're not a problem for the progress in science as long as they have not conquered science.
My pet peeve is that it’s extremely hard to change topics after PhD.A normal intelligent person has his formative years up to a certain age – and he learns the majority of the framework while young enough. What he learns later is usually "incremental" and what he does are mostly "applications". But in general, good enough people may learn very new things throughout their lives and they may achieve great things in them.
The actual reason why "some people find it hard to change topics after their PhD" is that they are not really good at anything, not even the topic of their PhD which they would like to abandon. But they realize that they're not treated seriously in other topics. Here, the most typical problem is that they are treated seriously when it comes to the topic of their PhD thesis even though this shouldn't be the case, either. The actual problem is that some (and probably many) PhDs are thrown away to wrong people.
But if you think that the specialization of your PhD thesis is the only barrier that prevents you from successfully working on other topics, well, maybe you should get the PhD in the new field, too! Individual people and institutions may err in individual examples – when they don't trust people talking about a subject in which they don't have a PhD (even though these non-holders of the degree may be right and very wise) – but there is also a very good reason why much of this work on "out of expertise" topics is being ignored: Most of it is a bad quality work or downright rubbish. Most people are just the laymen when it comes to different subjects. Even if they are self-confident, they wouldn't really get the PhDs from the other subjects. They honestly wouldn't deserve it. This is the reason why it's usually totally right that it's not trivial for generic people to "change their topics after their PhD". There don't seem to be reasons to think that they would be good at it and in most cases, they are actually not good at it.
And while I am here, let me also ask you a question. I have the vague impression that there are not so many people left working on string theory as ‘the theory of everything’ and instead most are now doing AdS/CFT and extensions thereof (dS, time-dependent, etc), dualities in general and applications. Do you share this impression?This comment is a mixture of truths that are unfortunate – while she is happy about them – as well as some untruths and deep misunderstandings. To mention an example of the latter, it's complete nonsense to suggest that the research into string/M-theoretical dualities is not a "research of string theory as a theory of everything". It is arguably the key part of the foundational, big-picture work on string theory. Dualities (and the foundational parts of the AdS/CFT research, too) are important for our understanding what string theory is; and they are crucial for a mapping and understanding of realistic vacua, too.
When it comes to the atmosphere in the broader public, I surely do share her impression, however. Opportunist cowards such as Clifford Johnson and, to a lesser extent, Moshe Rozali prefer good relationships with aggressive subpar scientists such as Sabine Hossenfelder. So in many cases, it's dishonest zeroes similar to hers who determine the discourse while the likes of Rozali and Johnson shut their mouth about the actual status of string theory, minimize their research into far-reaching aspects of the theory because they saw that there are people who are hostile towards it, and reduce themselves to the masters of the "toolbox" whose main purpose is not to offend anyone.
Every competent high-energy theoretical physicist knows that the evidence supports string theory's being a "theory of everything" at least as much as it did 20 or 30 years ago. But most of these people are unfortunately not courageous so most people never learn that the Internet and newspapers has been flooded by false demagogy produced by subpar pseudointellectuals such as Hossenfelder.
Clifford Johnson replied by a tirade basically against string theory's being a unifying theory of all interactions. Random posters mix random ideas from random preprints into this conceptual debate. At least Moshe Rozali writes something sensible about the complex operations that tests of a theory typically demand.
There are lots of points in these discussions, some of them are valid, most of them are invalid. But the overall impression – and the actual, at least apparent goal – of all these texts and debates is very clear, namely to put string theory on trial. A universally overlooked key point is that a person willing not to celebrate the mankind's most viable, deepest, most unifying description of Nature and to put it on trial instead is an uncultural savage, a wild animal that should be treated seriously by no decent and educated human being.
Unfortunately, this point is not being made even by folks like Moshe Rozali and especially Clifford Johnson. Similar guys contribute to the proliferation of anti-science demagogues pretending to be scientists, such as Sabine Hossenfelder. In the environment defined by the likes of Clifford Johnson, the likes of Hossenfelder have no natural enemies. What a surprise that their percentage is growing.