String Theory Gets Real – Not

A recent issue of Science magazine has an article about the “Strings and the Real World” workshop at Aspen this past summer, entitled String Theory Gets Real — Sort Of. A more accurate title for the article might be “String Theory Would Like to Get Real — But Can’t Because it Doesn’t Work”.

The article claims that up until recently string theorists were not even trying to connect string theory with experiment, but “Now a small but growing number of them are trying to forge connections between string theory and detailed data”. This is really nonsense. There have always been plenty of people doing “string phenomenology”, but it has always been a doomed subject, for reasons I’ve gone on about at length here and elsewhere. The article does mention the problem of the Landscape with the increasingly standard loony comment that “physicists may have to rethink what it means for a theory to explain experimental data”. This is absurd. There’s no question about what it means for a theory to explain experimental data and the simple fact of the matter is that this theory can’t do it.

There’s also a claim that “the cosmological constant now appears to be real, and string theorists hope to calculate its value”. This misunderstands the whole Landscape argument, which tries to justify why no one can ever hope to calculate this value.

The article also includes a sidebar which tries to explain why young people go into string theory. It quotes a Penn postdoc, Brent Nelson, as saying that he read about string theory as a teenager and couldn’t believe so many people accepted something so outlandish. But he went into string theory anyway, and now says “I haven’t learned enough… I still don’t know why I should believe”. Sorry Brent, but no matter how long and hard you stare at this particular emperor trying to appreciate the beauty of his clothing, he’s still going to be naked as a jaybird.

Finally, when asked how many revolutions will be needed to make string theory work, John Schwarz says “I don’t know, but I think we’ll need many more”. At about a decade per revolution, it looks like Schwarz now doesn’t expect to live to see this happen. Neither do I.

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10 Responses to String Theory Gets Real – Not

  1. D R Lunsford says:

    NYTimes article

    Iterates the usual fabrication that ST contains GR. 5 pages of MOTS.


  2. Lubos Motl says:

    “God that failed” – like the communist ideology – is a pretty good formulation that keeps the reader interested. It’s obvious that a good journalist would always ask this question in this way.

    However, if you open The Elegant Universe by Brian Greene, for example, you will see a lot of comparably elegant possible criticisms against string theory (Chapter 9). 😉 String theory is undermining science like medieval theology; string theorists should not be allowed to convert sensitive students into perverse deviants etc. 🙂

    Of course that these questions and strong words are said exactly because the answer that they suggest is probably not true, which is the truly exciting part of the story.

  3. Chris Oakley says:

    Is string theory the physics equivalent of The God That Failed, as some people used to say about communist ideology?

    It is interesting that Scientific American should ask a loaded question like this. Maybe the tide is finally turning, and not in favour of those who think we need to change the dictionary definition of science.

  4. Lubos Motl says:

    Concerning the interview with L. Krauss.

    I think that it is still an interview with a string theory layman. It’s great to say that string theory has not revealed the nature of dark matter, but on the other hand it is not the most straightforward question that string theorists should ask.

    Eventually, unless the MOND-like theories will turn out to be right, the dark matter will just be *something*, a new particle (like bino, a superpartner), and there won’t be too much to learn about other physics from this single piece of information.

    Krauss describes LQG and string theory almost on equal footing, which is of course ridiculous, but at least, he mentions the obvious fact that string theory has led to interesting mathematics, unlike loop quantum gravity.

    Is there someone here who believes that LQG has led to interesting mathematics?

  5. plato says:

    Maybe they didn’t understand the essence of the blackholes and the mathematical framework that was to go along side of the physics?:)

  6. Chris W. says:

    You know, Peter, I sense an increasing ennui spilling out into the popular science press, and a tinge of cynicism in the comments of journalists in spite of themselves. Another example occurs in this interview with Lawrence Krauss:

    SA: Is string theory the physics equivalent of The God That Failed, as some people used to say about communist ideology?

    LK: Not exactly. But I do think its time may be past. String theory and the other modish physical theory, loop quantum gravity, both stem from one basic idea: that there’s a mathematical problem with general relativity.
    The idea is that when you try to examine physical phenomena on ever smaller scales, gravity acts worse and worse. Eventually, you get infinities. And almost all research to find a quantum theory of gravity is trying to understand these infinities. What string theory and what loop quantum gravity do is go around this by not going smaller than a certain distance scale, because if you do, things will behave differently. Both these theories are based on the idea that you can’t go down to zero in a point particle, and that’s one way to get rid of mathematical infinities. The main difference, I think, between the two theories is that string is intellectually and mathematically far richer.
    String theory hasn’t accomplished a lot in terms of solving physical problems, but it’s produced a lot of interesting mathematical discoveries. That’s why it fascinates. Loop quantum gravity hasn’t even done that, at least in my mind.

    With respect to his comments on LQG, I’ll have to bite my tongue for the moment.

  7. Fabio Lanzoni says:

    Give the poor science writer a break- he was probably on deadline.

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