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Breaking: Article in Nature defends integrity of physics against multiverse, string theory

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“Scientific method: Defend the integrity of physics” by George Ellis and Joe Silk,” Nature, open access:

This year, debates in physics circles took a worrying turn. Faced with difficulties in applying fundamental theories to the observed Universe, some researchers called for a change in how theoretical physics is done. They began to argue — explicitly — that if a theory is sufficiently elegant and explanatory, it need not be tested experimentally, breaking with centuries of philosophical tradition of defining scientific knowledge as empirical. We disagree. As the philosopher of science Karl Popper argued: a theory must be falsifiable to be scientific.

Earlier this year, championing the multiverse and the many-worlds hypothesis, Carroll dismissed Popper’s falsifiability criterion as a “blunt instrument” (see go.nature.com/nuj39z). He offered two other requirements: a scientific theory should be “definite” and “empirical”. By definite, Carroll means that the theory says “something clear and unambiguous about how reality functions”. By empirical, he agrees with the customary definition that a theory should be judged a success or failure by its ability to explain the data.

He argues that inaccessible domains can have a “dramatic effect” in our cosmic back-yard, explaining why the cosmological constant is so small in the part we see. But in multiverse theory, that explanation could be given no matter what astronomers observe. All possible combinations of cosmological parameters would exist somewhere, and the theory has many variables that can be tweaked. Other theories, such as unimodular gravity, a modified version of Einstein’s general theory of relativity, can also explain why the cosmological constant is not huge.

Some people have devised forms of multiverse theory that are susceptible to tests: physicist Leonard Susskind’s version can be falsified if negative spatial curvature of the Universe is ever demonstrated. But such a finding would prove nothing about the many other versions. Fundamentally, the multiverse explanation relies on string theory, which is as yet unverified, and on speculative mechanisms for realizing different physics in different sister universes. It is not, in our opinion, robust, let alone testable.

No wonder some would like to abandon testability for elegance, and reality for fairy tales.

Unfortunately, the plea ends on a somewhat tinny note,

The imprimatur of science should be awarded only to a theory that is testable. Only then can we defend science from attack.

Guys, listen (yes, you George Ellis and you Joe Silk, it is you we are looking at): The problem really isn’t attacks from outside. Quit fooling yourselves.

The problem is entirely within. If physicists want to join the many and various advocates  of self-expression who do not depend on rigorous examination of evidence to validate their assertions, that is a choice physicists make.

No one forces that choice on physicists. But they are free to make it.

It sounds as though some of your colleagues have been making just such choices, and defending their choices by asking for exemption from traditional standards. It’s your profession’s call to determine whether their wishes/demands can be accommodated simply to prop up whatever rickety theoretical structures they have built.

But if your profession does choose to accommodate, two things:

1. Physics becomes just another player in a culture war, with no more genuinely respectable claims for attention than the demands we hear daily from grievance warriors that their version of events be accepted without cavil as Truth. You could find yourselves currying favour with politicians, as an identity group, for your version of nature versus that of magical thinking. Is that really what you want?

2. If so, just remember, no one did that to you. You did it to yourselves.

See also: The bill arrives for cosmology’s free lunch

Hat tip: Peter Woit

7 Replies to “Breaking: Article in Nature defends integrity of physics against multiverse, string theory

  1. 1
    bornagain77 says:

    “In so far as a scientific statement speaks about reality, it must be falsifiable; and in so far as it is not falsifiable, it does not speak about reality.”
    Karl Popper – The Two Fundamental Problems of the Theory of Knowledge (2014 edition), Routledge
    http://izquotes.com/quote/147518

  2. 2
    bornagain77 says:

    Of interest to theoretical mathematics that are fruitful to the progress of science, it is said that the best mathematical theories, that are later confirmed empirically to be true, were born out of the mathematician’s ‘sense of beauty’. Paul Dirac is said to have mathematically discovered the ‘anti-electron’, years before it was able to be empirically confirmed, through his mathematical ‘sense of beauty’:

    Graham Farmelo on Paul Dirac and Mathematical Beauty – video (28:12 minute mark – prediction of the ‘anti-electron’)
    https://www.youtube.com/watch?v=YfYon2WdR40

    In January 1933, the Belgian mathematician and Catholic priest Georges Lemaitre traveled with Albert Einstein to California for a series of seminars. After the Belgian detailed his Big Bang theory, Einstein stood up applauded, and said,

    “This is the most beautiful and satisfactory explanation of creation to which I have ever listened.”

    As well, Dyson considered Higg’s mathematical work to be ‘beautiful’:

    How the hunt for the Higgs boson began – Nov. 2010
    Excerpt: Higgs collected his papers and, step by step, took the audience through his theory. Dyson listened intently. He thought Higgs’s work was beautiful.
    http://io9.com/5682875/how-the.....oson-began

    ‘Mathematical beauty’ even had a guiding hand in the discovery of the Amplituhedron:

    The Amplituhedron (21:12 minute mark) – Nima Arkani-Hamed, Professor of Physics, Institute for Advanced Study in Princeton, N.J. – video
    https://www.youtube.com/watch?v=By27M9ommJc#t=1272

    Bohemian Gravity – Rob Sheldon – September 19, 2013
    Excerpt: Quanta magazine carried an article about a hypergeometric object that is as much better than Feynman diagrams as Feynman was better than Heisenberg’s S-matrices.
    http://rbsp.info/PROCRUSTES/bohemian-gravity/

    As well, Alex Vilenkin commenting on Euler’s Identity stated,

    “It appears that the Creator shares the mathematicians sense of beauty”
    Alex Vilenkin – Many Worlds in One: (page 201)
    http://books.google.com/books?.....8;pg=PA201

    And indeed, when mathematicians are shown ‘beautiful’ equations, such as Euler’s identity or the Pythagorean identity, the same area of the brain that is used to appreciate fine art or music lights up:

    Mathematics: Why the brain sees maths as beauty – Feb. 12, 2014
    Excerpt: Mathematicians were shown “ugly” and “beautiful” equations while in a brain scanner at University College London.
    The same emotional brain centres used to appreciate art were being activated by “beautiful” maths.,,,
    One of the researchers, Prof Semir Zeki, told the BBC: “A large number of areas of the brain are involved when viewing equations, but when one looks at a formula rated as beautiful it activates the emotional brain – the medial orbito-frontal cortex – like looking at a great painting or listening to a piece of music.”
    http://www.bbc.com/news/scienc.....t-26151062

    But where this ‘sense of beauty’ in mathematics, that apparently has been so fruitful for science, breaks down is with string theory, and m-theory:

    The part of the book (‘The Trouble With Physics’) I found most interesting was the part which tells how the string theorists were scammed by Nature (or Mathematics). Of course, Smolin doesn’t put it exactly like this, but imagine the following conversation.———
    String theorists: We’ve got the Standard Model, and it works great, but it doesn’t include gravity, and it doesn’t explain lots of other stuff, like why all the elementary particles have the masses they do. We need a new, broader theory.
    Nature: Here’s a great new theory I can sell you. It combines quantum field theory and gravity, and there’s only one adjustable parameter in it, so all you have to do is find the right value of that parameter, and the Standard Model will pop right out.
    String theorists: We’ll take it.
    String theorists (some time later): Wait a minute, Nature, our new theory won’t fit into our driveway. String theory has ten dimensions, and our driveway only has four.
    Nature: I can sell you a Calabi-Yau manifold. These are really neat gadgets, and they’ll fold up string theory into four dimensions, no problem.
    String theorists: We’ll take one of those as well, please.
    Nature: Happy to help.
    String theorists (some time later): Wait a minute, Nature, there’s too many different ways to fold our Calabi-Yao manifold up. And it keeps trying to come unfolded. And string theory is only compatible with a negative cosmological constant, and we own a positive one.
    Nature: No problem. Just let me tie this Calabi-Yao manifold up with some strings and branes, and maybe a little duct tape, and you’ll be all set.
    String theorists: But our beautiful new theory is so ugly now!
    Nature: Ah! But the Anthropic Principle says that all the best theories are ugly.
    String theorists: It does?
    Nature: It does. And once you make it the fashion to be ugly, you’ll ensure that other theories will never beat you in beauty contests.
    String theorists: Hooray! Hooray! Look at our beautiful new theory.
    ———- Okay, I’ve taken a few liberties here. But according to Smolin’s book, string theory did start out looking like a very promising theory. And, like a scam, as it looks less and less promising, it’s hard to resist the temptation to throw good money (or research) after bad in the hope of getting something back for your effort.
    http://www.amazon.com/review/R2H7GVX4BUQQ68/

    A Capella Science – Bohemian Gravity! – video
    https://www.youtube.com/watch?v=2rjbtsX7twc

    Moreover, ‘The argument from beauty’ is a Theistic argument:

    Aesthetic Arguments for the Existence of God:
    Excerpt: Beauty,,, can be appreciated only by the mind. This would be impossible, if this `idea’ of beauty were not found in the mind in a more perfect form.
    http://www.quodlibet.net/artic.....etic.shtml

  3. 3
    Seversky says:

    I don’t understand why people here are so bothered about arcane stuff like string theory. At best it gives us an insight into the underlying structure of the Universe (or multiverse), at worst it’s “Close, but no cigar!” It looks like it’s going to be quite a while before we know one way or the other, so why worry? What difference does it make?

  4. 4
    bornagain77 says:

    on related note to post 2:

    ENV has a article that was, though technical, humorous in detailing the futile attempts of two materialists who tried to reduce the subjective ‘sense of beauty’ to mere material mechanism.,,

    Beauty Evades the Clutches of Materialism – March 27, 2013
    http://www.evolutionnews.org/2.....70321.html

  5. 5
    Silver Asiatic says:

    Seversky

    I don’t understand why people here are so bothered about arcane stuff like string theory. At best it gives us an insight into the underlying structure of the Universe (or multiverse), at worst it’s “Close, but no cigar!” It looks like it’s going to be quite a while before we know one way or the other, so why worry? What difference does it make?

    The reason it is a concern is that it is used to justify lots of things which are difficult for science to explain, like fine-tuning. It’s a theory-of-the-gaps type of thing.

  6. 6
    Seversky says:

    bornagain77 @ 4

    ENV has a article that was, though technical, humorous in detailing the futile attempts of two materialists who tried to reduce the subjective ‘sense of beauty’ to mere material mechanism.,,

    How does explaining how something works “reduce” it? As an aircraft enthusiast I find the British Supermarine Spitfire fighter of World War II to be a beautiful design. I also greatly enjoyed the cutaway drawings that exposed the internal structure of the machine. In their own way, they are just as aesthetically-pleasing to me at least.

    Would understanding the neurological basis of the experience of beauty change it any way? I don’t see that it would. Does our understanding of how the human visual system works change the way we actually see the world in any way? No, it doesn’t although that insight means we can be better prepared to cope with any malfunctions of the system.

  7. 7
    News says:

    For Seversky at 3, why we care: Because if string theory prevails without evidence, “Physics becomes just another player in a culture war, with no more genuinely respectable claims for attention than the demands we hear daily from grievance warriors that their version of events be accepted without cavil as Truth. You could find yourselves currying favour with politicians, as an identity group, for your version of nature versus that of magical thinking. Is that really what you want?” Doubtless, there are many who would find that deeply convenient. We suspect the Nature authors are not of that ilk.

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