“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.
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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
“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
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’:
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,
As well, Dyson considered Higg’s mathematical work to be ‘beautiful’:
‘Mathematical beauty’ even had a guiding hand in the discovery of the Amplituhedron:
As well, Alex Vilenkin commenting on Euler’s Identity stated,
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:
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:
Moreover, ‘The argument from beauty’ is a Theistic argument:
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?
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
Seversky
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.
bornagain77 @ 4
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.
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.