Saturday, December 22, 2012

String theory races for Kuhnian glory

Chemist Ashutosh (Ash) Jogalekar writes in SciAm:
Freeman Dyson has a perspective in this week’s Science magazine in which he provides a summary of a theme he has explored in his book “The Sun, the Genome and the Internet”. Dyson’s central thesis is that scientific revolutions are driven as much or even more by tools than by ideas. This view runs somewhat contrary to the generally accepted belief regarding the dominance of Kuhnian revolutions – described famously by Thomas Kuhn in his seminal book “The Structure of Scientific Revolutions” – which are engineered by ideas and shifting paradigms. In contrast, in reference to Harvard university historian of science Peter Galison, Dyson emphasizes the importance of Galisonian revolutions which are driven mainly by experimental tools.

As a chemist I find myself in almost complete agreement with the idea of tool-driven Galisonian revolutions.
Dyson writes:
Thomas Kuhn was a theoretical physicist before he became a historian. He saw the history of science through the eyes of a theorist. He gave us an accurate view of events in the world of ideas. His favorite word, “paradigm,” means a system of ideas that dominate the science of a particular place and time. A scientific revolution is a discontinuous shift from one paradigm to another. The shift happens suddenly because new ideas explode with a barrage of new insights and new questions that push old ideas into oblivion. I remember the joy of reading Kuhn's book, The Structure of Scientific Revolutions, when it first appeared in 1962. It made sense of the relativity and quantum revolutions that had happened just before the theoretical physicists of my generation were born. Those were revolutions led by deep thinkers — Einstein and Heisenberg and Schrödinger and Dirac — who guessed nature's secrets by dreaming dreams of mathematical beauty. Their new paradigms were created out of abstract ideas. In those revolutionary years from 1900 to 1930, ideas led the way to understanding.
These guys are badly confused. A Kuhnian paradigm shifts is a reformulation of a scientific theory that is has no measurable advantage to the previous theory. The canonical examples are Copernican heliocentrism and Einstein's 1905 relativity paper. Kuhn wrote a whole book on the dawn of quantum mechanics, and did not say that it was a revolution or paradigm shift.

The term paradigm shift is also used by crackpots who complain that the science establishment is ignoring their silly ideas.

The Copernican revolution was the Earth revolving around the Sun. It was a different point of view, but did not approximate the observable orbits any more accurately.

Einstein's 1905 relativity was essentially the same as Lorentz's, with minor technical differences.

Dyson ends up concluding that string theory and multiverse speculations are entirely Kuhnian:
At the beginning of the 21st century, we find ourselves in a situation reminiscent of the 1950s. Once again, the community of physi-cists is split into Kuhnians and Galisonians. The most ambitious of the Kuhnian programs is string theory, building a grand and beauti-ful structure out of abstract mathematics and hoping to find it somehow mirrored in the architecture of the universe. This program is not an isolated one-man show like Einstein’s unified field theory. String theory is a collec-tive enterprise combining the efforts of thou-sands of people in hundreds of universities. These people are the best and the brightest of their generation, most of them young and many of them brilliant. Their work is admired by the pure mathematicians who share their ideas and speak their language. String theory, as a solid part of modern mathematics, is here to stay. But meanwhile, Galisonian science is continuing to forge ahead, exploring nature without paying attention to string theory. The great recent discoveries in the physical sci-ences were dark matter and dark energy, two mysterious monsters together constituting 97% of the mass of the universe. These dis-coveries did not give rise to new paradigms. ...

We are standing now as we stood in the 1950s, between a Kuhnian dream of sudden illumination and a Galisonian reality of labo-rious exploring. On one side are string theory and speculations about multiverses; on the other are all-sky surveys and observations of real black holes. The balance today is more even than it was in the 1950s. String theory is a far more promising venture than Einstein’s unified field theory. Kuhn and Galison are running neck and neck in the race for glory. We are lucky to live in a time when both are going strong.
I agree that string theory and multiverse theory are Kuhnian in that they have no hope of making any measurable progress in our understanding of the world, and that belief in them is not rational. It is only because of Einsteinian-Kuhnian thinking that there is any glory in such activity.

In a companion essay (also behind a paywall), molecular biologist Sydney Brenner argues:
It seems remark-able that historians once thought that science
progressed by the steady addition of knowl-edge, building the edifice of scientific truth, brick by brick. In his 1962 book The Struc-ture of Scientific Revolutions, Thomas Kuhn argued that progress occurs in revolutionary steps by the introduction of new paradigms, which may be new theories—new ways of looking at the world—or new technical meth-ods that enhance observation and analysis. Between Kuhn’s revolutions, scientific knowledge does advance by accretion, as there is much to do to consolidate the new sci-ence. But then, inevitably, unsolved problems accumulate and, in many cases, the inconsis-tencies have been put to one side and every-body hopes that they will quietly go away. The edifice becomes rickety; some of its founda-tions are insecure and many of the bricks have not been well-baked. This is when a new rev-olutionary wave in the form of new ideas or new techniques appears, which allows us to condemn and demolish the unsafe or corrupt parts of the edifice and rebuild truth. Often there is great resistance to the new wave, but as Max Planck pointed out, it succeeds because the opponents grow old and die. The process is then repeated: The radicals become liberals, the liberals become conservatives, the conservatives become reactionaries, and the reactionaries disappear. Students of evolu-tion will recognize this process in the theory of punctuated equilibrium: Organisms stay much the same for very long periods of time; this is interrupted by bursts of change when novelty appears, followed again by stasis. The life sciences have undergone a radical revolution in my lifetime, and it is interesting to view this from the vantage point of the pres-ent to understand its full meaning and impact. In the first half of the 20th century, physics underwent two revolutions: Einstein’s theory of relativity, connected with large scales of time and space, and quantum mechanics, con-cerned with the very small and dealing with fundamental questions of matter and energy. ...

We can now see exactly what consti-tuted the new paradigm in the life sci-ences: It was the introduction of the idea of information and its physical embodiment in DNA sequences of four different bases. Thus, although the components of DNA are simple chemicals, the complexity that can be generated by different sequences is enormous. In 1953, biochemists were pre-occupied only with questions of matter and energy, but now they had to add informa-tion.
It is amazing how otherwise-intelligent scientists fall for this nonsense. The discovery of DNA sequences was not like what Kuhn described as a paradigm shift. It was not just an incommensurable new view on an old theory. It did not succeed because the opponents grew old and die. The first Nobel prize for relativity was in 1902 to Lorentz and for quantum mechanics in 1918 (Planck) and 1922 (Bohr). Heisenberg, Schrödinger, and Dirac got their prizes in 1932-33 for work done only about 5 years earlier. Compare that to string theory and multiverse theory, where no one has ever gotten a Nobel prize.

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