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Thursday, November 17, 2011

Physics Today on the big paradigms

Steven Sherwood writes in Physics Today about science controversies and paradigm shifts:
Reactions to the science of global warming have followed a similar course to those of other inconvenient truths from physics. ...

The decision [whether to accept the new theory] was not exclusively, or even primarily, a matter for astronomers, and as the debate spread from astronomical circles it became tumultuous in the extreme. To most of those who were not concerned with the detailed study of celestial motions, Copernicus’s innovation seemed absurd and impious. Even when understood, the vaunted harmonies seemed no evidence at all. The resulting clamor was widespread, vocal, and bitter.2

Thus does science historian Thomas Kuhn describe the difficulties experienced by astronomers in convincing the public of the heliocentric theory of the solar system, which ultimately ushered in the scientific revolution. The “clamor” prevailed around the time of Galileo Galilei, more than a half century after Nicolaus Copernicus, on his deathbed, published the heliocentric model in 1543. Copernicus’s calculations surpassed all others in their ability to describe the observed courses of the planets, and they were based on a far simpler conception. Yet most people would not accept heliocentricity until two centuries after his death.

Why did it take so long? To modern minds, the Ptolemaic model of the solar system, with its nested cycles and epicycles, seems rather silly. Surely, the need for a new tweak to the model each time more accurate observations came along should have been a tip-off that something fundamental was wrong. The heliocentric model’s elegance and simplicity, on the other hand, are now appreciated as the hallmarks of credibility for a scientific theory.
When people lecture us on the progress of science, they often cite Copernicus, Galileo, and Einstein as their favorite examples. But they nearly always get the facts wrong, as I detail in my book.

This is important because it leads to some lesson about climate change, or some other very important policy issue of the day. If the examples are wrong, then the science policy argument is probably wrong also.

In the cases of Copernicus, Galileo, and Einstein, the facts are extremely well documented, and there is no excuse for getting them wrong. They get them wrong for ideological reasons.

The above descriptions are nonsense. Copernicus did not have superior calculations, and his model was no simpler or more accurate. The Ptolemaic system did not have nested epicycles. The idea of heliocentrism did not eliminate the need to tweak the model. It is true that a lot of astronomers of the day did not accept the Copernicus model, but it is for scientific reasons that Copernicus could not answer.
Even Albert Einstein was not immune to political backlash. His theory of general relativity, excerpted on the notebook page in figure 2, undermined our most fundamental notions of absolute space and time, a revolution that Max Planck avowed “can only be compared with that brought about by the introduction of the Copernican world system.”5 Though the theory predicted the anomalous perihelion shift of Mercury’s orbit, it was still regarded as provisional in the years following its publication in 1916.
Planck said that in 1910, so he was talking about special relativity, not general relativity.

Here is the lesson -- trust the experts:
It was easy for those not wishing to accept Copernicus’s insight to devise persuasive counterarguments against it. For example, in 1597 one prominent commentator declared that a moving Earth would “see cities and fortresses, towns and mountains thrown down,” and that “neither an arrow shot straight up, nor a stone dropped ... would fall perpendicularly.”2 Those arguments would not fly today because nearly everyone has experiential knowledge, from riding in cars and airplanes, of what are now called the Galilean principles of invariance. But laypeople in the 17th century did not. To explain those abstractions to them would have been much more difficult than to make the neat, simple, and wrong argument advanced by naysayers. As the 17th century progressed, arguments against heliocentricity tended to veer more toward scriptural rather than scientific ones, but both types persisted.

Greenhouse warming today faces an even greater array of bogus counterarguments based on the uninformed interpretation of data from ice cores, erroneous views about natural carbon sources, alleged but unobserved alternative drivers of climate change, naive expectations of the time scales over which models and observations should match, and various forms of statistical chicanery and logical fallacy. Many of the arguments sound reasonable to an inexpert but intelligent layperson. Critics use the alleged ?aws to attempt to discredit the entire field.

Debates between mainstream scientists and silver-tongued opponents cannot be won by the side of truth no matter how obvious the fallacies may be to an expert.
If you subscribe to Kuhn's philosophy, there is no such thing as truth anyway. You cannot hope to make your own independent assessment of what is correct. You just have to trust the experts who are following the right paradigm.

Here is a current example of experts demanding that we accept their policy recommendations:
"More than 99 percent of the medical/scientific world simply are not wrong," Kaplan said. "Moderate salt reduction is an absolute necessity and can be attained by deletion of some of the salt added to virtually all processed food."
I suspect that these experts are wrong. They have done lots of studies on low-salt diets. The diets help some people lower their blood pressure, but that is about all. For most people, there is no measurable benefit to a low-salt diet.

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