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No. 70: Jul-Aug 1990

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Successful Predictions Mean Little In Science

Many maverick scientists make the pages of Science Frontiers because they are the ones who deviate from the mainstream. They pursue those Anomalies that the Sourcebook Project filters from the great river of scientific literature. But enough fluvial allusions! The maverick here is, again, H. Alfven. We first met Alfven in SF#59,where we commented on his paper "Memoirs of a Dissident Scientist." Alfven is still a dissident, a scientist who has the temerity to claim that cosmic rays have a local rather than galactic origin. Even more heretical is his assertion that electromagnetic forces have shaped the universe rather than the Big Bang!

The subject of this entry is not so much Alfven's conflicts with accepted scientific views, but rather whether correct scientific predictions really influence the scientific community's acceptance of theories. This, after all, is what science is all about. It turns out that Alfven has made many correct scientific predictions. (He even shared a Nobel Prize in 1970.) But, as S.G. Brush has related in a detailed article in Eos, being correct is not the same as being accepted.

"According to some scientists and philosophers of science, a theory is or should be judged by its ability to make successful predictions. This paper examines a case from the history of recent science - the research of Hannes Alfven and his colleagues on space plasma phenomena - in order to see whether scientists actually follow this policy. Tests of five pre-dictions are considered: magnetohydrodynamic waves, field-alligned ('Birkeland') currents, critical ionization velocity and the existance of planetary rings, electrostatic double layers, and partial corotation. It is found that the success or failure of these predictions had essentially no effect on the acceptance of Alfven's theories, even though concepts such as 'Alfven waves' have become firmly entrenched in space physics. Perhaps the importance of predictions in science has been exaggerated; if a theory is not acceptable to the scientific community, it may not gain any credit from successful predictions."

Brush concludes that the continuing resistance to Alfven's work is due to the widely held opinion that his theory is not plausible; that is, it does not conform to the dominant paradigm.

(Brush, Stephen G.; "Prediction and Theory Evaluation," Eos, 71:19, 1990. Cr. L. Ellenberger)

Comment. In other words science does not always work as it is supposed to.

From Science Frontiers #70, JUL-AUG 1990. � 1990-2000 William R. Corliss