Friday, December 18, 2015

Has physics outgrown Popperian falsification?

Physics has been in trouble for awhile because theories (e.g. string theory in all its forms) now seem to be beyond empirical test. What to do? Is Popper out and Bayes in? – A question posed at a recent meeting of physicists and philosophers in Germany:
But, as many in Munich were surprised to learn, falsificationism is no longer the reigning philosophy of science. Massimo Pigliucci, a philosopher at the Graduate Center of the City University of New York, pointed out that falsifiability is woefully inadequate as a separator of science and nonscience, as Popper himself recognized. Astrology, for instance, is falsifiable — indeed, it has been falsified ad nauseam — and yet it isn’t science. Physicists’ preoccupation with Popper “is really something that needs to stop,” Pigliucci said. “We need to talk about current philosophy of science. We don’t talk about something that was current 50 years ago.”

Nowadays, as several philosophers at the workshop said, Popperian falsificationism has been supplanted by Bayesian confirmation theory, or Bayesianism, a modern framework based on the 18th-century probability theory of the English statistician and minister Thomas Bayes. Bayesianism allows for the fact that modern scientific theories typically make claims far beyond what can be directly observed — no one has ever seen an atom — and so today’s theories often resist a falsified-unfalsified dichotomy. Instead, trust in a theory often falls somewhere along a continuum, sliding up or down between 0 and 100 percent as new information becomes available. “The Bayesian framework is much more flexible” than Popper’s theory, said Stephan Hartmann, a Bayesian philosopher at LMU. “It also connects nicely to the psychology of reasoning.”
Of course, it is not physics so much that interests me. It is literature, culture, and the mind. How do we determine objective truth about such phenomena?


  1. David Deutsch's second book, The Beginning of Infinite, devotes quite a few pages to science as the "search for good explanations". Falsifiability is only a piece of what makes them good. Resistance to easy change, explanatory power, are among the other attributes.

    I don't think he mentions Bayes.

    1. Thanks, Rich. Have you read any of his latest stuff on computation?