What is Scientific Progress?

progress
In the history of science there are, for good reasons, no episodes that illustrate precisely such a
divergence between truth and rationality. Most scientists have been pretty rational and science as a
whole is moderately if imperfectly rational. There are some exceptions to the latter. As is well
known Réné Blondlot believed in the existence of what he called N-rays for what it is clear were
entirely spurious and irrational reasons. Imagine for sake of argument that we were to discover that
there are in fact hitherto unobserved entities answering to Blondlot’s description of N-rays. So
Blondlot’s belief in N-rays would have been true but unjustified and not knowledge. The semantic
approach would have to regard Blondlot’s belief (which was widely shared in France) as
constituting progress. That is clearly wrong.
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fig 2.1 (c)
Cases such as Blondlot’s are atypical. There are actual (rather than imaginary) cases of true
scientific beliefs that were not knowledge. But because of the general rationality of science, there
beliefs will typically have had at least some confirmation. Hence we are entitled to show some
admiration for scientists who got it right but lacked the evidence to prove their hypotheses.
Aristarchus of Samos proposed a heliocentric system 2,000 years before Copernicus, with the
geocentric views of Aristotle and Ptolemy filling the intervening gap. Alfred Wegener famously
proposed the theory of continental drift over half a century before it became accepted. We might be
tempted to think that science missed a trick or two here. Would it not have been more progressive to
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