Falsificationism Falsified

Now, Newton’s theory of gravitation, Einstein’s relativity theory, quantum mechanics, Marxism, Freudism, are all research programmes, each with a characteristic hard core stubbornly defended, each with its more flexible protective belt and each with its elaborate problem-solving machinery. Each of them, at any stage of its development, has unsolved problems and undigested anomalies. All theories, in this sense, are born refuted and die refuted. But are they equally good? Until now I have been describing what research programmes are like. But how can one distinguish a scientific or progressive programme from a pseudoscientific or degenerating one?

Contrary to Popper, the difference cannot be that some are still unrefuted, while others are already refuted. {When Newton published his Principia, it was common knowledge that it could not properly explain even the motion of the moon; in fact, lunar motion refuted Newton.} Kaufmann, a distinguished physicist, refuted Einstein’s relativity theory in the very year it was published. But all the research programmes I admire have one characteristic in common. They all predict novel facts, facts which had been either undreamt of, or have indeed been contradicted by previous or rival programmes. In 1686, when Newton published his theory of gravitation, there were, for instance, two current theories concerning comets. The more popular one regarded comets as a signal from an angry God warning that He will strike and bring disaster. A little known theory of Kepler’s held that comets were celestial bodies moving along straight lines. Now according to Newtonian theory, some of them moved in hyperbolas or parabolas never to return; others moved in ordinary ellipses. Halley, working in Newton’s programme, calculated on the basis of observing a brief stretch of a comet’s path that it would return in seventy-two year’s time; he calculated to the minute when it would be seen again at a well-defined point of the sky. This was incredible. But seventy-two years later, {when both Newton and Halley were long dead,} Halley’s comet returned exactly as Halley predicted. Similarly, Newtonian scientists predicted the existence and exact motion of small planets which had never been observed before. Or let us take Einstein’s programme. This programme made the stunning prediction that if one measures the distance between two stars in the night and if one measure the distance between them during the day (when they are visible during an eclipse of the sun), the two measurements will be different. Nobody had thought to make such an observation before Einstein’s programme. Thus, in a progressive research programme, theory leads to the discovery of hitherto unknown novel facts.

— Lakatos, Science and Pseudoscience