Ursprünglich war die Idee, dass wissenschaftlicher Fortschritt kumulativ erfolgt. Wir lernen immer mehr über unsere Umwelt. Jede neue Theorie erklärt, was die alte Theorie erklärt hat und etwas darüber hinaus.
Dann kam Karl Popper mit seinem kritischen Rationalismus und hat den Erkenntnisfortschritt mit einem Scheinwerfer verglichen, der einen bestimmten Bereich erhellt, andere im Dunkeln belässt. Neue Scheinwerfer erhellen nicht unbedingt denselben Bereich, den alte Scheinwerfer erhellt haben.
Schließlich hat Thomas Kuhn Erkenntnisfortschritt als Paradigmenwechsel, als Konversion beschrieben, denn – so seine Begründung – Wissenschaftler, die in einem Paradigma arbeiten, sind blind für Veränderungen und Anomalien, die ihr Paradigma in Frage stellen.
In der Chaostheorie scheinen Popper und Kuhn vereint zu sein:
The Historian of Science Thomas S. Kuhn describes a disturbing experiment conducted by a pair of psychologists in the 1940s. Subjects were given glimpses of playing cards, one at a time, and asked to name them. There was a trick, of course. A few of the cards were freakish: for example, a red six of spades or a black queen of diamonds.
At high speed the subjects sailed smoothly along. Nothing could have been simpler. They didn’t see the anomalies at all. Shown a red six of spades, they would sing out either ‘six of hearts’ or ‘six of spades’. But when the cards were displayed for longer intervals, the subjects started to hesitate. They became aware of a problem but were not sure quite what it was. A subject might say that he had seen something odd, like a red border around a black heart.
Eventually, as the pace was slowed even more, most subjects would catch on. They would see the wrong cards and make the mental shift necessary to play the game without error. Not everyone, though. A few suffered a sense of disorientation that brought real pain. ‘I can’t make that suit out, whatever it is,’ said one. ‘It didn’t even look like a card that time. I don’t know what color it is now or whether it’s a spade or a heart. I’m not sure what as spade looks like. My God!’
Professional scientists, given brief, uncertain glimpses of nature’s workings, are no less vulnerable to anguish and confusion when they come face to face with incongruity. And incongruity, when it changes the way a scientist sees, makes possible the most important advances. So Kuhn argues, and so the story of chaos suggests.
Kuhn’s notion of how scientists work and how revolutions occur drew as much hostility as admiration when he first published them, in 1962, and the controversy has never ended. He pushed a sharp needle into the traditional view that science progresses by the accretion of knowledge, each discovery adding to the last, and that new theories emerge when new experimental facts require them. He deflated the view of science as an orderly process of asking questions and finding their answers. He emphasized a contrast between the bulk of what scientists do, working on legitimate, well-understood problems within their disciplines, and the exceptional, unorthodox work that creates revolutions. Not by accident, he made scientists seem less than perfect rationalists” (Gleick, Chaos, 35-36)