7 The truth, the whole truth and something quite like the truth

7 The truth, the whole truth, and something quite like the truth

You may have heard about ‘paradigm shifts’. If not, let me tell you about a trick with a pack of cards. Thomas Kuhn, the man who came up with the idea of paradigm shifts, tells of an experiment involving a pack of cards with a difference: the pack contained some ‘strange’ cards, like a red six of spades and a black four of hearts. The subjects of the experiment were asked to identify cards from the pack (including the strange ones) as they were shown to them in rapid succession. All the subjects initially perceived the strange cards incorrectly, but as the exposure time lengthened they became confused because they knew the categories they were placing them in were wrong, yet they neither knew why nor what to do about it. With further lengthening of exposure time, most of the subjects realized that this or that card was the wrong colour, and after a few more goes they could accurately identify all the cards. A few of the subjects, however, just could not make the necessary adjustment; even when the exposure time was increased by forty times that normally needed to recognize a card, more than 10 per cent of the strange cards were not correctly identified. These subjects then became deeply distressed; one of them exclaimed, ‘I can’t make the suit out, whatever is it. It didn’t even look like a card that time. I don’t know what colour it is now or whether it’s a spade or a heart. I’m not even sure now what a spade looks like. My God!’…