Wednesday, 14 May 2014

Scientists have proved that …

Oh no they haven’t. Not according to one model or theory, widely held among philosophers of science, of what science is all about.

Most of the time scientists do ‘Ordinary science’: tests and analyses in line with well-established investigatory norms. But the great ground-breaking scientists are on a par with the poets, composers and painters: their work is creative and speculative. Such a scientist might, for instance, come up with the wild idea that when a piece of wood burns, and a piece of iron rusts, what is happening, for all the apparent dissimilarity, is in some sense one and the same: after all, the wood won’t burn and the iron won’t rust if there is no air. Could it be that the wood and the iron are reacting to or with, perhaps combining with, something in the air? ‘But if that were so,’ he says to himself, ‘Then it would follow that…’ and this is where the hard work that follows, in science as in the (other) arts, on the original inspiration or epiphany really starts: the scientist devises an experiment to see if the ‘It would follow that…’ really does follow.

If it does, then if he’s a good scientist his self-congratulation will be short-lived. He will try the experiment again and perhaps get colleagues to try it: maybe it was chance, or wishful thinking nudging his elbow as he added some reagent. And he will devise further experiments to test further implications of his great over-arching, explanatory, or at least comprehensively descriptive idea.

The important thing to note is that none of these experiments will, or will even be intended to, ‘prove’ or even ‘confirm’ his theory: their results may be consistent with his theory, but the intention of the experiments is actually to try and punch a big hole in it.

Let us assume — and it has often happened — that none of these hole-punching attempts succeed. The theory, as people carelessly say, ‘Stands the test of time.’ After decades or centuries people come to accept it as fact, though actually it never achieves that status: it remains no more than a working hypothesis.

The implication of this model of the scientific enterprise is paradoxical, indeed many find it deeply disturbing: there are (in fact) no scientific facts.

So the next time you hear ‘Scientists have proved that…’  do remember to shout, like a child at a pantomime, ‘OH NO THEY HAVEN’T!’

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