Popper, Science & Democracy

Brian King follows Popper's idea of the evolution of knowledge, life and society.

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In an age in which both science and pseudoscience are more prominent than ever, it is useful to have a way to distinguish between them. The Austrian-British philosopher of science Sir Karl Popper (1902-94) gave us just that, in his 1934 book The Logic of Scientific Discovery. He called it falsification. A truly scientific theory, he said, consists of statements that can be rigorously tested against the evidence and potentially found to be false. Popper claimed that falsifiability is the key feature differentiating science from all other ways of thinking.

Ever since Aristotle in ancient times and Francis Bacon four hundred years ago, inductive logic was thought of as the method by which scientists discovered laws of nature. The sight of one white swan after another leads us to the theory that 'all swans are white' - in effect, a generalisation. However, as David Hume (1711-76) noted, the problem is that the generalisation does not logically follow. The more white swans you see, the more you might think the law 'All swans are white' is true - but this is just a psychological point about the way we think, not a point about the natural world, or swans. In fact, the only legitimate derivation would be that 'all swans seen so far are white'. And to argue that the future will always be like the past because it always has been, would be a circular argument - assuming what you are trying to prove. Moreover, the observation of black swans in Australia immediately disproved the law that 'all swans are white', showing that inductive generalisations can be disproved with one counter-instance. Popper develops this point in a falsificationist direction by writing,