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The Impact of Science

A Brief History of… Philosophy of Science

Rick Lewis describes what philosophers have thought about science over the last century and a half.

The French philosopher and sociologist Auguste Comte (1798-1857) followed Immanuel Kant in believing that the true nature of things is unknowable; all we can know is the world of phenomena – of appearances. Comte therefore distrusted scientific ‘explanations’ of an underlying reality and believed that the purpose of science is just to make successful predictions about the world. The method he recommended for doing science, which he called ‘positivism’, is based on observation alone. Observations should be recorded and from those observations, predictions can be made about what will be observed in the future, using what he called ‘laws of succession’. He thought that to go beyond this and theorize about the unobservable underlying causal mechanisms was asking for trouble – it would lead to mistaken preconceptions, mis-observation to fit favoured theories and so on.

Logical Positivism and the Vienna Circle

The Vienna Circle – a group of philosophers who met in that city in the 1920s and 30s – went further than Comte. They said that a statement was only meaningful if it had the potential to be verified. They believed that this was the dividing line between scientific and non-scientific statements and between sense and nonsense. A proposition that couldn’t potentially be verified was strictly meaningless. Most statements about religion, ethics and metaphysics fell into that category and were dismissed at a stroke. This approach was brilliantly popularized in the English-speaking world by A.J.Ayer through his book Language, Truth and Logic.

According to its many critics, logical positivism is selfrefuting. It says that statements which can’t be verified are nonsense – but this statement itself can’t be verified, so it must be nonsense.

Karl Popper and Falsificationism

Karl Popper spotted a fundamental flaw in verificationism. Take for instance the proposition that “all swans are white.” Popper pointed out that however many times you observe white swans, you can never conclusively say you have proved the proposition, because there is always the possibility that the next swan you see will be some other colour. A single, solitary sighting of a swan that isn’t white will have the effect of disproving the proposition. Therefore, he said, the true mark of a scientific statement isn’t that it has the potential to be verified, but that it has the potential to be falsified.

The problem here is that science simply doesn’t work this way. According to Popper, a single observation which falsifies a theory should lead to that theory being abandoned. This almost never happens. For instance, Isaac Newton’s theory of gravitation was refuted almost at birth by the observed motion of the Moon. However, this evidence was cheerfully ignored and Newton’s theories went on to very fruitfully dominate science for over two hundred years.

Imre Lakatos

One attempt to modify Popper’s ideas to take this into account was by Imre Lakatos, a Hungarian emigré who taught at the London School of Economics. He described his ideas in The Methodology of Scientific Research Programmes. According to Lakatos, the basic unit of science is the ‘research programme’ – examples would be Newtonian science and quantum physics. A research programme consists of a core of central hypotheses which are rarely falsified, surrounded and protected by a band of secondary hypotheses which can be falsified. If a central hypothesis is threatened by new evidence, then rather than chuck out the entire research programme, scientists tend to invent a ‘rescue hypothesis’ to explain away the new findings. Young, vigorous research programmes make predictions, said Lakatos, but eventually they become ‘degenerate’: they no longer generate predictions and their adherents spend most of their efforts trying to defend the programme’s core theses against mountains of contrary evidence. Lakatos (an ex-Communist) saw Marxism as an example of a degenerate research programme.

Thomas Kuhn

While Lakatos basically tried to improve Popper’s falsificationism, Thomas Kuhn turned his back on Popper altogether. In his book The Structure of Scientific Revolutions, Kuhn said that scientific revolutions occur which are primarily sociological events. When a whole new set of ideas (or new ‘paradigm’ as Kuhn called it) takes hold, adherents of the old paradigm are seen as old-fashioned and find it difficult to get jobs, promotions or research funding. Therefore, unless they embrace the new paradigm, they are eased out of academia. In this way, the new paradigm comes to dominate science for a while. Between revolutions, in periods of what Kuhn calls ‘normal science’, things progress pretty much as Popper described.

Paul Feyerabend

Finally, Paul Feyerabend (1924-94) thought that scientific observation statements themselves always, necessarily, embody a theory, and argued for ‘democratic’ control of science…

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