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Monday, August 15, 2011

Scientific Methhod-Karl Popper

Karl Popper is prescriptive, and describes what science should do (not how it actually behaves). Popper is a rationalist and contended that the central question in the philosophy of science was distinguishing science from non-science.

Early attempts by the positivists grounded science in observation while non-science was non-observational and hence nonsense. Popper is known for his attempt to refute the classical positivist account of scientific method by advancing empirical falsification.

Popper believes scientific knowledge is provisional – the best we can do at the moment.

Karl Popper in The Logic of Scientific Discovery emerged as a major critic of inductivism, which he saw as an essentially old-fashioned strategy. Popper replaced the classical observationalist-inductivist account of scientific method with falsification as the criterion for distinguishing scientific theory from non-science.

Karl Popper was critical of the inductive methods used by science. The empiricist David Hume (1711-76) had argued that there were serious logical problems with induction. All inductive evidence is limited: we do not observe the universe at all times and in all places. We are not justified therefore in making a general rule from this observation of particulars.

Popper gives the following example. Europeans for thousands of years had observed millions of white swans. Using inductive evidence, we could come up with the theory that all swans are white. However exploration of Australasia introduced Europeans to black swans. Poppers' point is this: no matter how many observations are made which confirm a theory there is always the possibility that a future observation could refute it. Induction cannot yield certainty.

According to Popper, scientific theory should make predictions which can be tested and the theory rejected if these predictions are shown not to be correct. He argued that science would best progress using deductive reasoning as its primary emphasis, known as critical rationalism. His astute formulations of logical procedure helped to reign in the excessive use of inductive speculation upon inductive speculation, and also helped to strengthen the conceptual foundation for today's peer review procedures.

Karl Popper was also critical of the naive empiricist view that we objectively observe the world. Popper argued that all observation is from a point of view, and indeed that all observation is coloured by our understanding. The world appears to us in the context of theories we already hold: it is 'theory laden'.

Popper proposed an alternative scientific method based on falsification. However many confirming instances there are for a theory, it only takes one counter observation to falsify it. Science progresses when a theory is shown to be wrong and a new theory is introduced which better explains the phenomena. For Popper the scientist should attempt to disprove his/her theory rather than attempt to continually prove it. Popper does think that science can help us progressively approach the truth but we can never be certain that we have the final explanation.

A theory is scientific, then, if we can say what would possibly cause us to reject it.

"Popper’s first major contribution to philosophy was his novel solution to the problem of the demarcation of science. According to the time-honoured view, science, properly so called, is distinguished by its inductive method – by its characteristic use of observation and experiment, as opposed to purely logical analysis, to establish its results. The great difficulty was that no run of favourable observational data, however long and unbroken, is logically sufficient to establish the truth of an unrestricted generalization.

Critical Evaluation

The history of science gives little indication of having followed anything like a methodological falsificationist approach. Indeed, and as many studies have shown, scientists of the past (and still today) tended to be reluctant to give up theories that we would have to call falsified in the methodological sense; and very often it turned out that they were correct to do so (seen from our later perspective). For example, "In the early years of its life, Newton’s gravitational theory was falsified by observations of the moon’s orbit"

One observation does not falsify a theory. The experiment may have been badly designed, data could be incorrect.

Quine states that a theory is not a single statement; it is a complex network (a collection of statement).

You might falsify one statement (e.g. all swans are white) in the network, but this should not been you should reject the whole complex theory.

The history of science shows that sometimes it is best to ’stick to one’s guns’, cf. Galileo even if your theory has been falsified.

Critics of Popper, chiefly Thomas Kuhn, Paul Feyerabend and Imre Lakatos, rejected the idea that there exists a single method that applies to all science and could account for its progress.

Lecture notes prepared by Biju P R,Assistant Professor in Political Science,GBC TLY

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