Francis Bacon
Karl Popper
Thomas Kuhn
The Logicof ScientificDiscovery
•Hypothesistesting
Asymmetry
•Negativeevidence
•Positiveevidence
Logicalasymmetry
•The onlyrelevantevidence isnegativeevidence
•Scientistsshouldrefute theirhypothesis
Popper was very fond of a picture of scientificevolution modelled on natural selection. Thatanalogy may be genuinely helpful in somerespects, but the idea that hypothesisgeneration is like random mutation ispotentially misleading.
Hypothesis generation is highly constrainedand directed, and would have to be if science ispossible at all.
Popper’s second idea of testing as falsificationhas also been criticised in the context of purescience, and this too may face specialadditional difficulties in the context ofengineering.
Popper has been criticised for making it soundas though hypotheses are much easier torefute than they really are. Nevertheless, hislogical point is sound.
Kuhn’s big idea is also a contrast, but it is thecontrast between rules for research and whathe called exemplars, the core meaning of hisnotorious and protean term ‘paradigm’.
How do exemplars differ from rules? Kuhn wasstruck by a feature of research during periodsof what he came to call ‘normal science’.
Members of the research community in aparticular speciality act as if they shared thesame rules of research.
tend to agree on which are the importantproblems
tend to agree on how those problems shouldbe tackled
tend to agree on the appropriate standardsfor judging whether a particular solution issound
Exemplars are neither rules nor generalprinciples. Rather, they are specific, canonicalproblem solutions in a particular scientificspecialty.
They are particular solutions, but theynevertheless function as general modelsbecause, according to Kuhn, they set upsimilarity relations, so that the scientists canwork by imitation and analogy rather than byrules.
Because of the similarity relations that theexemplars elicit, certain unsolved problemscome to look similar to the problems that theexemplars solve.
Those are the problems the scientist will pick,the outstanding problems that look likeproblems that have already been solved, andso the problems for which there seems everypossibility of successful solutions.
Scientists will naturally try to apply techniquessimilar to those that worked so well in theexemplars.
That is only rational: since the problems wereselected because of their perceived similarity toproblems the scientists have already solved,they will try similar solutions to see whetherthey work on the new problems.
And finally the standards by which the scientistjudges the new solutions will be the standardsthat are embodied in the original exemplars.
So, although exemplars differ from rules intheir content, they are similar to rules in theirfunctions.
Exemplars are specific in content, but generalin import and, according to Kuhn, theystructure scientific research, guiding scientistsin the selection of new problems, in theconstruction of possible solutions, and in theevaluation of the solutions proposed.
NormalScience
Crisis
Revolution
Scientist
Engineer
Wildly intelligent
Unconventional
Full of newideas
Earnest
Hard-working
Intellectuallyconservative
The history of science is a graveyard of putativeentities that turn out not to exist, of putativeprocesses that turn out not to take place and oftheories that turn out to be false.
Almost every scientific theory, more than -choose your own figure - 150 or 200 years old,we now know to be, strictly speaking, false.
All past theories have been found to be falseand therefore it is very likely that all presenttheories and, probably, all future theories, willeventually be found to be false as well.
Our best current theories may look terrific atthe moment. If we step back a little andachieve some historical perspective, we shouldsay that it is just a matter of time before thewarts start to show. We will find out that we arewrong now, as we were in the past.
Thornton, Stephen (2006). "Karl Popper". StanfordEncyclopedia of Philosophy.http://plato.stanford.edu/entries/popper/. Retrieved 2007-12-01.
Popper, Karl The Logic of Scientific Discovery, London:Hutchinson, 1959.
Popper, Karl (2004 reprint). The logic of scientific discovery.London & New York: Routledge Classics. ISBN 0-415-27844-9.
Kuhn, Thomas The Structure of Scientific Revolutions, 2nd ed.,Chicago: University of Chicago Press, 1970.
Kuhn, Thomas The Essential Tension, Chicago: University ofChicago Press, 1977.
Putnam, Hillary Meaning and the Moral Sciences, London:Hutchinson, 1978.
Lipton, Peter Inference to the Best Explanation 2nd edition,London: Routledge, 2004.
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