Tuesday, 16 September 2008

The Structure of Scientific Revolution - Thomas Kuhn

Kuhn believes strongly in the textbook as source view of education – when science reaches textbooks it has become the established paradigm.

P28 Perhaps it is not apparent that a paradigm is prerequisite to the discovery of laws such as these. We often hear that they are found by examining measurements undertaken for their own sake and without theoretical commitment. But history offers no support for so excessively Baconian a method.

P47 On the contrary the process of learning a theory depends upon the study of applications, including practice problem-solving both with a pencil and paper and with instruments in the laboratory. If, for example the student of Newtonian dynamics ever discovers the meaning of terms like 'force,' 'mass,' 'space,' and 'time,' he does so less from the incomplete though sometimes helpful definitions in his text than by observing and participating in the application of these concepts to problem-solving.

P59 The Discovery of X-rays meant that previous science had to be re-evaluated considering this new phenomenon which had not previously detected.

Previously completed work on normal projects would now have to be done again because earlier scientists had failed to recognize and control a relevant variable. X-rays, to be sure, opened up a new field and thus added to the potential domain of normal science. But they also, and this is now the more important point, changed fields that had already existed.

P63 An experiment where some playing cards are replaced by anomalous cards (e.g. red six of spades) to see how response depends on exposure times.


P77 This is a direct attack on Popper and The Logic of Scientific Discovery. It is true that usually we just add exceptions to the rule and make the models more complex rather than reject them – for example the standard model and the epicycles of the Ptolemaic System

These hint what our later examination of paradigm rejection will disclose more fully: once it has achieved the status of paradigm, a scientific theory is declared invalid only if an alternate candidate is available to take its place. No process yet disclosed by the historical study of scientific development at all resembles the methodological stereotype of falsification by direct comparison with nature.

P80 But science students accept theories in the authority of teacher and text, not because of evidence. What alternatives do they have, or what competence?

P82 There are always difficulties somewhere in the paradigm-nature fit; most of them are set right sooner or later, often by processes that could not have been foreseen. The scientist who pauses to examine every anomaly he notes will seldom get significant work done.

P84 On other occasions the problem resists even apparently radical new approaches. Then scientists may conclude that no solution will be forthcoming in the present state of their field. The problem is labeled and set aside for a future generation with more developed tools. Or, finally, the case that will most concern us here, a crisis may end with the emergence of a new candidate for paradigm and with the ensuing battle over its acceptance.

P87 Simultaneously, since no experiment can be conceived without some sort of theory, the scientist in crisis will constantly try to generate speculative theories that, if successful, may disclose the road to a new paradigm and, if unsuccessful, can be surrendered with relative ease.

P88 It is, I think, particularly in periods of acknowledged crisis that scientists have turned to the philosophical analysis as a device for unlocking the riddles of their field.

P90 Almost always the men who achieve these fundamental inventions of a new paradigm have been either very young or very new to the field whose paradigm they change.

P91 The proliferation of competing articulations, the willingness to try anything, the expression of explicit discontent, the recourse to philosophy and to debate over fundamentals, all these are symptoms of a transition from normal to extraordinary research.

P119 Galileo was not raised completely as an Aristotelian. On the contrary he was trained to analyze the motions in terms of the impetus theory, a late medieval paradigm which held that the continuing motion of a heavy body is due to an internal power implanted in it by the projector that initiated its motion.

P126 But is sensory experience fixed and neutral? Are theories simply man-made interpretations of given data? The epistemological viewpoint that has most often guided Western philosophy for three centuries dictates an immediate and unequivocal Yes! In the absence of a developed alternative, I find it impossible to relinquish entirely that viewpoint. Yet it no longer functions effectively, and attempts to make it do so through the introduction of a neutral language of observations now seems to me hopeless.

P135 But it is hard to make nature fit a paradigm … Instead, even after accepting the theory, they had still to beat nature into line, a process which, in the event, took almost another generation. When it was done, even the percentage of well known compounds was different. The data themselves had changed. That is the last of the senses in which we may want to say that after a revolution scientists work in a different world.

P140 He refers to a constructivist viewpoint

One by one, in a process often compared to the addition of bricks to a building, scientists have added another fact, concept, law, or theory to the body of information supplied in the contemporary science text.

P146 Criticism of Bayesian approaches

As a result, probabilistic theories disguise the verification situation as much as they illuminate it. Though that situation does, as they insist, depend upon the comparison of theories and of much widespread evidence, the theories and observations at issue are always closely related to ones already in existence. Verification is like natural selection: it picks out the most viable among the actual alternatives in a particular historical situation.

P151 Darwin, in a particularly perceptive passage at the end of his Origin of Species, wrote: "Although I am fully convinced of the truth of the views given in this volume…, I by no means expect to convince experienced naturalists whose minds are stocked with a multitude of facts all viewed, during a long course of years, from a point of view directly opposite to mine. … [B]ut I look with confidence to the future to young and rising naturalists, who will be able to view both sides of the question with impartiality."

P152 Still, to say that resistance is inevitable and legitimate, that paradigm change cannot be justified by proof, is not to say that no arguments are relevant or that scientists cannot be persuaded to change their minds. Though a generation is sometimes required to effect the change, scientific communities have again and again been converted to new paradigms.

P172 For many men the abolition of that teleological kind of evolution was the most significant and least palatable of Darwin's suggestions. The Origin of Species recognized no goal set either by God or nature. Instead, natural selection, operating in the given environment and with the actual organisms presently at hand, was responsible for the gradual but steady emergence of more elaborate, further articulated, and vastly more specialized organisms.

P193 Among the few things that we know about it with assurance are: that very different stimuli can produce the same sensations; that the same stimulus can produce very different sensations; and finally, that the route from stimulus to sensation is in part conditioned by education.

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