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reviewed: 6/95 The Structure of Scientific Revolutions, 2d ed. Thomas S. Kuhn. University of Chicago Press (1970). $9.95 pb.

In the absence of a paradigm ... early fact gathering is a far more nearly random activity than the one subsequent scientific development makes familiar.
---T.S. Kuhn

If you have been involved in teaching or researching the history and nature of science, you are probably familiar with references to Thomas Kuhn. His work has altered our view of the nature of science. For example, when James Rutherford and Andrew Ahlgren wrote about revolutions in science for Project 2061's Science for All Americans, they were illustrating a viewpoint proposed by Kuhn. The National Science Education Standards also makes a distinction between revolutions in science and changes that occur as small modifications of extant knowledge. When we see the phrase "paradigm shift" in educational literature, we again encounter the influence of Kuhn's work. As it happens, this phrase is used often and misused often. If you have not read this classic work, or have not read it in a few years, it is worth examining for the richness of examples that Kuhn provides. The second edition is particularly interesting because Kuhn wrote a postscript on the uses and misuses of the phrase "paradigm shift."

In The Structure of Scientific Revolutions, Kuhn describes the scientific method presented in textbooks as a misrepresentation of the scientific enterprise. Textbooks typically portray the scientific enterprise as one in which knowledge changes gradually as more information accumulates. If we were to accept the model of science by accumulation, Kuhn argues, we would be forced into one of two conclusions. Either (1) errors and myths can result from careful observation, because we no longer accept some scientific explanations as valid (such as the phlogiston theory), or (2) these discredited theories were scientific, but are incompatible with the beliefs we hold today. Kuhn argues that historians of science must accept the second conclusion. In setting the stage to debunk science by accumulation as the only model, Kuhn defines and uses the phrase "paradigm shift," which has since become widely used in educational literature.

A paradigm is a theory that explains a collection of observations sufficiently well to unite a group of researchers. Furthermore, normal science cannot proceed without a paradigm or an agreed-upon explanation. Kuhn defines normal science as work that proceeds in accord with the paradigm or guiding idea. In teaching, we make use of guiding ideas when we consider the context of an investigation. Consider the example of students whose project is a field study of how raccoons survive in a variety of environments. In this ecological field study example, our knowledge of the theory of evolution would influence both the questions we posed for students and how we interpreted the results of their study. The theory of evolution would be the paradigm.

A paradigm sets the stage for the type of questions people ask. Kuhn groups normal scientific research into three categories: (1) attempts to increase the scope and accuracy by which facts are known (these are facts the paradigm has made worth knowing with more precision and in a greater variety of situations--such as structural formulas of molecules); (2) facts that can be compared with predictions from the paradigm (such as special telescopes to demonstrate the Copernican prediction of annual parallax); and (3) applying the paradigm to new situations to further articulate the theory and clarify ambiguities (such as Hertz's work in the nineteenth century that expanded Newton's Principia).

A paradigm shift begins to occur when the data no longer support the extant paradigm. In other words, if a theory is applied to a new situation and does not accurately predict results, the data must be re-evaluated and reconsidered. Kuhn shows that a community of scientists does not readily give up an accepted theory. For example, Kuhn argues that to ask, "on what date was oxygen discovered?," is ahistoric because the paradigm shift occurs over the course of years and is almost never the work of a single person. To use the example of oxygen, the researcher whose work revealed the existence of oxygen was not looking for oxygen, but attempting to answer a question that resulted from phlogiston theory. Kuhn argues that historians of science must not pursue a linear view that relates to our current theories, but consider a researcher in the context of his or her time. For example, in researching Galileo, one might consider what beliefs he had about the influence of the stars.

Kuhn's work is also significant to educators because of the use he makes of the work of Jean Piaget. For those who are interested in constructivism, here is a sample quote: "...a new theory, however special its range of application, is seldom or never just an increment to what is already known. Its assimilation requires the reconstruction of prior theory and the re-evaluation of prior fact, an intrinsically revolutionary process..." (p.7). Kuhn, like Piaget, is explaining a theory about how people acquire and transform knowledge. Reading this book provides an opportunity for teachers to reflect on the transformations they see as their students acquire new information that is difficult to assimilate into their previous models of the way the world works.

If you prefer to look at examples and focus on case studies, you might begin with Chapter 10, "Revolutions as Changes of World View." This section contains background on the discovery of Uranus and its labels as star, comet and, finally, planet. Kuhn also describes the works of several eighteenth-century chemists and the development of atomic theory. (To further your case study base, you might also see I.B. Cohen's History of Scientific Revolutions.)

In summary, Kuhn's text is not only a rich source of ideas, but also an impressive assemblage of facts. Whether you are searching for case studies or for a rigorously intellectual philosophy text, this book still deserves a place on your reading list.

--Mary McMullin

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