Kuhn and paradigm shifts

Thomas S. Kuhn, an American historian of science, has proven very influential in the philosophy of science, and is often connected with what has been called postpositivism or postempiricism. In The Structure of Scientific Revolutions , Kuhn divided the process of doing science into two different endeavors, which he called normal science and extraordinary science (which he sometimes also called revolutionary science ). The process of "normal" science is what most scientists do while working within what he calls the current accepted paradigm of the scientific community, and within this context Karl Popper's ideas on falsification as well as the idea of a scientific method still have some currency. This sort of work is what Kuhn calls "problem solving": working within the bounds of the current theory and its implications for what sorts of experiments should or should not be fruitful. However, during the process of doing "normal" science, Kuhn claimed, anomalies are generated, some of which lead to an extension of the dominant "paradigm" in order to explain them, and others for which no satisfactory explanation can be found within the current model. When enough of these anomalies have accumulated, and scientists within the field find them significant (often a very subjective judgment), a "crisis period" is begun, Kuhn argues, and some scientists begin to participate in the activity of "extraordinary" science. In this phase, it is recognized that the old model is fundamentally flawed and cannot be adapted to further use, and totally new (or often old and abandoned) ideas are looked at, most of which will be failures. But during this time, a new "paradigm" is created, and after a protracted period of ‘paradigm shift' the new paradigm is accepted as the norm by the scientific community and integrated into their previous work, and the old paradigm is banished to the history books. The classic example of this is the shift from Maxwellian/Newtonian physics to Einsteinian/Quantum physics in the early 20 th century. If the acceptance or failure of scientific theories relied only on simple falsification, according to Kuhn, then no theory would ever survive long enough to be fruitful, as all theories contain anomalies.

The process by which Kuhn said a new paradigm is accepted by the scientific community at large does indicate one possible demarcation between science and pseudoscience, while rejecting Popper's simple model of falsification. Kuhn instead argued that a new paradigm is accepted mainly because it has a superior ability to solve problems that arise in the process of doing normal science. That is, the value of a scientific paradigm is its predictive power and its ability to suggest solutions to new problems while continuing to satisfy all of the problems solved by the paradigm that it replaces. Pseudoscience can then be defined by a failure to provide explanations within such a paradigm.