The Structure of Scientific Revolutions | Study Guide

Thomas Kuhn

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The Structure of Scientific Revolutions | Main Ideas



Thomas S. Kuhn does not consistently define the term paradigm. However, his various uses provide a general idea of what he has in mind. It is a model for doing science and a framework within which practitioners do their work. It is a major scientific achievement, a theory that explains nature successfully, and it serves to inform further investigation. Therefore, a paradigm is the framework within which science occurs at a given time and is not questioned by those who work within it.

Normal Science

Normal science is the period of activity during which practitioners solve puzzles or explain previously unexplained phenomena using the existing paradigm. In normal science the paradigm is further articulated, so in a sense, there are no new discoveries and no proposals for new theories. Kuhn calls the process of normal science "mopping up" or "puzzle solving."

During the period of normal science, anomalies, unexplained phenomena for which the paradigm can provide no solution, may be ignored or may even go unnoticed. However, the accumulation of anomalies precipitates a crisis. This leads to a scientific revolution, or paradigm shift. At first practitioners resist the idea the existing paradigm is simply not equipped to address the anomaly.

Scientific Revolution (Paradigm Shift)

When a paradigm fails to address myriad anomalies, a crisis occurs in which scientists begin to work outside the existing paradigm in an attempt to solve the problem. There is likely disagreement over the best solution, partly because factions interpret terms differently—"time," for example, may mean something different from one faction to the next. Eventually, competing theories are more fully articulated and debated. Eventually, through a process that is subjective and even political, enough practitioners convert to a theory, thereby elevating it to the status of paradigm. The previous paradigm is thus displaced.

A paradigm shift signals not only the destruction of a paradigm, it also creates a new way of looking at the world. The practitioners who converted from one paradigm to the next have undergone a "gestalt" shift, in which old observations are new. These observations are different in an important way, just as the duck is significantly different from the rabbit, even though the drawing is of a duck-rabbit. Just as one suddenly sees the duck, or the rabbit, the practitioner is converted by suddenly seeing things differently.

This difference also contributes to the incommensurability of one paradigm with another (lacking common qualities necessary to make a comparison), or one community's practice with another community's practice. For example, trying to compare the smell of a fire to the color red is virtually impossible. They are so different in nature as to be indescribable. However, because scientists no longer share the same concepts and language, it does not mean they cannot communicate. Nonetheless, it would be a mistake to think the paradigm shift is a building of one theory on top of another.

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