Paradigm comes from Greek παράδειγμα (paradeigma); "pattern, example, sample";[1] from the verb παραδείκνυμι (paradeiknumi); "exhibit, represent, expose";[2] and that from παρά (para); "beside, beyond";[3] and δείκνυμι (deiknumi); "to show, to point out".[4]
In classical (Greek-based) rhetoric, a paradeigma aims to provide an audience with an illustration of a similar occurrence.
The Oxford Dictionary of Philosophy (2008) attributes the following description of the term in the history and philosophy of science to Thomas Kuhn's 1962 work The Structure of Scientific Revolutions:
Kuhn suggests that certain scientific works, such as Newton's Principia or John Dalton's New System of Chemical Philosophy (1808), provide an open-ended resource: a framework of concepts, results, and procedures within which subsequent work is structured. Normal science proceeds within such a framework or paradigm. A paradigm does not impose a rigid or mechanical approach, but can be taken more or less creatively and flexibly.[10]
Incommensurability
Kuhn pointed out that it could be difficult to assess whether a particular paradigm shift had actually led to progress, in the sense of explaining more facts, explaining more important facts, or providing better explanations, because the understanding of "more important", "better", etc. changed with the paradigm. The two versions of reality are thus incommensurable.
Kuhn's version of incommensurability has an important psychological dimension. This is apparent from his analogy between a paradigm shift and the flip-over involved in some optical illusions.[16] However, he subsequently diluted his commitment to incommensurability considerably, partly in the light of other studies of scientific development that did not involve revolutionary change.[24]
One of the examples of incommensurability that Kuhn used was the change in the style of chemical investigations that followed the work of Lavoisier on atomic theory in the late 18th century.[16] In this change, the focus had shifted from the bulk properties of matter (such as hardness, colour, reactivity, etc.) to studies of atomic weights and quantitative studies of reactions. He suggested that it was impossible to make the comparison needed to judge which body of knowledge was better or more advanced. However, this change in research style (and paradigm) eventually (after more than a century) led to a theory of atomic structure that accounts well for the bulk properties of matter; see, for example, Brady's General Chemistry.[25] According to P J Smith, this ability of science to back off, move sideways, and then advance is characteristic of the natural sciences,[26] but contrasts with the position in some social sciences, notably economics.[27]
This apparent ability does not guarantee that the account is veridical at any one time, of course, and most modern philosophers of science are fallibilists. However, members of other disciplines do see the issue of incommensurability as a much greater obstacle to evaluations of "progress"; see, for example, Martin Slattery's Key Ideas in Sociology.[28][29]