The
Oxford English Dictionary defines a
paradigm as "a pattern or model, an exemplar; a typical instance of something, an example". The historian of science
Thomas Kuhn gave the word its contemporary meaning when he adopted the word to refer to the set of concepts and practices that define a scientific discipline at any particular period of
time. In his book,
The Structure of Scientific Revolutions (first published in 1962), Kuhn defines a scientific paradigm as: "universally recognized scientific achievements that, for a time, provide model problems and solutions to a community of practitioners, i.e., •
what is to be observed and scrutinized • the kind of
questions that are supposed to be asked and probed for answers in relation to this subject •
how these questions are to be structured •
what predictions made by the primary theory within the discipline •
how the results of scientific investigations should be interpreted •
how an experiment is to be conducted, and
what equipment is available to conduct the experiment. In
The Structure of Scientific Revolutions, Kuhn saw the sciences as going through alternating periods of
normal science, when an existing model of reality dominates a protracted period of puzzle-solving, and
revolution, when the model of reality itself undergoes sudden drastic change. Paradigms have two aspects. Firstly, within normal science, the term refers to the set of exemplary experiments that are likely to be copied or emulated. Secondly, underpinning this set of exemplars are shared preconceptions, made prior to – and conditioning – the collection of evidence. These preconceptions embody both hidden assumptions and elements that Kuhn describes as quasi-metaphysical. The interpretations of the paradigm may vary among individual scientists. Kuhn was at pains to point out that the rationale for the choice of exemplars is a specific way of viewing reality: that view and the status of "exemplar" are mutually reinforcing. For well-integrated members of a particular discipline, its paradigm is so convincing that it normally renders even the possibility of alternatives unconvincing and counter-intuitive. Such a paradigm is
opaque, appearing to be a direct view of the bedrock of reality itself, and obscuring the possibility that there might be other, alternative imageries hidden behind it. The conviction that the current paradigm
is reality tends to disqualify evidence that might undermine the paradigm itself; this in turn leads to a build-up of unreconciled anomalies. It is the latter that is responsible for the eventual revolutionary overthrow of the incumbent paradigm, and its replacement by a new one. Drawing on
N. R. Hanson's discussion of
theory-ladenness, Kuhn used the expression
paradigm shift (see below) for this process, and likened it to the perceptual change that occurs when our interpretation of an ambiguous image "flips over" from one state to another. (The
rabbit-duck illusion is an example: it is not possible to see both the rabbit and the duck simultaneously.) This is significant in relation to the issue of
incommensurability (see below).
worldviews (and see below),
ideologies, and
mindsets. They have somewhat similar meanings that apply to smaller and larger scale examples of disciplined thought. In addition,
Michel Foucault used the terms
episteme and
discourse, mathesis, and taxinomia, for aspects of a "paradigm" in Kuhn's original sense. == Paradigm shifts ==