There are three parts to this question: (1) what is a (change of) Kuhnian paradigm,
(2) was the Copernican revolution such a change, and (3) if so, when
did the change take place? To get full marks, you need to address all three: the
first is bookwork, but the second two require you to think for yourself.
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Kuhnian paradigm:
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From the notes, a paradigm is "a well-confirmed and trusted theoretical framework.
Scientists agree on the theory and on an associated set of shared ideas
(e.g. methodology, identification of important problems, etc.)." Note that the
paradigm includes not only the theory, but also the underlying set of shared
ideas and assumptions.
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Therefore, a change of paradigm involves a new theory and a new set of
shared assumptions. Kuhn assumes that such a change will take place after a
crisis, in which the existing paradigm fails to account for experimental
results.
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Was the Copernican revolution a change in paradigm?
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Pre-Copernicus (early 16th century): geocentric solar system, based
on assumption of circular motion;
terrestrial physics does not apply "beyond the Moon"; theories are descriptive
and aim to reproduce (rather than explain) observational phenomena.
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Copernicus (1543): heliocentric solar system, based on assumption of circular motion;
terrestrial physics does not apply "beyond the Moon"; theories are descriptive
and aim to reproduce (rather than explain) observational phenomena.
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Kepler (~1610): heliocentric solar system, based on empirically derived elliptical orbits;
attempts (unsuccessfully) to explain these orbits based on terrestrial physics
(magnetism);
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Newton (1683): approximately heliocentric solar system, based on an inverse square law of
gravity which also describes falling bodies on Earth.
Clearly the start and end of this list correspond to different paradigms, so there was
a paradigm change in here somewhere.
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When did the paradigm change take place?
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Not with Copernicus, despite the name: he has modified the theory but not the
underlying assumptions and methodology (and, as Tycho showed, it is perfectly possible
to recast his model so as to keep the Earth stationary).
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Kepler is starting to change the underlying assumptions, but his theory is still
descriptive (his attempts to turn it into a modern physical theory are unsuccessful).
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Newton's Principia is fully within the new paradigm of universal physical laws.
Since Newton's ideas were very much "in the spirit of the times" (other people, such as
Hooke, were trying similar hypotheses without the necessary mathematical genius to
follow them through), it seems
fair to argue that the paradigm change was actually quite gradual, starting with Kepler
and ending with Newton (though you could reasonably argue that the theoretical basis of
the new paradigm is only fully in place when the Principia is published, and
therefore the paradigm change takes place in 1683).
Note that in the 2007 exam, this question was preceded by one (2b) which asked you to
"Contrast the scientific status of models of the solar system at the beginning and end
of the 17th century." Therefore, candidates attempting this question should have
already had available the material discussed under (2) above. This explains why this
question was only worth 3 marks.
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