Some intertheoretic relations between ptolemean and Copernican astronomy

Abstract

Since the appearance of Thomas Kuhn's books on the Copernican Revolution and the Structure of Scientific Revolutions, the displacement of ancient astronomy by Copernican has gained renewed interest among philosophers of science. For Kuhn the Copernican revolution is something like a 'paradigm' of a scientific revolution. Hardly any other episode from the history of science is more frequently used by him to illustrate his major points. But it seems to be the case that the Copernican revolution itself cannot be very adequately accounted for by some of his general observations and conclusions. For Kuhn the distinction between context of discovery and context of justification ceases to make sense or is at best a questionable dichotomy. As a result, the status of the internal and external approach to the history of science changes to a considerable extent. Kuhn does not aim at a systematic and complete separation of these two aspects, but rather considers their amalgamation one of the most important goals of the historiography of science.2 As far as I can see, there are at least three alternatives to this point of view: for many historians, the conditions which make internal relations between scientific theories at all possible did not arise prior to the emergence of modern science.3 For these historians, it is only natural then, that in general one cannot find a purely internal relation between Ptolemean and Copernican astronomy, which could be sufficient to justify the choice of the Copernican theory as rational. The other points of view are well known: for some, the history of science can ultimately be explained only externally, for others, the history of science is also a rational process and is therefore internally reconstruc? tible. For many, a rational reconstruction of history seems to be a futile