L'astronomie nouvelle de Kepler et la logique de la découverte
This thesis offers a study of the theoretical and empirical reasons involved in the elaboration of a new astronomy by Johannes Kepler (1571-1630) as displayed in his work Astronomia nova (1619).  The thesis consists of two parts: the first part deals with Kepler’s actual writings, whereas the second part uses the notion of abduction in order to interpret with logic that process of discovery and justification. The first part begins with an analysis of Kepler’s project and its philosophical, metaphysical and theological foundations as displayed in his first work piece, Mysterium cosmographicum. Then follows a review of Kepler’s own words regarding the nature and status of astronomical hypotheses as proposed through a study of his treatise entitled Apologia pro Tychone contra Ursum. A careful study of philosophical, mathematical and scientific sources that have influenced Kepler for his new astronomy is then proposed prior to a detailed analysis of the scientific arguments and different demonstrative steps that are presented in Astronomia nova.  The second part aims at enlightening the debate on abduction first by looking at three traditional approaches (Plato, Aristote and Epicurus) relative to the scientific knowledge of celestial phenomena that bring about a plausible discourse or a series of explanations that fit with the phenomena. Finally, four modern abductive interpretations of the discovery process followed by Kepler in Astronomia nova are presented, reformulated and reviewed in order to propose a new abductive interpretation that leave a greater place to the actual project of building a new astronomy based on causes. This provides tools to better understand the meaning and significance of what can be understood as the “Keplerian revolution”, namely the transition from a geocentric system to a system not simply heliocentric but heliodynamic, which freed astronomers from the paradigm of circular orbits.
Kepler Abduction Philosophy Astronomy History of science Logic of discovery Kepler Abduction Heliodynamics