From philosophy to astronomy: Johannes Kepler and the attainment of the laws of planetary motion
The present work investigates the role played by aprioristic and methaphysical thought in the formulation of scientific and philosophical theories. In the history of astronomy, these ways of approaching a problem have been combined in different ways with empiricism, since it is necessary to confront astronomical theses with observation. In order to better understand how theory can be combined to experience, we studied the way Johannes Kepler, the astrononer, mathematician and philosopher obtained the laws of planetary motion known as the "Three Kepler's laws", combining part of the data previously collected by another great scientist of those times, Tycho Brahe, Coprnican heliocentrism and some mathematical procedures previously developed by Ptolemy. Keplerian theory was based on the astrononer's mathematical and philosophical studies, but his belief on a mathematician God was not enough to support his claims. After collecting new empirical data and reviewing his methods, Kepler as able to, at last, unite theory and observation, physics and astronomy, and this new approach was the essence of the New Astronomy.