Method and the a priori in Keplerian metaphysics

International audienc

I will analyze how a natural philosopher, according to Johannes Kepler (1571-1630), can move from phenomena to knowledge of a priori causes, those causes included in the divine “idea” of the world. By doing so, I hope to enlarge upon recent studies that discuss the influence of regressus-style logic on Kepler’s natural philosophy. The first part of this article will focus on Kepler’s influences at Tübingen and on the preface to the first edition of the Mysterium Cosmographicum (1596). The preface is an important document. In it, Kepler presents his own narrative of discovery. In the second half of the article, I will jump to his last a priori works, those published around 1620. I will argue that these add a level of detail and precision to the a priori method first presented in the Mysterium. I will end by considering the 1621 edition of the Mysterium, showing how Kepler strongly clarifies the limits of geometry in his natural philosophy.