Ancient astronomy described planetary motions with a kinematic approach. Kepler tried
to integrate the dynamic explanation and the concept of force into this approach. His work
functioned as strong proof for heliocentrism. The understanding of Kepler’s three laws,
however, took time. Here, we focus on the origin of the first two laws. We offer our view on
this topic and try to justify it by referring to Kepler’s works, Astronomia Nova and Epitome
Astronomiae Copernicane, and to his letters. We also underline the new elements we introduce
in the debate on Kepler’s dynamics by comparing our interpretation with those provided
in the literature.
