In the celestial physics presented in his New Astronomy, Kepler explains the planetary motions through the action of the solar motive force or power. In regard of the approximation, performed in the book, between celestial physics and explanations grounded upon "corporeal forces", the numerous moments when Kepler resources to the notions of planetary souls and minds are somehow striking. In the present article we discuss these underestimated extracts from the New Astronomy, where Kepler employs the notions of planetary minds and souls. Intending to enlighten the subject, we have dealt in the second section with the definition of Earth's soul drawn by Kepler in his work on the regular shape of snowflakes, written right after the publication of the New Astronomy. Kepler ascribes the hexagonal shape of snowflakes to a certain forming faculty of the Earth's soul, which would act as a geometrizing power with the aim of optimizing the heat's departure during the freezing process.
Kepler; physical astronomy; snowflakes; soul; mind