Erasmus Reinhold on Copernicus and the “saving of appearances”: A preliminary reassessment

This study offers a preliminary reassessment of Erasmus Reinhold’s role in disseminating Copernican astronomy and his epistemological conception of astronomy’s purpose. While confirming Reinhold as a highly technical astronomer deeply engaged with De revolutionibus , it challenges the view that he was indifferent to cosmological questions. Reinhold praised Copernicus not for heliocentrism itself, but for laying new foundations to revive astronomy, particularly geocentric astronomy. Inspired by Copernicus, he may have envisioned a proto-Tychonic system that rejected celestial spheres without compromising planetary harmony. Unlike Andreas Osiander’s instrumentalist interpretation, Reinhold understood “saving the appearances” as the pursuit of uncovering the true law and harmony underlying planetary motions—a search for the real geometry of the cosmos. Though influenced by an epistemology that privileged mathematics, his concept of harmony was not purely mathematical, as it remained rooted in a geocentric worldview. This reassessment highlights the complexity of Reinhold’s thought and stresses the importance of considering contemporary receptions of his work to better understand his legacy during a pivotal moment in early modern astronomy.