Galileo and the Almagest, c.1589-1592: How Ptolemaic Astronomy Influenced Galileos Early Writings on Motion

This book offers a groundbreaking exploration of Galileo Galileis engagement with the Almagest, Claudius Ptolemys second-century scientific work on the motions of stars and planetary paths. Contrary to the belief that Galileo had little interest in Ptolemaic astronomy, the author investigates whether Ptolemy influenced Galileos shift to Copernicanism, the theory that Earth and all other planets revolve around the Sun. This inquiry is pursued through a detailed examination of Galileos early writings on motion, namely the so-called De motu antiquiora (c. 15891592). By contextualizing Galileos initial reception of Ptolemy, the book reveals a fascinating historical backdrop, highlighting how the Almagest was intended to be read and studied in Galileos milieu during the last decades of the sixteenth century. The author challenges the conventional Ptolemaic-Aristotelian label by showing that early Galileo adhered to a Ptolemaic, yet non-Aristotelian, cosmology supported by an Archimedean-like rationale. Additionally, the book underscores the often-overlooked impact of Theon of Alexandrias commentary on the Almagest in the sixteenth- and seventeenth-century reception of Ptolemy, suggesting it as one of Galileos potential sources. Offering valuable insights for historians of science and early modern astronomy, this book illuminates Galileos intricate relationship with astronomical and philosophical ideas, emphasizing the need to re-examine his intellectual journey within a nuanced historical framework.