Galen's computation of medical weeks: Textual emendations, interpretation history, rhetorical and mathematical examinations

Abstract

The seven steps of Galen's unit-fractional computation in On Critical Days, pp. 932.5–933.12 Kühn, which presents corruptions in the manuscript tradition, are here for the first time ever presented in a satisfactorily emended Greek version with English translation. Moreover, this paper provides a survey of the history of scholarly engagement with Galen's computation from antiquity through Syriac, Arabic, Hebrew, and Latin sources to the 17th century. This survey covers, but is not limited to, the medical school of Alexandria, Sergius of Rēšʿaynā, Ḥunayn ibn Isḥāq, Qusṭā ibn Lūqā, Ibn Sīnā, Ibn al-Nafīs, al-Nasawī, Gerard of Cremona, Pietro d'Abano, Niccolò da Reggio, Pierre d'Ailly, Giovanni Pico della Mirandola, Luca Gaurico, Jean Lalamant, Jean Guijon, Giovanni Manardi, Girolamo Cardano, and Antonio Magini. Two further sections are devoted to Galen's Platonizing rhetoric of mathematical accuracy and ten questions that arise from his computation. Thus, Galen's complex motives, his astronomico-mathematical education, his astrological development of a new chronometric concept, the single steps of his computation, and the merits (and limits) of his interpreters are comprehensively elucidated within a perspective including Egyptian, Greek, and Roman mathematics. The results are summarized in the final section. © 2018, Kyoto Sangyo University. All rights reserved.