Utilitas astronomiae in the Renaissance: The Rhetoric and Epistemology of Astronomy

This essay will consider the views of several prominent Renaissance scholars regarding the practical embedment of astronomy. Certain rhetorical commonplaces are frequently returned to in their writings, in works related to the utilitas astronomiae (astronomy's utility). Such texts can be grouped within the Renaissance genre of the encomia scientiarum et artium, and include rhetorical pieces from the Averroist philosopher Girolamo Fracastoro (1478-1553) in his Homocentrica (1538), the Wittenberg ephemerist Erasmus Reinhold (1511-1553) in the dedicatory letter of his edition of Ptolemy's Almagest (1549), the renowned Jesuit mathematician Christophorus Clavius (1537-1612) in the preface to his commented edition of Sacrobosco's De sphaera (1570), and the Scottish mathematician Duncan Liddel (1561-1613) in a eulogy on mathematics delivered at Helmstedt in 1591. According to these sources, the practical realms benefiting from astronomy ranged from navigation and agriculture, to medicine, pedagogy, theology, and even civil affairs, where the discipline was relied upon, for instance, in the computation of calendars to schedule religious festivities. In his Scholae mathematicae (1569), the Paris lecteur royale Petrus Ramus (1515-1572) turned the treatment of the utility of mathematics into a reflection on the practical origins of science in general. Particular attention is devoted to Girolamo Cardano (1501-1586) as a scholar committed to an empirical and practical conception of knowledge. According to him, astronomy had a range of practical uses, whether in navigation or medicine, or even in the prediction of future events by means of astrology. His Encomium astrologiae (1543) is compared with his other eulogies concerning mathematical sciences and the arts, and with small tracts in which he developed a sort of epistemology of practical knowledge.