The teaching of astronomy in medieval universities, principally at Paris in the fourteenth century
Richard Lemay (The City University of New York)
Manuscripta, Vol. XX (1976)
When investigating the teaching of astronomy in the medieval universities, a number of considerations must be held in mind. In the first place, it has always to be remembered that medieval astronomy was inextricably involved with Aristotelian cosmological doctrine. The latter postulated a number of ideas about the hier- archy of beings and motions, none of which could be removed with- out the collapse of the entire structure. Aristotle’s system required a First Mover circumscribing the entire universe; below came the several unmoved movers (the heavenly bodies, whose essences or natures were unchangeable) endowed with their own intelligences and transmitting from the First Mover all motion through the ranks of inferior spheres down to the spheres of elements on earth. A quintessence or fifth essence properly belonged to these superior beings and was radically different from the stuff of the four elements on earth; the quintessence required of or drew out from the heavenly bodies and spheres perfection in the circularity of their orbits, as the only qualitative motion befitting their superior natures. The rejection of the Aristotelian concept of a quintessence, which occurred as a result of the work of Copernicus, Galileo and Newton, sounded the death-knell of astrology as a learned discipline.
Once the mysterious influence or attraction between material bodies, especially that emanating from the heavenly bodies, was attributed to their matter, uniform in nature throughout the universe; once variations in attraction were attributed to variations in density of matter and distance of bodies; then attraction or influence could no longer be deemed by the learned a property of superior essence and intelligence. But so long as the Aristotelian cosmology was generally accepted, astrology overwhelmed astronomy in the eyes of men, scientists included.