Abstract

Simplicius, writing in the sixth century, distinguishes physical science from astronomy on the ground that, whereas it is the function of the physicist to “inquire into the nature of the heavens and the stars, into their potentialities, their quality, their becoming and passing away,” astronomy has no competence in questions of this primary character. Its function is “to determine the order of the heavenly bodies, their figures, magnitudes, distances from the earth, sun and moon, their eclipses, conjunctions, the quantitative and qualitative properties of their motions,” etc. For this purpose it requires arithmetic and geometry, but cares not how the heavenly motions be described, whether in terms of excentrics or epicycles, so long as the appearances can thus be accounted for.