Twelfth Century Philosophical Dichotomies

Murdoch, John E. Antiquity and the Middle Ages. 1St edition, New York: MacMillan Publishing Company., 1984.

"Divisio scientarum II" Murdoch p. 40

MS BL Egert 935, fol. 36r

philosophy (summa disciplina) divided into physica (arithmetic, geometry, astronomy, music ** also medicine, astrology, mechanics), ethica (prudence, justice, fortitude, temperance), and loyca (grammar, dialectic, rhetoric)

Note this isn't a perfect hierarchy - physica separates out into arithmetic, geometry, astronomy, music, medicine, astrology, and then recombines at mechanics. Why?