Chapter five concentrates on the Rabbi Moses Maimonides' reformist project to rid Galenism of its Timaean elements. As I establish, while Maimonides' affiliation with Aristotelianism put him in conflict with Galen, the Platonic lines in Galen's thought also generated problems for his own conception of Jewish belief. I show that Maimonides rejected Galen's reading of the Timaeus' cosmogony as heterodox in the Guide for the Perplexed and Medical Aphorisms because of its denial of creation ex nihilo and the omnipotence of God. Therefore, Maimonides had theological reasons for wishing to curtail Galen's philosophical reach. Giving special attention to the Medical Aphorisms, I uncover the various polemical tactics that Maimonides employs, which include giving more limited meanings to Galen's philosophically loaded terminology and mobilizing his own anatomical experience to dispute Galen's brain-centred theory of sensation, to dephilosophize Galenism and recentre it on the body.