Plutarch and the Law of Reflection: Critical and Literary Commentary to De facie 930A-C

Abstract

In 930A-C, Plutarch introduces and immediately rejects the law of reflection because, in his view, the theory is not self-evident nor unanimously accepted. To reinforce this rejection, he provides two examples taken from the field of catoptrics: 1) the images resulting from convex mirrors and 2) those resulting from folding mirrors. Up until now, the slightly corrupted state of the transmitted text and the technical language of the theory and the examples discussed in the passage have prevented scholars from reaching a sound interpretation of the passage. In this paper, I will first address the issues concerning the state of the text, in order to later discuss its problematic content, to wit, whether Plutarch’s rejection of the theory that all reflections occur in equal angles was meant to be taken seriously, as resulting from a confrontation between this theory’s assumptions and reality, or was due to his interest in conveying an ideal image of the moon, a specific interest that could not fit with this theory’s statements.