Rhetorical uses of mathematical harmonics in Philo and Plutarch

The branch of harmonic science called ‘canonics’ is rarely discussed outside specialist literature in Greek antiquity. Two exceptions are discussed in this paper: one reference to the science and another to its practitioners, both in non-specialist texts (Philo of Alexandria, De opificio mundi 96; Plutarch, Quaestiones convivales iii.9). Because both texts contain erroneous claims given under the authority of canonics, the interpretation of these references is problematic. The two passages are discussed and compared in an attempt to account for the errors contained in them, and to expose the rhetorical aims of each author and the methods by which the technical terms and concepts of an ancient science could be made to serve very different ends in a non-scientific context.