Cameron F. Coates

This essay discusses the instructional value of mathematical proofs using different interpretations of the analysis cum synthesis method in Apollonius’ Conics as a case study. My argument is informed by Descartes’ complaint about ancient geometers and William Thurston’s discussion on how mathematical understanding is communicated. Three historical frameworks of the analysis/synthesis distinction are used to understand the instructive function of the analysis cum synthesis method: the directional interpretation, the structuralist interpretation, and the phenomenological interpretation. I apply these interpretations to the analysis cum synthesis method in order reveal how the same underlying mathematical activity occurs at different levels of scale: at the level of an individual proof, at the level of a collection of proofs, and at the level of a single line within a proof. On the basis of this investigation, I argue that the instructive value of mathematical proof lies in engendering in the reader the same mathematical activity experienced by the author themselves.