The philosopher, the emperor, and mathematics: Michael Psellos’s epistemology of proofs in context

Resumo

This paper explores the epistemology of mathematical proofs in the work of Michael Psellos (1018–1081), a central figure of the Byzantine intellectual milieu in eleventh-century Constantinople. While Psellos is primarily celebrated for his contributions to philosophy, theology, and rhetoric, his engagement with mathematics—especially the epistemological and pedagogical status of proofs—has received little attention. Psellos’s metaphysical commitment to the truth-bearing capacity of logical reasoning situates him within the Neoplatonic tradition, yet his Christian framework imposes limits on the reach of human knowledge. His selective presentation of mathematical reasoning in the De omnifaria doctrina (OD) (Universal Doctrine), a pedagogical work addressed to a young Byzantine nobleman, later ascended to the emperor soil, reveals a deliberate pedagogical strategy: to introduce the future Byzantine emperor to mathematical ideas while deferring their rigorous demonstrations. By distinguishing the epistemic function of proofs (as conveyors of certain knowledge) from their pedagogical function (as staged tools for intellectual formation), Psellos articulates a sophisticated vision of mathematics as both a cognitive and spiritual discipline. This study reconsiders Psellos not merely as a transmitter of ancient knowledge but as a philosopher who reshaped Greek mathematical traditions within a Christian-Neoplatonic synthesis that ultimately contributed to the Neoplatonic revival of the Renaissance.