Mathematics and Philosophy at the Turn of the First Millennium: Abbo of Fleury on Calculus (Global Perspectives on the History of Natural Philosophy)

At the turn of the first millennium, scientific and philosophical knowledge was far from dormant.Arithmetic, with its diverse calculation techniques and number theory, served as a bridge to philosophy, theology, and the study of the physical world.Even something as simple as a series of multiplication tables could unlock a profound knowledge of both the divine realm and natural phenomena.Such is the case with Abbo of Fleury’s Commentary on the Calculus. Mathematics and Philosophy at the Turn of the First Millennium sheds light on Abbo’s original philosophical system anchored in two central doctrines, which serve as a compass to navigate it: the theory of unity (henology) and the theory of composition.Yet, the Commentary on the Calculus covers much more.The present study, thus, explores an eclectic range of topics - from water clocks to barleycorns, constellations to human voice, synodic month to the human lifespan, and numbers to God.Abbo’s work is an ambitious attempt to tie together