Bonaventura Cavalieri

Bonaventura Francesco Cavalieri was born in 1598 and took vows as a Jesuate, a now-extinct religious order that blended devotion with scholarship. His mathematics broke ground on optics and motion, but the lever was his work on indivisibles: the idea that a figure could be treated as an infinite stack of lines or planes, each with no thickness. The principle that bears his name — comparing solids by comparing their cross-sections — gave geometers a powerful shortcut and foreshadowed the integral calculus Newton and Leibniz would formalize decades later. He also brought logarithms across the Al…