Jean Buridan

Jean Buridan spent his entire career in the faculty of arts at the University of Paris, teaching logic and working through Aristotle with the rigor of a 14th-century scholastic. Somewhere in that sustained focus he developed the concept of impetus, a way of explaining motion that broke from ancient doctrine and edged toward what would later be called inertia. It was an early crack in the edifice, part of what made the Copernican Revolution possible centuries later. He died around 1359 or 1362, his actual writings preserved but his name now attached most often to a thought experiment about a starving donkey stuck between two bales of hay - a puzzle that never appears in anything he left behind.