born 1300, Béthune?, France
died 1358
French philosopher, logician, and scientific theorist.
He studied under William of Ockham at the University of Paris and later taught there. According to his modified version of determinism , though one must choose what presents itself as the greater good, the will is free to delay reason's judgment by suggesting a more thorough inquiry into the worth of one's motives. The dilemma of a particular kind of moral choice, between two evidently identical alternatives, is illustrated by the celebrated allegory of "Buridan's ass." Among his achievements in mechanics was a revision of Aristotle 's theory of motion; he developed a theory of impetus by which the mover imparts to the moved a power, proportional to the former's speed and mass, which keeps it moving. His studies of optical images prefigured modern developments in cinematics. In logic he explicated the doctrines of Aristotle and Peter of Spain ( 0441; 121077). His works include Summula de dialecta (1487) and Consequentie (1493).