In his 1377 French translation and exegesis of Aristotle’s On the Heavens, the theologian and natural philosopher Nicole Oresme (c. 1320–1382) challenged the prevailing Aristotelian explanation of celestial motion, which supposed that heavenly spheres required souls or intelligences to move. To explain how the heavens might move with perfect regularity, but without such animating principles, he summoned a technology that had recently become conspicuous in Western Europe—the mechanical clock. In Le livre du ciel et du monde, Oresme writes:

[The movement of the spheres] is somewhat similar to when a man has made a clock and allowed it to run and move by itself. In the same way, God let the heavens be moved continually according to the proportions that the motive forces have with the resistances, and according to the established order (288).[i]