On the Nature of Force and Weight
Aphorisms defining force as an invisible spiritual power, set against corporeal weight
This text-only sheet gathers Leonardo's definitions and aphorisms on force (forza) and weight (peso), written in his mirror script with no diagrams. In the opening passage and the right-hand column he defines force as a spiritual, invisible power infused by violence into bodies driven from their natural state, always striving furiously toward its own extinction. The left-hand column treats weight as its corporeal, material counterpart, which seeks its resting place, and the two are described as opposites that generate and overcome one another.
On this page
Force as an invisible spiritual power
Force is defined as entire throughout itself and entire in every part of itself. It is a spiritual virtue, an invisible power infused by accidental violence into all bodies held outside their natural inclination, giving them a semblance of life as it compels and transforms them and runs toward its own undoing.
Aphorisms on force (right column)
A column of short maxims: slowness makes force great and quickness makes it weak; it lives by violence and dies by freedom; it transmutes and compels every body to change place and form; nothing moves and no sound is heard without it, and its true seed lies in sensible bodies.
Weight against force (left column)
Weight is entire in the whole of its perpendicular opposition and passes by nature toward its desired place. Weight is corporeal, material and reluctant to move; force is incorporeal, spiritual and always fleeing. The two often generate and overcome one another, and if of equal temper keep long company.
