Source edition
Aristotle. De animalium motione et De animalium incessu. Jaeger, Werner, editor. Leipzig: Teubner, 1913.
Source data
Open Greek and Latin · CC BY-SA 4.0
Cloned and adapted by Humanitext, with ongoing edits.
Summary
This work is a natural philosophical treatise that investigates the physical, physiological, and psychological mechanisms of locomotion common to all animals. It begins by establishing that for movement to occur, there must be not only internal points of rest, such as joints, but also an absolute "immobile fulcrum" external to the animal, a principle illustrated through an analogy with celestial motion and its unmoved mover. The focus then shifts to the internal psychological origins of movement, analyzing the roles of intellect and desire, and utilizing the practical syllogism to explain how thought leads directly to action. This physiological chain reaction is likened to an automaton, where minute thermal changes near the heart trigger large-scale bodily movements. Finally, the treatise identifies pneuma as the material medium of movement and locates the soul's governing principle in the center of the body, presenting the animal body as an organically ordered state and concluding with an analysis of involuntary movements.