Source edition
Aristotle. Aristotelis Physica. Ross, W.D., editor. Oxford: Clarendon, 1960.
Source data
Open Greek and Latin · CC BY-SA 4.0
Cloned and adapted by Humanitext, with ongoing edits.
Summary
This work is a philosophical and scientific treatise that investigates the mechanism and ultimate cause of all motion and change. The text begins by establishing the principle that "everything that is moved must be moved by something else," thereby rejecting an infinite regress of motion and proving the existence of a "primary mover." It then argues that the mover and the moved must be in direct physical contact with nothing in between, demonstrating this "being together" across three types of change: locomotion, alteration, and increase or decrease. In the latter part, the discussion focuses on alteration, asserting that true alteration occurs only within the realm of sensible things. The acquisition of bodily or mental dispositions (hexis) and the attainment of knowledge are shown not to be alterations in themselves, but rather accidental changes that accompany sensory alterations. Ultimately, the treatise systematically outlines the causal chain of motion, from immediate physical contact to the primary source of change.