This paper examines the Timaeus, a metaphysical dialogue of Plato, in an effort to determine the physical underpinnings of morality and rationality. By first analyzing the story of creation and determining the sources of flaws within the universe, this paper focuses on the rational and irrational motions present within the universe. These motions include the divine and ordered revolutions of Reason, but also the chaotic and random motions of Errant Cause. Both of these sources of motion are able to impact the human soul, causing either rational and thus good motion, or disordered and imperfect motion. Ultimately, humans must struggle to maintain rational motions within their souls so that they may be better able to utilize reason.