Argument · metaphysics · philosophy-of-religion
Aquinas' First Way: The Argument from Motion
Thomas Aquinas' first proof of God's existence, from Summa Theologiae I q.2 a.3. Observed motion (change) is the actualization of potential; nothing actualizes its own potential, and an essentially ordered series of movers cannot regress infinitely, so there must be an unmoved first mover. Includes the Newtonian inertia objection and the infinite-regress challenge.