Thomas Aquinas argued that, while revelation alone can supply knowledge of the divine nature, unaided human reason can infer the divine existence from the world's existence. His proofs of God's existence are, in principle, extensions and elaborations of the patristic natural theologies. The Fathers believed that Neoplatonic and Hellenistic speculations about the eternal One, the arche of the cosmos, constituted a ‘natural’ knowledge of God the Father and his creation. God's selfrevelation in the incarnation was placed in the context of this natural theology. Augustine's version of natural theology both summed up the patristic achievement for the West and laid the foundation for Western medieval exploration of the natural knowledge of God. Like Augustine, Thomas believed one could reason naturally from the sensible world to God's existence; unlike him, Thomas reasoned with Aristotle and not Plato. Thomas' ordering of the natural and revealed knowledge of God repeats, then, the patristic sequence: first one proves that God is the first Cause of the world, and then one reasons from revelation about God's redemptive and reconciling relation to the world.
Alvin Plantinga and Thomas Aquinas on the Possibility of Natural Knowledge of God
