Abstract
De libero arbitrio presents one of the first arguments of God’s existence developed by a Christian thinker. Using the hierarchy of beings, St. Augustine establishes Reason as an instrument for seeking a reality that is supreme: that which, finding nothing more excellent, Reason itself would not hesitate to call “God”. The present paper demonstrates how this argument is aligned with Augustinian axiom that the rational search already presupposes a fiduciary adhesion. If on the one hand it offers a substrate upon which other thinkers will develop their ontological arguments of divine existence, on the other hand, Augustine differs from them in his intention. For him, more than convincing doubters, this exercise finds its greatest value in strengthening by Reason the convictions of those who have already found, by faith, the God they now seek to know.