Saint Augustine goes from his infantile Christianity to his radical and liberal teenage pursuit of truth which first involves him with the Manichean sect throughout the decade of his twenties. He then leaves that intellectually dissatisfying materialism for a short hiatus in Academic Skepticism which leaves him groping for the transcendent which he found in Plato, the Platonists and faith in God, which then enables him to accept and understand the Catholic faith (Jesus Christ: the Logos Incarnate) and thereby the deepest meaning and good order of the world and the cosmos.
Augustine arrives at the knowledge of God by philosophy and he arrives at knowledge of the world by faith.
He only bridges his skepticism of external reality (phenomena) by faith, the humility of faith and the acceptance of it's concomitant authority.
Cf. Joseph Ratzinger, Augustine Thesis (1951) in Obras Completas, I, Madrid: BAC, 2014, 33-34.
Nisi credideritis, non intelligetis.
Ibid, 46; Cf. De Magistro, 11:37
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