Final answer:
Augustine found more truth in scientific theories than in Manichean theories because they aligned better with his Christian doctrine, emphasis on human free will, and the transient nature of earthly kingdoms compared to the eternal city of God.
Step-by-step explanation:
St. Augustine preferred scientific theories over Manichean theories because he sought to defend Christian orthodoxy by emphasizing that all of God's creation was fundamentally good, in contrast to the dualistic worldview of the Manicheans, who saw the universe as a battleground between equal forces of good and evil. Augustine's perspectives on free will and divine grace also differed from Manichean strict determinism, where he argued for the possibility of human freedom and the ability to choose the good.
Furthermore, Augustine's work during the destabilization of the Roman Empire leaned towards the idea that secular establishments could fail, but the pursuit of Christian faith leading to the heavenly city of God was of ultimate importance. This alignment with emerging Christian thought made him value empirical methods and philosophical reasoning that resonated with Christian teachings, distancing himself from ideologies that contradicted this narrative.