How did Thomas Aquinas combine Aristotelian philosophy with Christian theology?

Thomas Aquinas achieved a landmark synthesis of Aristotelian philosophy and Christian theology by treating them as distinct but complementary domains that could not contradict one another, as both originate from the same divine source.1

Rather than forcing Christian doctrine to align with Aristotelianism, Aquinas modified and corrected Aristotelian principles whenever they clashed with faith. His approach involved:1

• Distinguishing Domains: He separated the methods of philosophy, which relies on sense experience and reason to seek first causes, from theology, which relies on sacred scripture and divine revelation.1
• Conceptual Transformation: He adopted Aristotelian concepts—such as the primary mover and the soul as the form of the body—but deepened them. For instance, he identified Aristotle’s primary mover with the God of Christianity and argued that the human soul, while the form of the body, remains immortal.12
• The Act of Being: He established harmony by reinterpreting the notion of being (esse). He posited that God is pure being, while creatures participate in existence according to their essence, creating a clear distinction between the Creator and the created.1

Aquinas maintained that grace perfects and elevates natural human abilities rather than replacing them, allowing philosophy to serve as a useful instrument for Christian thought.34