Aquinas was influenced by the writings of Aristotle , the Muslim Aristotelians Averro s and Avicenna, and the Jewish philosopher Maimonides. Unlike many theologians, he welcomed the Latin translation of Aristotle's complete writings. Aquinas meant to take Aristotle's philosophical arguments to their deepest level, not just to fit them into the existing theological framework. He pressed the distinction between potentiality and actuality and defended immortality without diminishing the doctrine that the soul is embodied. His definition of philosophical disciplines starts with logic, which are the mental constructions we place on our experience.
Moral philosophy studies personal ethics, economics, and politics.
Aquinas insisted that the truths of faith and those of sense experience, as presented by Aristotle, are fully compatible and complementary. All knowledge, Aquinas held, originates in sensation, but sense data can be made intelligible only by the action of the intellect, which elevates thought toward the apprehension of such immaterial realities as the human soul, the angels, and God. To reach understanding of the highest truths, those with which religion is concerned, the aid of revelation is needed. Aquinas's moderate realism placed the universals firmly in the mind, in opposition to extreme realism, which posited their independence of human thought. He admitted a foundation for universals in existing things, however, in opposition to nominalism and conceptualism.