“St. Thomas Aquinas (1225-1274) reconciles the teaching of the Christian Faith with Aristotle’s philosophical principles. Theology uses reason/philosophy to understand the supernatural mysteries of God, Trinity, Incarnation, Grace, Redemption, of revealed Truths first known by believing. Philosophy and theology cannot ultimately contradict each other, since the one, final sources of both truths known by unassisted reason and truths known by faith is God, who cannot and will not contradict himself. Aquinas argues Five Ways to God’s existence, starting from facts about ordinary experience: I. Anything that changes is moved by something else; an infinite series of movers does not makes sense, so there must finally be an Unmoved Mover. II. When we look at how actual causes work, we see that there must be a First Cause that is God, for only one could possibly [be] the cause of itself. III. Coming to be and passing away (contingency) of beings points to some necessary being, God, as their explanations. IV. When we judge some things to be more perfect than others, we imply the existence of a supremely perfect being as their exemplar and cause. V. Since natural beings tend to operate towards some good end or purpose, there must be an intelligent being by whom every partial good is related to the total good. For Thomas, law is an ordinance of reason for the common good promulgated by one in authority. Eternal law is the intelligibility of the divine nature and essence itself. Divine positive law is law we can only know by divine revelations. Natural law is the intelligibility of the created natural universe knowable by the light of natural reason. Natural positive law are laws by which humans apply the principles of natural law to particular circumstances by enacting human laws” (Frederick Lawrence, Philosophers and Theologians, Boston College).