The most influential thinker of the medieval period, Thomas Aquinas' philosophy combined Aristotelianism and elements of Neo-Platonism within a context of Christian thought. Out of all the writings Aquinas' published, the Summa Theologica incorporates his philosophical system the best. In Thomas Aquinas' most infamous piece of work, Summa Theologica, he formed three major ideas: God, ethics, and Christ, to best illustrate his philosophical system.

The first part of Aquinas' most illustrious work deals with God, who is the starting point, he causes everything and was not caused by anything else. In the most highly recognized question in Part I of the Summa Theologica, Aquinas proved the existence of God in five different ways. He uses Aristotle's beliefs and the basic structure of logic to prove that God is the beginning point, he is the one that caused and created everything else in existence. He is the first mover...