Summa Theologiae is considered one of the most influential books in the field of medieval philosophy and theology. It encompasses various topics connected with Christianity, such as the existence of God, faith and reason, and the goal of human life. This compendium provides reasoning for almost every controversial theme that occurs in Christian doctrine. This essay aims at clarifying the arguments and evidence of St. Aquinas, which support the claim of God’s existence, as well as comparing the Thomistic approach to the views of St. Augustine and St. Anselm.
The matter of God’s existence is a subject of heated debate because even contemporary means of science can neither prove nor debunk this idea. St. Aquinas describes two objections doubting the topic, replies to them, and provides evidence to invalidate the contrary opinion. The first objection states that God does not exist because he symbolizes infinite goodness and would not allow evil to flourish. The second objection says that God cannot be the architect of all events because all-natural things can be attributed to nature, while all voluntary things are a product of human activity and reason.
St. Aquinas attempts to justify five reasons for God’s existence by providing logical explanations. The first argument focuses on the world’s motion and attempts to justify it by tracking the motion cause back to God. Nothing can move by itself because motion is gained by one object giving momentum to another. This argument implies that God is the original source that provides enough force for the world to gain momentum. The second reason is the nature of efficient causes: nothing can be a cause of itself; therefore, the original cause must be God’s work. The third answer is centered on the world’s creation and argues that if nothing existed in the first place, it wouldn’t be able to reproduce, grow and die; therefore, the original creator is the Lord. The fourth reason focuses on gradation: there are always more and less good, virtuous, noble personalities in this world; therefore, something representing absolute goodness and perfection must be God. The fifth argument focuses on non-intelligent beings that somehow achieve the desired end-results, so they must be guided by God.
The views of St. Augustine of Hippo have some similarities to the views of St. Aquinas. Early church fathers did not see the necessity of proving God’s existence; therefore, they did not form any ontological arguments. However, St. Augustine’s interpretation of the nature of God coincides with that of Thomas Aquinas. The former saw God as something eternal that governs the whole world by motion and change and exists outside of time and space boundaries.
It is also worth mentioning that in the process of making his reasons for God’s existence, St. Aquinas objected to one of the earliest ontological arguments made by St. Anselm of Canterbury. Even though two scholars tried to prove God’s existence, they utilized different means to achieve their goals. St. Anselm argued that God is an idea in the mind of mortals, and, since humanity cannot imagine anything greater than the Lord, God exists. However, St. Aquinas believed that the human mind could not comprehend the complexity of God’s nature; hence, he considered the argument invalid.
In conclusion, Summa Theologiae provided a new ontological argument that analyzes the matter from philosophical and theological viewpoints. St. Aquinas’ interpretation of God’s nature correlates with early church fathers’ studies, which he incorporated to form five reasons for God’s existence. Every piece of evidence that St. Aquinas utilized could be considered credible in Medieval; however, contemporary science makes his assumptions very questionable. Nevertheless, the significance of this new approach to God’s existence cannot be underestimated since it provided new arguments to support the claim and objected to the existing ones.