Saint Thomas Aquinas' Five Proofs for the Existence of God

Saint Thomas Aquinas' Five Proofs for the Existence of God

Scientific reasoning has brought humanity to incredibly high levels of sophistication in all realms of knowledge. For Saint Thomas Aquinas, his passion involved the scientific reasoning of God. The existence, simplicity and will of God are simply a few topics which Aquinas explores in the Summa Theologica. Through arguments entailing these particular topics, Aquinas forms an argument that God has the ability of knowing and willing this particular world of contingent beings. The contrasting nature of necessary beings and contingent beings is at the heart of this debate.

Aquinas sets up this argument in his discussion of whether or not God exists. His five proofs set up the framework for much of his later writings in the Summa Theologica. As with the five proofs in their entirety, most of Aquinas’ reasoning stems from the third proof concerning the existence of God. The first two proofs lead to the third’s conclusion that God is "esse a se", or to be of itself. From this conclusion of God as an infinite being, Aquinas moves to the third question, concerning the simplicity of God. In article four of question three, Aquinas determines that God is ultimately simple in that his essence does not differ from his being. He writes, "Therefore, since in God there is no potentiality, it follows that in Him essence does not differ from being. Therefore, His essence is His being." God is an unchanging, infinite being. There is no conceivable way in which he could have parts, such as a separate being and a separate essence. From these proofs and others, Aquinas determines that God is an all knowing, perfectly good, perfectly powerful being. Moving back to the third proof of the existence of God, Aquinas determines that God is the ultimate being and that his existence precludes the existence of contingent beings. The notion entails the idea that without infinity, finite beings would not exist.

Aquinas also addresses the issue of the simplicity of God. From a series of logical steps, he concludes that God is altogether simple. He says, God is "neither a composition of quantitative parts, since He is not a body; nor composition of form and matter; nor does his nature differ from his suppositum." It only makes logical sense that God, not existing in any physical sense, could not have physica...

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...sary and contingent beings. Evil is not a consequence of the will of God rather it is a lack of good. Aquinas also says that evil in the world is unavoidable. In Question 2, article 3, Aquinas says that God allows evil in order to produce good out of the existence of evil. The existence of evil in the world is indirect. Also, it would seem that God, being all powerful, could eliminate evil in the world but this has not happened. Aquinas reasons this out by discussing the two types of evil, natural and moral. For example, a person dying is often the result of natural events in the community and this person’s death opens up resources for others who are still alive. The sense of competition in this world adds a sense of necessity to death. There cannot be life without death. This is a similar situation to evil, in that good cannot exist without evil. Natural rules and laws are put into place to make this world, one in which God willed a sense of morals, exist, so natural evil and suffering must exist. With free will, there must be choice. Therefore, evil must exist because human beings make the wrong choices. We are not perfectly good. Things like temptation are part of who we are.