Thomas Aquinas (1225-1274) was a renowned catholic theologian who proved God’s existence in five different ways. In his first cause, which was his second proof of God’s existence, he elaborated that whatever belongs to a being is a result of the ethics of nature. He also explained that what belongs to a thing is caused by its quiddity or essence. Anything that does not belong to the principle of quiddity or form comes from without. According to him, it was impossible that existence resulted from a thing’s quiddity, form, or by an efficient cause. This is because, if this could be the case, then things would be in existence due to their own cause, which is impossible. Therefore things cannot bring themselves to existence but can exist as a result of nature. Considering that each creature has a reason for existence, there must be some being that is the cause of all existence. This being is superior since it controls the existence of all things, and no other creature can match the being who is God.
In his argument, Aquinas made it clear that something would not be the cause of itself coming into existence. He stated that if something does not exist due to nature, there must be something else resulting in existence. He concluded that it was impossible for anything to exist on its own, and, in his first cause, he stated that the world had sensible things organized in efficient causes (Gallagher, 2018). Therefore, a thing cannot be an efficient cause on its own because it would exist before itself, which is impossible. Aquinas, therefore, believed that it was necessary admitting that the first efficient cause to everybody is God.
Negative predication refers to excluding a concept from something or considering non-existent something that has been mentioned in a particular approach. The negation is usually a statement that does not necessarily mean being or non-being but is an overview of an individual’s opinion. For example, in proving God’s existence, Aquinas stated that individuals could not grasp the nature of God in itself. This was a negative predication because the statement is a negation about God’s nature. The predication meant that human beings have a limit in knowing God’s actions and why He acts the way He does. Comprehending God’s nature through knowing His characteristics, traits and divinity is not enough to know thoroughly about Him. Analogical predication is defined as what human beings for sure know about God. For example, when Aquinas explained that we only grasp the nature of God from the effects seen in creatures, this was an analogical predication. The predication meant that human beings could know God after seeing His actions on others. Therefore, God’s actions upon individuals are a true reflection of who He is, and no one can alter His being. This predication touches on facts about God’s relationship to His creatures which provides evidence of his divinity.
Reference means an action of mentioning or even alluding to something. For example, in the negative and analogical predications, Aquinas refers to God. He defines God’s nature as that which can be revealed through His relationship with Human beings. In his explanation, Aquinas refers to God as having effects on His creatures, which is how human beings can learn about his characteristics. He also explains that it is impossible for human beings to exist on their own cause as God is the superior being in charge of overall existence. In his arguments, Aquinas alludes to God defining Him as superior and the reason behind everyone’s existence.
According to St. Thomas, in one way, the word “being” denotes the act of being. He further explains that the act of existence results from an efficient cause and that individuals cannot exist on their own. Things can exist as a result of nature or something else. Therefore the act of individuals existing on their own is impossible, and according to Aquinas, existence from a thing’s quiddity or essence is unmanageable as individuals cannot bring themselves to being. He is clear on human beings’ existence and concludes that no creature can match God’s ability to bring individuals to being as he is supernatural. With this explanation, human beings cannot know the being of God. The same way individuals cannot comprehend his essence.
On his second expression of “being,” Aquinas is categorical on its definition as the composition of a subject. He expounds that this is the only way human beings can know about God’s nature, characteristics and traits. Individuals can have proof of God’s existence from his effects upon people. The relationship between God and people helps human beings identify his characteristics since knowing him without any proof of existence is impossible. Therefore, it is possible to distinguish the presence of God through the way He manifests Himself to people in their daily undertakings. Individuals have limits in knowing about the nature of God and His divinity and can only comprehend existence through others.

Gallagher, D. M. (Ed.). (2018). Thomas Aquinas and his legacy. CUA Press.