Thomas Aquinas is one of the greatest theologians in history. His Summa Theologica deals with many of the hotly debated topics concerning the nature and dealings of God with humanity. Aquinas discusses Christ assuming a human essence in the fifth part of Part IIIa. The concept of assumption, and the notion of human nature is often not understood by Christians. The phrase “Christ’s assumption of human essence” deserves to be explained in detail. Aquinas, therefore, responds and refutes many objections from his contemporaries. Aquinas, through his use of logic and precise language, disproves that Christ didn’t assume a mind of man. He asserts that Christ assumed a mind of man in order to save mankind.
Aquinas’ arguments are structured to reflect his belief that definitions are essential for understanding theological principles. In his writing, Aquinas spends a great deal of time defining important terms to ensure that his audience understands them. Christ’s assumption does not make an exception. Aquinas uses his entire discussion to define assumption. He claims that it is not possible to “assume an entire body to the unity in nature” and quotes Augustine’s claim that Christ retained his full divinity through the assumption. 3a, q. 5, a. 1, ad. 2). Aquinas argues that assumption does NOT involve the merging of Christ’s nature with man’s. Instead, Aquinas maintains that Christ’s nature and human nature remain distinct. Aquinas views assumption as the act by which a person takes on another nature while maintaining its original nature. Aquinas reaches the conclusion, when it comes to Christ’s human nature, that there are two facets. 5, a. 3, co. 1). A major part of man’s soul is his intellect, which allows him to reason and decide (3a. 5, a. 4, ad. 3). Aquinas answers the claim that Christ was not fully human because he did not have a human brain.
Aquinas reaches three main conclusions in the discussion that precedes the topic: Jesus assumed a body real, Christ’s body human was a physical body, and Christ assumed also a soul human (3a, Q. 5, a. 1-3). This section is devoted to the soul. It examines whether Christ assumed an entire human soul, or if the intellect was omitted. Jesus not having a brain stem is the main objection to this idea. Christ has the wisdom from God and does not need it. 5, a. 4, arg. 1). God, as well as Jesus, is omniscient. Aquinas opponents believe that it’s logical for Christ to assume a human form, since God doesn’t have a physical body. For them, however, it is not logical that Christ would assume finite capacity and a limited mind, when he has already known everything. Aquinas’ response to the argument argues that it is not only logical and imperative, but necessary for Christ to assume a mind of a man.
Aquinas believed that Christ assumed the entire soul of a man because it is implied in the Bible. Many of Jesus’s actions in the Gospels are indicative of human intelligence. Luke says that Jesus grew in stature and wisdom, but a God who knows everything cannot grow more wise. (Holy Bible Luke 2:52). Aquinas uses a similar example to prove that Christ had a human intelligence. Matthew says that Christ was amazed at the faith shown by the Roman officer in Matthew 8:10. Christ is amazed by this encounter because he “see[s] the effect but [is] ignorant of the cause” (S.T. 3a, q. 5, a. 4, arg. 1). Christ’s divine nature cannot account for the officer’s response. Christ would, as a deity, know what led him to have such faith in that particular moment. Christ can only marvel if he is finite.
Aquinas rejects this idea as well, because it contradicts the truth of Incarnation (3a. 5, a. 4, arg. 1). The term “incarnation”, in this context, refers to the process by which one becomes flesh. Flesh doesn’t refer only to the physical body. It also means “the entire person” (3a.q. 5, a. 3, ad. 1). This synecdoche uses the word flesh to describe the entire human nature. It includes both the body and soul. On this basis, it is impossible to have flesh if you do not also have a body. Christ, as stated in John’s Gospel, assumed both a human body (John 1:14) and a person soul. Aquinas says that the part of the human spirit that is unique to man is his rationality. 5, a. 4, arg. 1). The mind being the distinguishing feature of the soul of man, it was essential that Christ assumed a human mind when he assumed human nature. Jesus would cease to exist “in human flesh” if he did not possess a mind.
Incarnation is evidence of Christ’s assumption of a human brain. It is also one reason why it happened. Aquinas believed that the Incarnation’s purpose was to “justify man from sin”. 5, a. 4, arg. 1). Aquinas, too, quotes Damascene when he says that “what wasn’t assumed isn’t curable” (3a. 5, a. 4, arg. 1). Jesus assumed the human nature in order to live an unblemished life and to die for the crimes committed by humanity while he was flesh. Christ’s righteous acts in each aspect of the human being cover sins. Aquinas states that “the soul of man is incapable of sin… except through the intellect” (3a.q. 5, a. 4, arg. 1). Aquinas seems to believe that the soul does not sin by itself, but rather that the mind is what allows the soul to sin. Man’s mind is where he can reason and use his free will. Through this, he is able choose to sin. People who claim that Jesus was not a man suggest that Christ’s sacrifice wasn’t justified by the human mind. If that is the case, then the part of the mind that has the freedom to sin would not have been made righteous in Christ’s death. God’s grace will not cover our minds, but we would still be judged on God’s standards. Man’s imperfect mind would condemn him. The Incarnation’s purpose would be unfulfilled, as mankind would remain separated from God because of sin. Aquinas rejects the claim because his understanding is incompatible.
This question of whether Jesus assumed human mentality is part of a larger discussion about human nature, Incarnation and salvation. Aquinas views the Bible not only as a source of God’s knowledge, but also as a basis for his theological discussions. He uses Scripture to support arguments that are then developed by reason. Aquinas, in this particular passage of the Summa Theologica argues that Christ assumed true human nature and implicitly affirms the goodness inherent to human nature. Aquinas, by showing that Christ was a man, validates his work in theology. Aquinas, empowered by God’s Grace and the Holy spirit, can also use his mind in order to bring glory to God. Aquinas helps us to understand God’s nature and his relationship to humanity.
