Summa Theologica Summary

Thomas Aquinas

Summa Theologica

  • Plot overview and analysis written by an experienced literary critic.
  • Full study guide for this title currently under development.
  • To be notified when we launch a full study guide, please contact us.

Summa Theologica Summary

SuperSummary, a modern alternative to SparkNotes and CliffsNotes, offers high-quality study guides that feature detailed chapter summaries and analysis of major themes, characters, quotes, and essay topics.  This one-page guide includes a plot summary and brief analysis of Summa Theologica by Thomas Aquinas.

Thomas Aquinas was a famous theologian of the Middle Ages. His Summa Theologica, written from 1265-1274, is unfinished, but it is still regarded as one of his most significant works. The piece was intended to be an instructional guide to other theology students, but it is much more than that. Summa Theologica answers many questions regarding Western Christianity and its beliefs. To this day, Summa Theologica is one of the foremost authorities on Christianity for theological scholars. Aquinas takes his philosophical and ethical reasoning from Aristotle.

Summa Theologica is divided into three parts. Each part contains more subdivisions. Part one is mostly about God. Aquinas attempts to prove that God exists and answers many questions devoted to the subject. He asserts that the notion that God exists is proof itself that He exists and demonstration of that fact is a possibility, which Aquinas intends to do. He later offers his proofs on God’s existence.

Simply put, objects are in motion at any one given time. These objects are in motion because they were set in motion by something else. When tracing back motions to infinity, the beginner of motion must have been God. He has a similarly argued point about causes and existence. There must have been a beginning of existence and a beginning cause; therefore, God must be the beginning cause and existence.

The world itself has good and bad and somewhere in-between. If there are varying degrees of both, there must be a supreme goodness, which could only be God. Due to Aquinas’s previous arguments, the cause of all things that exist and all things good must also be because of God. In the universe, there are sentient and non-sentient objects, each of which seem to operate for a purpose. It is clear through observance that these objects did not fulfill their purpose by luck or chance, therefore they must be operating under a plan. Whatever guides them, must have some sort of all-knowing and all-powerful intelligence. Obviously, this must be God.

Since Aquinas proved God’s existence in his terms here, he continues by talking about the features of God. God is all-knowing, perfect, omnisciently intelligent, and supremely good. God is also a creator, and Aquinas acknowledges that God created heaven, earth, angels, and demons. He also ultimately created man on the last day of Creation.

Part two of Summa Theologica focuses on man and his purpose on earth. Overall, man’s purpose on earth it to be happy. To be happy, man must follow ethical rules and responsibilities delineated by God. Aquinas acknowledges that perfection by man is unobtainable, therefore it was necessary for God to help in man’s pursuit of perfection, which is why He created Christ. Man is defined by his soul and intellect, which for Aquinas, are one in the same. Intellect is a part of the soul, because reason is inherent within the soul. Despite this, he does recognize that man’s entire existence is not solely based on rationality.

Part two continues by defining man’s intellect. For example, our intellect consists of phantasms, or mental images. When man thinks of a corporeal object, a phantasm develops in his head. Therefore, our intelligence is not just limited to the corporeal. Man is capable of imagining the concept of infinity, but will ultimately be incapable of fully understanding infinity. The mind can figure out cause and effect to a certain extent, which man can then use to try and attempt to understand God on a deeper level.

Reaching happiness is the goal of man, for which he must use his intelligence. Unlike animals, man possesses reason, therefore he must have a purpose for that reason. Happiness, according to Aquinas, does not come from earthly ideas or good. Wealth and fame are irrelevant when it comes to the supreme happiness. Because God is the ultimate good, He is the ultimate source of happiness. Man can only be supremely happy if he fully understands the Divine.

Unfortunately, man is unable to fully understand God until he is one with God, which is in death. Therefore, man’s goal is life is to try and understand the Divine Essence to the best of his ability. It is an imperfect happiness, but by using ethical guidelines and an active effort of will and contemplation, man’s purpose can be ultimately met. Happiness will be awarded to the virtuous in the next life, as it is next to impossible in this life.

Aquinas continues part two by discussing certain virtues and sins. Faith and hope are discussed, along with prudence and temperance. He also discusses gifts often given by the grace of God such as prophecy. Faith and love are ultimately the highest moral principle to ultimately understand and know God. But those two must be in tandem. Perfect love in God is not possible without true faith; man must harness his intellect to understand love to breed faith. After faith is obtained, only then can man truly love God.

The final part of Summa Theologica focuses on Christ. Christ is the mediation between God and man. Man’s potential became perfect within Jesus. All the perfection of faith and love that man could theoretically grasp became possible in Jesus. All of Christ’s sacrifices were necessary to obtain deliverance for man. He ultimately became the bridge allowing God’s forgiveness of mankind’s sins, as His sacrifice came from faith and love.

Aquinas also discusses the sacraments of the church. They are only spiritual because God deemed them to be spiritual, it does not go beyond that. The sacraments are beneficial in helping man receive God’s grace. He also briefly discusses the apocalypse, where nothing will be living, but from that God will build a new heaven and earth. Aquinas touches on many points and ways to reach God’s divinity in his work. To Aquinas, his work summarized the meaning of life through God in all aspects. Although unfinished, his work is prolific.