Aquinas, Saint Thomas (1225–1274)

Born in Aquino, Italy, Saint Thomas Aquinas was noted for his scholastic synthesis of the philosopher Aristotle and Christian theology. This Dominican monk taught at the University of Paris and was best known for his two “summations” of medieval thought, Summa Theologica and Summa Contra Gentiles, but wrote in many other genres including Bible commentaries, all of which exerted a lasting influence on Christian thought.

Beginning with Boethius, medieval Catholic theologians had disagreed about the concept of time; among Aquinas's important achievements was his sorting out of these arguments. Aquinas's best discussion of time is in the first book of the Summa Theologica, Question 10, which discusses the eternality of God and compares eternity to time. Aquinas brings out six points of inquiry.

First, what is a good definition of eternity? Aquinas bases his definition on one given by Boethius in his De Consol: “Eternity is the simultaneously-whole and perfect possession of interminable life.” Some scholars have stated that the use of the word interminable connotes a negative assessment of eternity. Also, the word life does not match with the ontological definition of eternity. The whole is improper when compared to the simplicity of eternity. Eternity is not instantaneous. The whole and the perfect are redundant. Also, eternity is not a possession. In response, Aquinas appeals to simplicity; for that, human beings must understand eternity by means of time. Time is both being and living. Time is the apprehension of the measuring of movement by the causality of time in the past and the future. Later in the first book, Aquinas saw the existence of time as a measure of duration. Therefore, eternity is the holistic and perfect apprehension of what is outside of movement. We can measure time, because it has a beginning and an end. Eternity is immeasurable. So what is eternal is interminable and has no succession and cannot be possessed.

Second, is God eternal? Some scholars object that because God is the creator of eternity, so he cannot be eternal. God is before and after eternity. One can measure eternity but not God. Time (as past, present, and future) is applied to God in the Bible, although the creeds apply eternality to God. In reply, Aquinas connects time to change, and eternity to immutability. Yet, God is not eternal only; but God is “His own eternity.” For Aquinas, this is a “participated eternity” utilized from scripture through royal metaphors and images of time so that we may understand that eternity is nothing else but God himself.

Third, does eternality belong to God alone? While some see eternality in righteousness, judgment, and necessity, Aquinas said that because God alone is eternal, only God's sharing that eternality with his creation would allow someone or something other than God to be eternal.

[Page 34]Fourth, how does eternity differ from time? Some object to the difference between eternity and time because time is a part of eternity, their natures differ, and eternity swallows up time. Yet, a disagreement may arise because time has a “before” and an “after.” For Aquinas, they are two different things, for eternity has a permanence and time is “a measure of movement: … that eternity is simultaneously whole, but that time is not so.”

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