Thomas Aquinas & the Cosmological Argument

Christian Apologetics and the Infinite Regression

Thomas Aquinas was a Catholic Priest, a Dominican Friar, that lived in Italy in the 13th Century. He was the best and most well-known philosopher in the Western Canon for 1,500 since the Ancient Greeks such as Aristotle and Plato in 300 B.C.

In his book the Summa Theologica, He wrote what have become known as the Quinque Viae or the Five Ways which are logical proofs or apologetics for the existence of God. The very first is the Argument of the Unmoved Mover which is Aristotle’s exact argument (found here) with the addition of a logical step that was implied by Aristotle. Also using the vocabulary of “change”, Aquinas explicitly acknowledges the issue of the infinite regression:  if as our experience tells us, change is always caused by some prior change, then the question can always be asked “what caused that change?”  He, as many but not all, people do, considered the infinite regression to be a logical fallacy and simply asserted that it was obvious that there could not be an infinite regression and asserted that all Jews, Muslims, and Christians understand that the very first mover is understood to be God.