When children wake up on Christmas morning to filled stockings, they know there was someone that filled them. When we open the mailbox to find a letter, we know that there was both an originator of the letter as well as a person that brought it. In the same way, Thomas Aquinas reasoned in his Summa Theologica that the second way we can know of the existence of God is by the fact that everything which has been created has a cause.
Aquinas, and Aristotle before him, saw that everything in the world had a cause. Just as the child knows that someone placed presents in his Christmas stocking, Aquinas’s first premise is that everything has a cause and that there is an “order of efficient causes.” An efficient cause is one that causes something else to be. Aquinas reasoned that something could not cause itself. He would find David Hume’s argument that the universe could cause itself absurd, for as Aquinas states in his argument, something cannot cause itself because then it would be prior to itself. It cannot cause something if it does not yet exist.
An illustration of the principle of efficient cause can be found in the movie Gremlins, produced by Stephen Spielberg. In the movie, the main character, Billy, is given an odd and friendly creature called a Mogwai by his father. His father was warned when he bought the Mogwai to not let it get wet, feed it after midnight, or expose it to sunlight. Billy is delighted by his new pet which he names Gizmo. The chaos starts when Billy and his friend accidentally spill water on Gizmo and five more Mogwais pop out of his back. These are not friendly companions like Gizmo, and they begin wreaking havoc.
Gizmo was the efficient cause for the second generation of five Mogwais. They did not spontaneously generate on their own and did not cause themselves, or they would have existed prior to themselves. This is an example of premise one and two of Aquinas’s Second Way. The next premise is that in a series of efficient causes, it is not possible for them to go on infinitely;there must be that first cause. This starting point and a termination is shown in the regeneration of the Mogwais. Obviously, the first cause is Gizmo. An intermediate cause is shown when one of the second generation Mogwais, Stripe, who, after turning himself into a malevolent gremlin by eating after midnight, seeks to generate an army of gremlins by jumping into a swimming pool.
What follows both shows that even in a fictional account, there is an understanding that there cannot be an infinite loop of causes as well as the flaws in the logic of the film itself. While an army of gremlins are spawned, there is a point where the regeneration ends. Why is that? The movie gives no explanation. If the logic in the film were followed, there would be an infinite generation of gremlins as Stripe continued to spawn in the pool, each new gremlin would also continue to infinitely spawn new gremlins. However, even in science fiction there is an appeal to common sense, even if the writer does not give a coherent reason. We take our reasoning and understanding from our world and fill in the gaps where the logic of the fantasy breaks down. We know that the series of causes cannot continue to infinity, so we understand that the generation stopped, even though we are given no explanation. Aquinas’s third premise that a series of efficient causes cannot go on to infinity is intuitive to us.
Aquinas’s conclusion from these three premises is that there must be a first uncaused efficient cause, which is known as God. Gremlins does not give any sort of reason or explanation for the existence of its first cause, Gizmo. The reasoning was so unsatisfactory that fans had to create an entire cosmology around the movie that explained his existence and goodness when all of the rest of the spawned Mogwais were evil. These good Mogwais, which were spawned only once in thousands of regenerations, were called “Eternals.” It is natural to us that what is good should be eternal.
Believers are given a much better explanation of a first efficient cause than the nonexistent one given by Spielberg. The name God gives to Moses to identify himself to the Israelites in Exodus 3:14, “I AM who I AM” indicates this sense of an uncaused and uncreated being who brought all other things into existence. Genesis 1:1 states, “In the beginning, God created the heaven and the earth.” He was there before the beginning, an uncaused first efficient cause.
He is also the end cause. Aquinas gives a second reason for the impossibility of an infinite series of efficient causes in that as every cause works towards an effect; there must be an ultimate effect, a final result to be achieved. The final letter to believers before the Revelation of John ends with the words, “All glory to him who alone is God, our Savior through Jesus Christ our Lord. All glory, majesty, power, and authority are his before all time, and in the present, and beyond all time! Amen.” It is a reminder that no matter what happens, whatever God causes to be, he is already there and worked it according to his own good, and it was this that Jesus was referring to when he said, “It is finished.”
Carla Alvarez is a mother to three, owner of Legacy Marketing Services, and a graduate of HBU’s Masters in Apologetics program. Her philosophy in both business and apologetics is if what we think affects what we do, then the “how” is just as important as the “what.” As actions have a lasting impact, it is of utmost importance to develop right thoughts. She creates effective communications for clients at Legacy Marketing and writes about the Christian faith at RaisedtoWalk.org.
 Thomas Aquinas, Thomas Aquinas: Selected Writings, ed. Ralph McInerny, 3rd edition. (New York, NY: Penguin Classics, 1999) 4.
 David Hume, Dialogues Concerning Natural Religion (London: Hackett, 1980) 39.
 Chris Columbus: Gremlins. Directed by Joe Dante. Los Angeles. Warner Brothers. 1984.
 “Eternals,” Gremlins Wiki. accessed October 10, 2015. http://gremlins.wikia.com/wiki/Eternals.
 Jude 1:25, New Living Translation.
 John 19:30, Revelation 21:6