Aristotle’s “Unmoved Mover” and Those Who Are “Without Excuse”
In Paul’s discussion of the sins of the Gentiles, the apostle explained that those Gentiles who refused to acknowledge the existence of a higher power (one that is responsible for the origin of the natural order) had no excuse for their failure in this regard:
For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who suppress the truth in unrighteousness, because what may be known of God is manifest in them, for God has shown it to them. For since the creation of the world His invisible attributes are clearly seen, being understood by the things that are made, even His eternal power and Godhead, so that they are without excuse, because, although they knew God, they did not glorify Him as God, nor were thankful, but became futile in their thoughts, and their foolish hearts were darkened (Romans 1:18-21).
If it is the case that those who refuse to believe in God (despite evidence He has presented in the material world) are without excuse, then we would expect to learn of people who, while perhaps lacking special revelation from God, nonetheless applied their God-given rationality to develop belief in a being that is responsible for the physical world. We find just such an example in one of the most famous and important philosophers, Aristotle.
In Aristotle’s Physics, the philosopher addresses the question of motion. After a lengthy discussion on the nature of motion and the immediate causes for motion, Aristotle addresses the remote cause for motion:
If everything that is in motion is moved by something that is in motion, either this is an accidental attribute of the things (so that each of them moves something while being itself in motion, but not because it is itself in motion) or it belongs to them in their own right. If, then, it is an accidental attribute, it is not necessary that that which causes motion should be in motion; and if this is so it is clear that there may be a time when nothing that exists is in motion, since the accidental is not necessary but contingent.... But the non-existence of motion is an impossibility (1984, 1:428, parenthetical item in orig.).
Aristotle, exemplary in his philosophical quest at this juncture, simply asks himself why there is motion. His conclusion, after a lengthy discussion, is essentially this: Because it is undeniable that motion exists, then there must be a first cause for the motion—an unmoved mover, whose movement (or causing of movement) is not an accidental property of His, but rather a necessary component of His being. Whereas each item in the created order is in motion because it has been moved by a distinct mover, the unmoved mover must possess the quality of motion (or the causing of motion). Aristotle lived prior to the Christian age, and was not a Hebrew; yet in his quest to understand the natural order, he was not prejudiced against belief in the supernatural.
Thomas Aquinas would adapt Aristotle’s argument to formulate what we know as part of the cosmological argument for the existence of the God of the Bible (see Maurer, 2010; cf. Jeffcoat, n.d.):
Now whatever is in motion is put in motion by another.... For motion is nothing else than the reduction of something from potentiality to actuality.... It is therefore impossible that in the same respect and in the same way a thing should be both mover and moved, i.e., that it should move itself. If that by which it is put in motion be itself put in motion, then this also must needs be put in motion by another, and that by another again. But this cannot go on to infinity, because then there would be no first mover, and, consequently, no other mover.... Therefore it is necessary to admit a first efficient cause, to which everyone gives the name of God (1952, 19:12,13, emp. added).
Peter Kreeft summarizes Aquinas’ argument: “Since no thing (or series of things) can move (change) itself, there must be a first, Unmoved Mover, source of all motion” (1990, p. 63, parenthetical items in orig.).
The necessity of the unmoved Mover is obvious. Yet, Paul recognized that some had become so calloused by worldly concerns as to prejudice their hearts against the Creator. So, God “gave them over to a debased mind, to do those things which are not fitting; being filled with all unrighteousness, sexual immorality, wickedness, covetousness, maliciousness; full of envy, murder, strife, deceit, evil-mindedness” (Romans 1:28-30). Despite the forceful clarity with which God has revealed Himself to His creation, some will misuse their intellectual freedom and reject Him. May we, on the other hand, willingly receive a simple, yet critical, lesson from Aristotle and Aquinas concerning the necessary existence of our Creator.
Aquinas, Thomas (1952), Summa Theologica, trans. Fathers of the English Dominican Province (Chicago, IL: University of Chicago).
Aristotle (1984), Physics, trans. R.P. Hardie and R.K. Gaye, in The Complete Works of Aristotle, ed. Jonathan Barnes (Princeton, NJ: Princeton University Press).
Jeffcoat, W.D. (no date), “The Cosmological Argument for the Existence of God,” http://apologeticspress.org/rr/reprints/Cosmological-Argument-for-Exist.pdf.
Kreeft, Peter (1990), Summa of the Summa (San Francisco: Ignatius Press).
Maurer, Armand (2010), “Medieval Philosophy,” Encyclopaedia Brittanica, http://www.britannica.com/EBchecked/topic/1350843/Western-philosophy/8653/Thomas-Aquinas?anchor=ref365766.