The Ways of the Worldviews (Part 25): Thomas Aquinas’ “Five Proofs” for the Existence of God

I want to note that what much of what is contained in this post was covered in a few previous posts I wrote in my series about Richard Dawkins. Still, for what should be obvious reasons, I wanted to have this material at this point in this series as well. Enjoy.

Thomas Aquinas is most famous for his “five proofs” for the existence of God. Taking his cue from Aristotle, Aquinas looked at the reality of nature and existence and argued that it is entirely reasonable and logical to come to the conclusion that there is a God. We will now briefly touch upon these five proofs.

Proof from Motion
Contrary to what you might think, “motion” here does not mean literal moving from point A to B, like a car travelling from Chicago to New York. Rather, “motion” needs to be understood in terms of change. Hence, Aquinas argued that the very fact that things in the natural world undergo change points to the existence of God. As stated earlier, this has to do with the concepts of potentiality and actuality. Simply put, Aquinas argued that nothing can undergo change unless it is “put in motion” by another. For example, a car engine has the potential to run so that the car can leave Chicago and go to New York, but it can’t turn on itself. It’s potential must be “turned on” by someone or something else. This is true with everything: change doesn’t happen by itself; it must be initiated by something other than itself. Or as Aquinas said, “Whatever is in motion must be put in motion by another” (ST 1.2.3).

Yet if that is the case, how did change ever begin in the first place? Enter God. Aquinas argued, “…it is necessary to arrive at a first mover, put in motion by no other; and this everyone understands to be God” (ST 1.2.3). By arguing for a “first mover,” Aquinas was not talking in terms of the order of time, as if God, way back when, created the universe, wound it up like a clock, and then set it in motion with all the change inherent in nature. Aquinas was talking, not in terms of time, but in terms of being. God was not “first in time,” for God was, in fact, outside of time. Rather, God is first in terms of being and existence. He is “pure actuality,” without any potentiality, and is thus the basis for all existence and change in nature.

Please note, Aquinas is not claiming that God is the first cause of everything in some sort of space-time sense, for to claim that would be, in fact, reducing God to a mere something else in the universe. Aquinas is not even arguing for “how the universe began.” For Aquinas, even if the universe itself is eternal, the fact is that things within the universe cannot cause themselves or undergo change themselves. Therefore, whoever or whatever is initiating those “causes,” whoever or whatever is “causing” things to change must be what we call God. But to fully grasp this would mean to understand what Aquinas means by “actuality” and “potentiality.” Here’s that in a nutshell:

Everything in the universe is some combination of “actuality” (i.e. what we are) and “potentiality” (i.e. what we can become, change into). For example, back in 1981, 12 year old Joel Anderson was 12 year old Joel Anderson, but with the potential to eventually become 47 year old Joel Anderson. And lo and behold, here in 2016, due to time, societal and cultural factors, and basic growth and maturity—here I am, the 47 year old Joel Anderson! But then here’s the thing that will really bend your mind: both the 12 year old and the 47 year old is still the same Joel Anderson! And I’m not yet the 80 year old Joel Anderson that I have the potential to be, but given various factors, I will one day be that 80 year old Joel Anderson while still being the same Joel Anderson!

And so, everything in the universe undergoes change because everything in the universe is a combination of “actuality” and “potentiality”—that change, therefore, is the process in which we are becoming who we are. But since we cannot cause our own change, our becoming must be caused by someone or something else—but that someone or something else must be pure actuality, without any potentiality. That someone or something else is the “First Cause,” the Ultimate Reality, a being who is pure actuality, in whom no change can occur because He is already fully who He is. Biblically speaking, that “someone” is God—the Great I AM. All reality, and all potentiality within creation, is rooted in that Being, that First Cause, who brings everything into being.

Proof from Causality
The proof from causality will sound very similar to the proof from motion. In many ways, they actually overlap. Yet whereas the proof from motion addressed the question as to why things change, the proof from causality addressed the question as to why things exist at all. The philosophical term Aquinas used was “cause,” and he distinguished between ultimate causes, intermediate causes, and first causes. He argued that without a first cause, there would not be an intermediate cause, and there would not be an ultimate cause. But we need an example to flesh this out. Let’s say Bob and Betty get married and have a son, Bill—that will be considered the “first cause” that produced Bill. Bill then grows up and goes to college and gets a degree—this will be considered the “intermediate cause” that gave Bill the knowledge to launch a career.

Eventually, Bill, being the genius that he is, creates a new supercomputer that puts all other computers to shame—this is the “ultimate cause.” Aquinas would say that Bill’s supercomputer would have never come into existence in the first place if he had not gone to college, and he would have never gone to college if it had not ultimately been for his parents who got frisky one night and conceived Bill. Hence, everything and everyone gets its existence from another. Just like there is always a cause that invokes change in something that exists, there is also always a cause that invokes existence in the first place. Without a first cause, there wouldn’t be any intermediate or ultimate causes. And so, since such a thing could not regress to infinity, “…it is necessary to admit a first efficient cause, to which every give the name of God” (ST 1.2.3).

Again, as with the proof from motion, Aquinas is not talking about a first cause in terms of time. He was no deist who viewed God as a cosmic watchmaker who caused existence, wound it up with natural laws, and then left it to its own devices. Simply put, existence is not a one-time thing; existence is a continuous reality. Therefore, Aquinas’ argument for God here is that just as God is the basis for all change, He is also the basis for all existence—here and now, on a continual basis, not back then and there. Aquinas’ argument basically is that God is the sustainer of all existence throughout time. Edward Fesser provides a good illustration on this point: “…for Aquinas, the claim that God made the world ‘is more like the minstrel made music than the blacksmith made a shoe;’ that is to say, creation is an ongoing activity rather than a once-and-for-all event” (88).

Proof from the Contingency of the World
This proof holds that “…the world of contingent things could not exist at all unless there were a necessary being.” But I’ll be quite honest, I couldn’t find much to say for this one. I hope the other four proofs are enough!

Proof from the Grades of Perfection
Aquinas’ fourth proof involves what he calls “grades of perfection,” particularly in terms of transcendental values such as goodness, and justice. This argument is actually very similar to the argument regarding the moral law C.S. Lewis puts forth in Mere Christianity. Simply put, this argument starts with the acknowledgment that we are constantly evaluating people and events on a moral scale. For example, for all the immoral behavior in America today, America is still most certainly more moral than the Nazis. Compare me to Saint Francis of Assisi, I’m pretty sure I’ll come out looking pretty bad; compare me to a Charlie Sheen, I come out smelling like roses. And so, whenever we compare moralities along these lines, what we are actually doing is comparing them to some accept standard of perfection. Therefore, Aquinas argues that “there is something which is truest, something best, something noblest, and, consequently, something which is uttermost being; for those things that are greatest in truth are greatest in being” (ST 1.2.3).

And yet, we would be mistaken if we assumed that Aquinas envisioned God as some sort of Platonic Form. After all, Plato’s forms were pure unchanging abstractions that were completely distinct from the particulars of the created order. If one thing is certain when one reads the Bible, it is this: God is involved with His creation. So, rather than viewing God as some abstract standard, Aquinas proposes that we view his proof in light of God’s participation in the natural order. Perhaps an illustration from the natural world will help. Think about how the basic elements of life like water and sunlight are “taken in” by plants to aid them in the higher form of plant life. And then think how plants are often eaten and “taken in” by animals to aid them in the higher form of animal life. And then think about how various animals are often eaten and “taken in” (along with various fruits, grains, and vegetables) by human beings to aid them in the higher form of human life. At each step of the way, the lower form of biological life participates in the development and maintenance of the higher form of life. Or to put it another way, the higher form of life incorporates the lower form of life into its own, and thus further perfects it.

Aquinas thus argues that, just as this is true on the biological level, it is also true when it comes to transcendent values. Every time someone participates in a good, truthful, or noble act—no matter how great or small—that person is, in fact, pointing beyond his own particular good, truthful, or noble act to some higher form/degree of goodness, truthfulness or nobility. Therefore, any value within human morality, by virtue of its being inherently relational and participatory (i.e. “justice” only can be achieved when there is a relationship between two or more people), inevitably points toward and participates in a higher degree of virtue, of participatory moral perfection. This, therefore, points to the existence of God.

Proof from Finality
Perhaps Aquinas’ most important argument for the existence of God is his teleological argument. (It should be noted that ever since the so-called Enlightenment, modern philosophers, to the detriment of our modern world, have largely ignored this argument). In its most simplest terms, Aquinas’ teleological argument is that all things in the natural world are goal-directed and thus have a purpose. Just as an archer shoots an arrow at a target, all things in natural are directed toward a final end, namely God. Or as Aquinas himself says, “Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God” (ST 1.2.3). Simply put, everything done has an effect and purpose. The very concept of “purpose,” though, denotes some sort of intelligence, for it seeks to understand why something happened. Why did Oswald kill Kennedy? Why did Al-Qaeda fly planes into the twin towers? Why? That is a question intelligent beings ask, because “purpose” is something intelligent beings know exist.

Indeed, nothing in the universe at all can be explained or truly understood without this concept of purpose. Indeed, as Fesser has stated, “…it is impossible for anything to be directed towards an end unless that end exists in an intellect which directs the thing in question towards it. It follows that the system of ends or final causes that make up the physical universe can only exist at all if there is a Supreme Intelligence or intellect outside the universe which directs things towards their ends” (117).

The reason why Aquinas’ teleological argument regarding final causes has been discarded by modern philosophers and many in the scientific world today is that it argues that meaning and purpose in the world point toward the reality and existence of God. Yet ever since the so-called Enlightenment, the Christian worldview that was responsible for the resurrection of Europe and the explosion of arts, literature, architecture and scientific inquiry, has faced a violent assault by the worldview of philosophical naturalism, that starts with the presupposition that there is no God and that the natural world comprises the entirety of reality. Simply put, philosophical naturalism states, “If it cannot be scientifically tested and analyzed, then it cannot exist.”

Therefore, when it comes to explaining creation of the natural world, those who hold to philosophical naturalism (i.e. atheism) try to argue that the theory of evolution “proves” atheism. But then they go even further. Men like Sam Harris even go so far to argue that morality itself is simply the result of atheistic evolutionary forces. Or even more simply put: it was blind chance that brought about natural life, and it was blind chance that brought about morality. Evolution, they claim, explains both biological life and human morality. Of course, the problem with that explanation is that it is, after all, an explanation—and by virtue of being an explanation, it is attempting to prove something, give meaning to a phenomena…and that action is evidence of intelligence and purpose, the very thing that philosophical naturalism, by very definition, utterly rejects. Therefore to try to give a convincing argument that the universe is purposeless, meaningless, and the result of random, blind forces, is to do something that you are arguing doesn’t exist—namely give a purposeful, meaningful, intentional explanation for the way things are. The point is simple: nothing in the universe makes sense without the existence of final causes.