1. Something undeniably exists: I cannot deny my own existence.
2. My existence is either impossible, possible (contingent), or necessary.
3. Since my existence is contingent, I must be currently caused to exist by another.
4. There cannot be an infinite regress of current causes of existence.
5. Hence, there must be an uncaused first Cause of the present existence of all contingent beings.
6. This uncaused first Cause must be necessary, infinite, eternal, simple, immutable, and one.
The thomistic cosmological argument avoids the Leibnizian error of attempting to ground God’s existence in rational necessity. Instead, the starting point for the thomistic argument is an undeniable existential truth: I exist. My existence is undeniable for the simple reason that I have to exist in order to deny my existence. Therefore, it is an incontrovertible fact of reality that something exists. It may be logically possible that nothing exists, but it is actually undeniable that something does indeed exist. Thus, rather than arguing for the existence of God in the real of pure reason, the thomistic cosmological argument is existential, grounded in real, undeniable existence.
My existence is either impossible, possible, or necessary. Since my existence, while logically deniable, is actually undeniable, then my existence is not impossible. Therefore, my existence is either possible (contingent) or necessary. A contingent being is one that can not exist and a necessary being is one that can not not exist. My existence is not impossible, for I undeniably exist. But neither is it necessary, for my non-existence is at least possible, though not actual. And it is a fact that I came to be; I have not always existed. It is clear, then, that I am not a necessary being for (1) my non-existence is possible and (2) I came to be. Therefore, my existence is possible, or contingent.
The principle of causality says that “every effect has a cause,” or “every limited being is caused to exist by another,” or “nonbeing cannot cause being.” David Hume wondered whether we could actually discern exact causes. Much of what we attribute to causality, said Hume, really amounts to a post hoc fallacy: after this, therefore because of this. But even this greatest of skeptics flatly denied the absurdity that things can arise without a cause. While Hume is correct that we can often wrongly attribute a certain effect to a certain cause, the fact that there are effects must mean that there are causes. And if something undeniably exists, and that something cannot account for its own existence as in the case of a contingent being, then that something is an effect that was caused.
A contingent being, as a limited effect, requires a cause for its coming into existence as well as a cause for its continued existence. Only a necessary being requires no cause for its existence. By definition, a necessary being is a being that cannot not exist. If a necessary being exists, therefore, it must be uncaused, infinite, and eternal. A necessary Being must be uncaused, for if a necessary being were caused, then its existence would be contingent upon the cause. Likewise, a necessary Being must be infinite, for all finite beings need a cause of their existence. And finally, a necessary Being must be eternal, for a being that cannot not exist, if it exists, cannot have come into existence at some time. On the other hand, a contingent beingcan not exist, and requires a cause for its existence. A contingent being is one whose essence and existence are distinct. Its existence is not explained by virtue of its essence. Therefore, it requires a cause for its existence. Furthermore, not only does a contingent being require a cause for its coming into existence, but also for its continued existence. Only a necessary Being requires no cause for its continued existence. So for a contingent being to require no cause for its continued existence, it would have to become a necessary Being. But a contingent being cannot become a necessary Being since by definition a necessary being is not a being that can become anything; it just is. Neither can a contingent being cause itself; self-causality is a contradiction. I cannot cause my own existence for I would have to exist prior to my existence, which is impossible. Therefore, because I am a contingent being, my coming-to-be as well as my current existence is caused by another.
Something undeniable exists, and that something is a contingent being which must be caused to exist by another. But the being which is the cause of my existence is either an impossible, possible, or necessary being. Obviously, if a being caused my existence, it had to exist in order to be a cause, and therefore it cannot be an impossible being. The only remaining options are that the being which is the cause of my existence is either a possible (contingent) or necessary being. If the being which is the cause of my existence is a necessary being, then the we have found the necessary being. If the being which is the cause of my existence is contingent as I am contingent, however, then it too would require a cause for its existence. But that series cannot be infinite. In “looking backward,” the causal series must end somewhere or it could never have begun. In other words, if there were an infinite regress of causes, then there was never a first cause. And if there was never a first cause, then the causal series could never have begun.
One formidable objection to this link in the argument came from Immanuel Kant. Kant denied the impossibility of the infinite regress based upon the “antinomies of reason.” An antinomy of reason refers to a transcendent Idea in which both the thesis and its antithesis (contradictories) can both be proven true. Such antinomies, says Kant, follow from the failure to distinguish the appearance of the sensible world (phenomena) from things-in-themselves (noumena), resulting in self-contradictory concepts. For example, the propositions “a square circle is round” and “a square circle is not round” are false because they are both founded upon the self-contradictory notion of a square circle. Now, objects in time and space (in the cosmological argument here defended, that would be the “I” whose existence is undeniable) refer to things in appearance, and to give them a self-subsisting existence apart from appearance is to say that experience exists apart or before experience, an obvious contradiction. Likewise, it is impossible to declare the world finite or infinite because these transcend experience; they are mere Ideas. Quite contradictorily, the magnitude of the world of sense would have to exist apart from sense. Thus, metaphysical inquiries are fruitless because they attempt to know the unknowable. That is, metaphysics seeks to know the thing-in-itself when in reality all that can be known is the world of appearances. Instead, Kant concluded that the necessary Being hypothesis merely provided a necessary rational unity to the human mind but was impotent to explain actual existence.
Kant’s antinomies were the direct result of his epistemology which bifurcated reality into the “thing-as-it appears-to-me” and the “thing-in-itself.” This bifurcation resulted from Kant’s synthesis of rationalism and empiricism, a synthesis which concluded that the categories of the mind imposed the form on the stuff of the world, thus making it knowable. While this was a brilliant synthesis of hundreds of years of epistemological wrangling, its end result was that we do not know reality until after it is formed by the mind. Thus, we cannot know the “thing-in-itself.”
Kant’s epistemology, however, is agnostic and, ultimately, self-defeating. Agnosticism says in effect, “I know that I cannot know.” Kant claimed to know that there was a “thing-in-itself” but claimed that we could not know anything about it. But you cannot know that something exists without also knowing something about that thing, however incomplete that knowledge may be. Pure “that-ness” cannot be known. Thus, the entire foundation upon which the antinomies of reason were based is faulty and Kant’s objection against the impossibility of an infinite regress fails. The mind does not supply the idea of a necessary being merely to provide rational unity, but finds the actual undeniable existence of contingent beings unintelligible apart from the existence of a non-contingent being. Therefore, the original argument is valid: there cannot be an infinite regress of current causes of existence. The only thing that can explain the current existence of a contingent being is the existence of a being which stands “outside” the causal series and is ultimately responsible for the causal series in the first place.
Some limited, changing, contingent being undeniably exists. The present existence of every contingent being is caused to exist by another. There cannot be an infinite regress of causes, which means that the causal series must have had a beginning. But if it had a beginning, then there must exist a Being which is not caused, but in fact is the cause of all other existence. Another way to state the argument is as such: Something now exists, therefore something has always existed. If something now exists, which is undeniably the case, then there could never have been a “time” when nothing existed. For if there was ever a “time” when nothing existed, then nothing would still exist, for something cannot come from nothing. But there is undeniably something, therefore there has always been something. But if there has always been something, then there must be a Being which exists without being caused to exist. That Being is the uncaused first Cause of the cosmological argument.
The cosmological argument does not merely tell us that God exists without telling us something about God. To do so would be to fall back into the Kantian error of claiming to know pure that-ness. But the knowledge of God which is derived from the cosmological argument is dependent upon two critical principles: analogy and the “via-negativa.” First, all talk about God must be either univocal, equivocal, or analogical. In other words, when we describe God, either (1) there is a one-to-one relationship between our words and God (univocity), or (2) the exact opposite, that God is wholly other than our descriptions of him (equivocity), or (3) something in between the two (analogy). Univocal language is impossible because God is infinite and God-talk is not. Equivocal language, on the other hand, leaves us in complete agnosticism about God. Therefore, if our God-talk is neither univocal nor equivocal, then it must be analogical. If it is not entirely the same nor entirely different, the only other option is that it is similar. What we say about God has an analogical relation to His being.
| method | explanation | result |
| Univocal | one-to-one relation | impossible due to the infinitude of God and the finitude of our language |
| Equivocal | God is “wholly other” | agnosticism |
| Analogy | God is similar to our descriptions of him | the only legitimate way to talk about God |
Second, since a necessary Being cannot create another necessary Being, 1 all the effects caused by God must be contingent beings composed of both actuality and potentiality. 2 Thus, God as Pure Act is similar to His effects in their actuality but dissimilar in their potentiality. This dissimilarity is known as the “via negativa,” or way of negation, and all adequate God-talk is dependent upon it. Anything predicated of God must be predicated in accordance with his Being. Since God is infinite, all predications made of Him must be removed of all limitations to correctly apply to Him.
There are several truths about God yielded by the cosmological argument. To name just a few, the cosmological argument demonstrates that God must be (1) necessary, (2) infinite, (3) eternal, (4) simple, (5) immutable, and (6) one.
(1) God must be a necessary Being. This is apparent from the fact that if God were not a necessary Being, then he would be a contingent being. But if God was contingent, then he too would require a cause. And if God required a cause, then the cause is greater than him by virtue of its pre-existence and ability to bring God into existence. God, however, is by definition the greatest of all possible beings, so it is absurd to posit a being greater than him. Further, if God required a cause, would his cause also require a cause? If yes, then that series must either end at a first cause, or spiral into an infinite regress. If no, then God’s “cause” would be the first Cause. But the first Cause is exactly what the cosmological argument seeks to discover. In the end, it must be concluded that (a) an infinite regress of causes is impossible and (b) therefore, a first Cause must exist. And by definition, a first Cause must be uncaused (self-causality, as mentioned above, is a contradiction – even for God), and an uncaused Being is a being that cannot not exist, i.e., a necessary Being. Thus, God is a necessary Being.
(2) The cosmological argument yields the truth that God is infinite. If God were not infinite, i.e., if He was finite, then he would by definition need a cause, for every limited being needs a cause. John Stuart Mill believed in a finite God. But if God was finite, then He would need a cause for His existence just like any other contingent being. This is also where Bertrand Russell erred. He misinterpreted the principle of causality to mean that every thing needs a cause. And if every thing needs a cause, then God too needs a cause. But the principle of causality does not teach that everything needs a cause but that every limited thing or everything that comes to be needs a cause. Therefore, on the basis of a correct understanding of the principle of causality, if God is the uncaused first Cause, then by definition he must be infinite. For if he were finite, he too would need a cause for his existence. The first Cause is the unlimited limiter of all finite beings.
(3) God is eternal. If something now exists, then something has always existed. As a necessary Being, God cannot not be. That means that he has always existed. Unlike temporal beings, he has no befores or afters. Very simply, He is. The God who is the pure Act of the cosmological argument is one with the I AM who revealed Himself to Moses (Ex. 3:14).
(4) God is a simple Being. He is not composed of parts. In contrast, the beings of our existence, as evidenced by the fact that they all undergo change, are composed of act and potency. A being that is composed of act and potency is a limited being, 3 and a limited being requires a cause for its existence. If God was composed, He would need a composer and would not then be the first Cause. But since God is the first Cause, and since the first Cause is uncaused, it must be uncomposed, pure Act. And uncomposed being is a simple Being. Thus God is simple. A contingent being is one in whom essence and existence are distinct. In God, as a simple Being, essence and existence are one.
(5) God is immutable. To change is to become other than what one was. But change requires composition of being, for in change part of a being remains the same and part of it changes. Because God is pure Act, and is not composed of act and potency, He has no potency for change. Therefore, it is impossible for God to change.
(6) God is one. Since God is without limit, there cannot be more than one God. There cannot be two infinites. For there to be two or more Gods, one would have to lack some characteristic found in the other; otherwise there would be no way to differentiate them. But if one of the “Gods” lacked any characteristic of existence, then it would not be an unlimited being, and thus not God. Therefore, there can only be one unlimited, infinite, immutable, pure Act of Being. There can be just one uncaused first Cause.
One final point should be noted. The cosmological argument here espoused is not simply arguing that there was a first Cause that began the whole series of causes but is not known to now exist. On the contrary, this “vertical” argument, by beginning with the current existence of a contingent being demonstrates that not only is a first Cause necessary to begin the series, but is necessary to explain the current existence of contingent beings. Recall from point three that “once a contingent being, always a contingent being.” A contingent being is always contingent on another being for its existence. Therefore, since a contingent being currently exists, and an infinite regress of causes is impossible, a necessary Being must currently exist to explain that current contingent existence. Since the argument began with the undeniable truth that there currently exists a contingent being, then it demonstrably follows that a necessary Being likewise currently exists. Furthermore, since by definition a necessary Being cannot not exist, then if it can be demonstrated that the existence of such a Being is required to explain contingent existent, then that demonstration is sufficient to show that the necessary Being must continue to exist, for such a Being cannot not be.
FOOTNOTES
1:A necessary Being by definition is a being that cannot not exist. Therefore, it is impossible for a necessary Being to be created (come-to-be), even by another necessary Being.
2:There are only three possibilities for being: pure potency, pure actuality, or an act/potency composition. Pure potency, by definition, cannot exist. It has no actuality. Moreover, pure act cannot create another pure act, for to be created is to be limited, or finite. And pure act is devoid of all finitude. Therefore, any being created by God must be an act/potency composition.
3:This is by definition. Potency limits act. Therefore, any being that is composed of act and potency has its act limited by its potency. A limited act is a finite being.