Let us briefly go over some of the cosmological arguments.
Lucilius Balbus, the Stoic character in Cicero’s De Natura Deorum, presents an allegorical argument: "If you see a spacious and beautiful house, you could not be induced to believe, even though you could not see its master, that it was built by mice and weasels."
The house to which he refers is the observed cosmos with the stars and planets seemingly moving in an unending order. Later Isaac Newton would hold a similar view, comparing the cosmos to the mechanism of a pocket watch. It is 'so obvious,' continues Balbus, "and so manifest as that there must exist some power possessing transcendent intelligence by whom these things are ruled."
Inference is not proof. Such expressions assume certain things about the Universe, among them being that we live in a determinist universe. Cosmological arguments follow such a view by attempting to trace a series of causes and their effects back to an originating source. We come then to Aquinas' so-called Five Ways of proving the existence of his god.
First, things move and thus Aquinas posed that there must be some first mover, or primus mobile. This was an argument drawn from Plato. Plato’s primus mobile is the World Soul, herself born from the First God who was himself a manifestation of the One. One counter-argument to Aquinas is that he took matters only so far, never arriving at an ultimate source as did the Platonists, and that he confused all deities into his one deity.
Second, Aquinas posed the idea of a first cause, again drawing from Classical philosophers. A first cause, even if granted, would not in itself prove the existence of an omnipotent, omniscient, and compassionate being, call her god or whatever. A first cause would equate with Plato’s demiurge, the seminal seed held in the womb of the World Soul, who is the Second God, the Logos that brought order to the material World, but was not a creator as posed by Gnostic or later forms of Christianity.
Aquinas' third proof is that things that exist are only born from things that existed prior, and thus there must have been a necessary being, one having its own necessary existence in itself and not born from another. Otherwise there is an infinite series of things, all first originating out of nothing or else, since nothing comes from nothing, there must not be anything in existence now, either of which proposition is absurd. Basically Aquinas’ third proof is just a restatement of his second. He begins with the observation nihil ex nihilo creatio but then turns around to contradict himself by saying that something does exist that was not created from another, and that this god created all else ex nihilo creatio, otherwise, if she created everything from herself Aquinas would have entered into a form of pantheism, which he has been accused of doing. His first three arguments suffer from the same misconception. If it is a determinist world, one of cause and effect, how can you then claim the existence of something that wasn't caused, or not created by something else, or moving but unmoved by another? It poses something beyond the universe, or other than the universe, when the claim is that there is only the universe. It is no wonder that people get so befuddled over trying to understand christian rationalizations. Better to start at the beginning, with the ancient philosophers, before christians tried bending this to their own preconceived notions.
Aquinas' fourth proof runs along the same line as did Anselmo’s, only Aquinas tried to avoid the idea that existence was itself a quality explained by gradations toward perfection. He poses that all things are relative to one another and that there must therefore be something that is truest, best, noblest, most beautiful, "and something which is uttermost being." But then what is "uttermost being" here if it is not posed as a quality in the same way that Anselmo did? He then goes by convention, saying simply that this assumed being of every perfection, "this we call God." There is no reason to assume, as Christians do, that a single deity would possess every perfection. Minerva, Juno, and Venus are each most beautiful, yet in each Their own way. And there are other qualities of course, which Christians decline to associate with their god, forming the dichotomy between an ultimate good god and an ultimate evil god. In Platonism the One is also the Good, being the source of all that is beneficial, wise, and good. From the Good all things manifest downward so that there are gradations of things further away from the Good, but nothing is so distant as to be absent of the Good or to be an absolute evil. With the Neoplatonist Proclus of Late Antiquity there are the seven Henads, deities in their own right, derived from the One that is. In the Elements of Theology (used by Aquinas) these are described in propositions 152 – 158 as generating, demiurgic, life-giving, protecting, purifying, perfecting, and elevating. Each of these divine henads in turn manifest in other Gods. Thus the life-giving henad manifests as Apollo, Helios, Ceres, Juno, Mana Gerneta, and Rhea-Cybele, while the protecting henad manifests as Uranus, Saturnus, Jupiter, Mars, Quirinus, and Cereus. The henads may be the result of a first cause, not a primus mobile however as they contributed to forming the World Soul. The point here is that an argument of gradations does not necessarily lead back to a single source, nor does such an argument support Aquinas' first three arguments. If anything, the ancient used such arguments to describe the existence of multiple deities.
With his fifth proof Aquinas brings us back to the cosmos as purposely designed by a transcendent intelligence. This is a sustaining god, a directing god. There is really no reason to assume that there is only one sustaining god rather than a collection of gods as Seneca held in his Providentia Deorum, or as the Book of Psalms from Judaism has a Council of Gods. It is only a certain prejudice towards monotheism that identifies a primus mobile, a first cause, a necessary being, and the source(s) of all that is good and beneficial together with this demiurgic designer of the universe. A particular weakness, I think, of Aquinas' arguments is with his assumption that there can be only one God. The Five Ways are otherwise disconnected unless you accept his assumption. However it does not really make a difference whether you believe in one God or a multitude of Gods and Goddesses, this form of proof by design is flawed. Our understanding of Nature today is far closer to Epicurean views than to Plato’s or Aristotle’s. The universe is more of a balance between chaos and order. Atoms come together to form bodies, and then dissolve, not by any design or through the will of some overseeing deity. Celestial bodies tend to crash into one another. Whole species become extinct. Change, transformation, evolution are the true order of Nature. It is a very disorderly house that mice and men find themselves in. And there are Gods dwelling in it as well. Just not the kind of Gods rationalized, invented, imagined by Aquinas.
Now then, if there were a first cause, there is nothing to indicate that what followed was by design. If there is a first mover, there is nothing that shows what he began was designed to lead to what exists today. If there is truly only one thing with necessary being, and all other things draw their being from it, does that show in any way that the Universe is one by design? Likewise, how can gradation from an ultimate Good show design in the Universe? Then, too, if the Universe is designed in some fashion, there is nothing to show that the designer is the first cause, first mover, ultimate Good, or the necessary being assumed by Aquinas. Each of his arguments are assumed to stand on their own, and if any were disproved this would not necessarily mean that his basic assumption is incorrect. Also, when all five are disproved, it does not mean that no Gods exist. The counter arguments of atheists are just as flawed, first because they assume they need only refute the existence of the Judeo-Christian God, and by accepting that mistaken notion they also assume that by refuting one argument that they have disproved the existence of gods. They are flawed because they rely on human logic. Logic has its uses, but it is not the end-all in every matter. The real flaw with Aquinas and others like him is that they use human logic in an attempt to encompass the incomprehensible.
I suppose that there may be other arguments to pose as "logical" proofs, but in the end, susceptable to the counter arguments of logic, they would not amount to anything. Logic itself is a human invention. It has its value in trying to understand the universe, but it does have its limits. You cannot, as many have assumed, rely on logic to pose a proof with any degree of certainity. Logical proofs at best are only rationalizations of belief. The same is true in science, only in science there is a basic realization to the limits of human logic and that scientific paradigms can be changed as new evidence is collected and "rationalized" once more into a scientific theory. The same cannot be done by those religions that rely unquestioningly on the authority of a book. But not all religions do so, and there are other religious authorities with which to consult than some book. Living religions evolve over time just as any other organism, and some of these rely on a different sort of tradition where evolution of the tradition is incorporated in the belief system. I don't know whether we can use the "proof" as you originally intended, but we can take a different approach on the question.
Vale et vade in pace Deorum
M Horatius Piscinus