It is probable that God exists

I will offer three arguments for the existence of God that stem from the Thomistic tradition. It is up to my opponent to refute these arguments and to advance his own arguments to show that God's existence is not probable. The Thomistic Cosmological Argument #1 (TCA1)1. Whatever is in motion is moved by another.2. There exist beings in motion. 3. There cannot be an infinite regression of moved beings.4. Therefore, there must be a first mover. The term “move” as used in the first premise is synonymous with change, which Aquinas understood to be the actualization of a potential. In order for something to change, it must be acted on by an entity external to itself. Something cannot actualize its own potential to exist, as this would require that it exist before it existed, which is self-contradictory. Only what is already actual can actualize a potential. To hold that potency can actualize itself is to say that something can come from nothing, which is absurd. The third premise refers to a causal series that is ordered hierarchically. A hierarchal causal series is one in which the instrumental causes are related to each other simultaneously or essentially. The TCA1 is perfectly compatible with there being an infinite regress of temporally ordered causes. This distinction is important to keep in mind. To attack the TCA as if it were another cosmological argument, like the KCA, is to attack a strawman. What does a hierarchally ordered causal series look like? Aquinas uses the example of a stick being moved by the hand. The stick’s motion depends essentially on the hand, such that if the hand were to stop, then the stick would stop as well. Another example would be a set of gears, which move insofar as there is a first gear in motion. Because they are ordered simultaneously, a hierarchal causal series cannot regress infinitely. Even granting that such a series has an infinite number of members, this is not sufficient to explain the presence of motion. To claim otherwise would be like saying that a broom can brush by itself as long as it has a very long handle. [1] Or magine you have an infinite number of boxcars in motion. No matter how many boxcars you have, you must have an engine to impart motion to them, otherwise the entire chain will be motionless. The important point to note, as in the above examples, is that contingent things are passive recipients of motion. That is, they do not have the ability by nature to impart motion -- they must be given it by an external being. Just as gears do not move by nature, so do we not exist by nature. We must be continually be caused to exist by a being who just is existence. This being is a first mover who explains why the whole series is in motion. Note that this argument automatically rules out the objection "Who moved the mover? " Since it is literally the first mover, it is impossible for it to be caused. The Thomistic Cosmological Argument #2 (TCA2)1. There exists contingent beings.2. A series of causally related contingent beings cannot be infinite3. A series of causally related contingent beings must be finite.4. Therefore, there must be a first cause of the series of contingent beings. [2]This argument, while similar to TCA1, is different. Whereas TCA1 is based on the existence of causality, TCA2 is based on the existence of contingent beings. That there exists contingent beings is evident enough. The universe and everything in it could have not existed. In Thomistic terms, essence is different from existence: existence isn't contained in the nature of the universe or anything in it. If that sounds abstract, think of it this way: Is the reason you exist because you are a human? Is it part of your nature to exist? Obviously not. Then it follows that your existence must be caused by something else. But what about that thing's existence? Does it exist by virtue of what it is? No. But then it has to be caused by something else. Now can this chain extend back infinitely? It doesn't seem like it. Even if the set of causes has an actually infinite amount of contingent members, this does not explain the entire contingency of the entire set. There must be a being who exists from the necessity of its own nature that explains why this set exists. Perhaps an example will help. Suppose I want to borrow a typewriter. I go to my neighbor and ask him "May I borrow a typewriter? " Unfortunately, he doesn't have one, so he goes to his neighbor and asks him for one. However, his neighbor doesn't have one either. Now if you keep doing this, nobody ends up with a typewriter because everyone is a borrowing lender who must first have a typewriter in order to give it. The same for existence. If contingent beings exists, there must be a necessary being who simply has existence. The Teleological Argument 1. Natural entities either tend toward ends or they do not.2. If natural entities tend toward ends, then they are best explained by a person.3. Natural entities tend toward ends.4. Therefore, natural entities are best explained by a person. Unlike traditional Paley-style teleological arguments which appeal to considerations surrounding complexity, this version of the TA is based on inherent goal-directedness, making it in all respects a true teleological argument in the Aristotelian tradition. To say that natural entities tend toward ends is to say that they behave with a goal, purpose, or function in mind. It is to say, for example, that the heart tends toward the purpose of pumping blood or that the eye has the function of seeing. That natural entities of all sorts behave in this way is undeniable. Indeed, it is presupposed by discipline of medicine, which seeks to restore bodily functions to the way they ought to be. It accounts for why certain effects are regularly brought about by their causes . A match tends to cause fire -- and not rainbows -- when lighted because that is its function. A plant matures according to its kind because that it is directed toward that sort of development. Teleology is also present in the inorganic realm, such as in the water and rock cycles. If causes weren't directed toward their effects, then there is no reason why causes can't literally produce any effect. Now to speak of causes as being directed toward certain purposes or functions is to admit to a type of intentionality. Intentionality is of course the mark of the mental, and there thus must be a mind who imparts teleology to the natural order. Just as how a match derives its function from the intentions of its creator, so do natural entities derive their characteristic behaviors from a grand creator. Similarly, to say that a heart ought to pump blood or that a human ought to think rationally is to admit to the existence of normativity, which also indicates the presence of an agent. Why God? This all being said, what reason is there to believe that this being is God? From the three arguments I have offered, we can deduce several characteristics of this being. The first two arguments show that it is eternal and uncaused. It also must be simple (per TCA1): having no parts and incapable of change. The third argument demonstrates that it must be a mind of tremendous intellect, implying that it is also personal. Finally, per TCA1/2, because its essence just is its existence, there can be only one of this being. It additionally must have all perfections by virtue of its being purely actual (Otherwise it would be a changing being, and thus contingent). This, as Aquinas put it, is a being of pure actuality which “everyone takes to be God. ” _______Sources1. Edward Feser, Aquinas: A Beginner's Guide (Oneworld: 2009) pg. 72.2. W. David Beck, "A Thomistic Cosmological Argument" in Francis J. Beckwith, William Lane Craig, and J. P. Moreland, To Everyone an Answer (IVP Academic: 2004) pgs. 95-107.