Of all the arguments for the existence of God, this argument is perhaps the most controversial and confusing, but when understood correctly, Alvin Plantinga’s ontological argument is perhaps one of the strongest arguments in academia for the existence of God. Because this argument is prone to misunderstanding, a fair amount of groundwork must be laid first. I would ask the reader to tread through this blog carefully in order to not misinterpret what this argument is saying.
First of all, how is God defined? God is traditionally defined by theists as a Maximally Great Being (MGB). If something else was greater than God that being would be God, but the question to ask is what makes a being maximally great? For a being to be maximally great, it would have to be all-powerful, all-knowing, and morally perfect in every possible world (which is another way of saying it would have to exist necessarily). In other words, it would have to possess properties know as “Greater Making Properties” and it would have to possess these properties to their fullest extent. It is hard to imagine intrinsic values which could cause a being to be greater than that which these attributes already ascribe. These values encompass the complete sum of greatness. These values includes love, knowledge, power, etc. If a being possesses these attributes to their fullest extent, it is maximally great.
A Maximally Great Being would not only need “Greater Making Properties,” but it must also exclude “Lesser Making Properties” or properties which make it less good for a being to have. Such lesser properties include cruelty, ignorance, and weakness. If a being possessed any of these attributes, it would not be maximally great.
Thus, this is how God is defined for the argument: He is a Maximally Great Being who possesses the total sum of “Greater Making Properties” to their fullest extent, and He does not possess any “Lesser Making Properties.” Therefore, He is all-powerful, all-knowing, and morally perfect in every possible world.
But, what is a possible world? In philosophy, to speak of a possible world is to speak of a hypothetical scenario in which if the world was a certain way, things would have been that way. For example, unicorns do not exist in the actual world, but it is easy to conceive of a possible world in which unicorns do exist. It is also easy to conceive of a possible world in which horses do not exist. They could exist in some possible world, but not others. They don’t have to exist, but they do. These things would be known as contingent, and they include plants, minerals, animals, and even humans. Contingent things only inhabit some possible worlds.
Are there things which could not exist in any possible world? Yes, and these things are known as impossible. These things would include logical incoherencies and self-contradictions. Examples include a married bachelor, a square-circle, the shape of the color purple, or the smell of a mathematical equation. These things are logically incoherent, so one cannot conceive of them existing in any possible world. Therefore, these things exist in no possible world.
Are there things which must exist in every possible world? Yes, these things are known as necessary. These are things which are eternal and changeless. Some mathematicians believe that numbers fall into this category. To them, numbers are not created entities, but rather 2 is the number 2 purely out of the necessity of its nature; necessary things cannot not exist.
Where does God (or a MGB) fit into these categories? It depends on whether or not He exists. Many philosophers agree that if God exists, He would have to be a necessarily existing thing. According to the ontological argument, if God does not exist, then there must be something incoherent or logically impossible about a MGB. Why could not a MGB be contingent? Because of the characteristics of said MGB. A MGB would have to be all-powerful, all-knowing, and morally perfect in every possible world. A MGB would not match the description of a contingent being, and if it did, it would not be maximally great therefore failing to meet its own attributes given to a MGB.
Now, we get to the argument. This argument is a deductive argument meaning that if the premises are true, then the conclusion is necessarily true. Here is the argument:
1) It is possible a Maximally Great Being (MGB) exists.
2) If it is possible a MGB exists, then it exists in some possible worlds.
3) If a MGB exists in possible worlds, then a MGB exists in every possible world.
4) If a MGB exists in every possible world, a MGB exists in the actual world.
5) If a MGB exists in the actual world, then a MGB exists.
The argument contends that if a MGB possibly exists, then by the way possible worlds are understood, a MGB must exist in some possible worlds. If it is possible, it inhabits a possible world.
But, a MGB is not just a being which inhabits some possible worlds; it is a being which is necessary, so it must inhabit every possible world.
But, if a MGB exists in every possible world (and since every possible world would include the actual world), it must exist in the actual world.
But, if a MGB exists in the actual world, a MGB exists.
Convinced yet? That’s fine, neither was I. What’s important to remember is that the point of the argument is not to be convincing; the point is to be logically valid and true. As I said before, this argument is a deductive argument meaning if the premises are true, then the conclusion must be true regardless of how convincing the argument overall may seem. The pertinent question is whether or not the premises are true.
Believe it or not, the only controversial premise is premise 1. Premises 2-5 are uncontroversial because if premise 1 is true, the rest of the premises follow from the first premise, but is the first premise substantiated?
Well, it certainly seems that way. After all, if there is nothing incoherent about a MGB (therefore making it impossible), that means it is possible a MGB exists, and the rest of the premises follow. The opponent of this argument must not only show that God does not exist. They must show it is impossible for God to exist. In other words, they must show there actually is something incoherent about a MGB.
Have any of these attempts been proven successful?
One of the most common attempts to prove omnipotence (or being all-powerful) logically incoherent has been the omnipotence paradox. It’s often purported as follows: can God create a stone so heavy that even He cannot lift it? If He cannot create the stone or lift said stone, He is not all-powerful. Therefore, omnipotence is an impossible trait. The problem with this argument is that it presents a logical impossibility as a defeater for omnipotence when logical impossibilities are not hindrances to omnipotence because logical impossibilities are meaningless statements. To ask God (an all-powerful being) to create a stone so heavy even He cannot lift it is like asking God to create a square-circle or a married bachelor. They are in essence incoherent and therefore meaningless statements, so they are not hindrances to God’s power. It is important to remember that omnipotence does not mean God can do anything. Such a view is not advocated in the Bible, and this view has serious logical problems facing it.
If God being unable to do or create logically impossible things bothers the reader (particularly the Christian reader), I would phrase my response this way: the Bible states God cannot lie (Hebrews 6:18). Why is that? Because God (as defined in the Bible and in this argument) is a morally perfect being. To lie is a moral imperfection. Therefore, God cannot lie for if He did so He would contradict Himself. In the same way, God cannot act upon logical impossibilities because these are incoherent and meaningless statements, and I would certainly say God cannot do anything meaningless.
Another attempt to discredit the argument is to substitute a unicorn, Thor, or any other obviously fictional or ridiculous entity in the place of a MGB in the argument. It is using a parody of the argument in order to render it false. The problem with a majority of these parodies is they try and equate a MGB (which would have to be necessary) with something which is contingent. The problem with arguing for a maximally great unicorn is that a unicorn is an entity which would be contingent and therefore not exist in every possible world. Further, for many of these parodies, the ridiculous entity they try to use does not have any maximal values or any clear intrinsic values. A classic example is the monk Gaunilo of Marmoutiers who responded to the original ontological argument postulated by Saint Anselm of Canterbury with what he called a “perfect island.” Substitute a perfect island (or an island greater than which no island could be conceived) for a MGB and one can see the argument does not work according to Gaunilo; however, the problem with this objection to the ontological argument is two-fold: 1) an island is a contingent being, not a necessary one (as a MGB would have to be), and 2) there are no obvious values which makes an island maximally great. It is relative to the person. What makes an island great for one person may not make the island great for another. Further, an island could never reach maximal greatness. There could always be one more palm tree.
In order to create a successful parody, the opponent of the argument must deposit a being which is 1) defined as necessary, and 2) able to reach maximal values (whatever those even are). These reasons are why every parody of the argument breaks down; once a person deposits a being that meets these two criteria, the being deposited starts to look a lot like the Maximally Great Being the opponent of the argument is trying to avoid in the first place.
Another common attempt to disqualify the argument is to say the argument begs the question. Philosophically, to beg the question is to assume the truth of the conclusion in a premise of the argument. In other words, you use the conclusion in a premise to argue the conclusion. Some contend that the ontological argument begs the question in the first premise where it states that it is possible that God exists. Objectors say this first premise is equivalent to the conclusion. Does this objection render the argument fallacious?
Not really. There exists a difference between statements being logical equivalent and being synonymous. The ontological argument sets up the first premise to be logically equivalent to the conclusion, and it relies upon the following premises to draw out the conclusion. This just makes it a valid deductive argument. In a deductive argument, the conclusion is usually hidden in the premises, and it requires additional premises to bring about the conclusion. No one reading the first premise, “It is possible a Maximally Great Being (MGB) exists,” would automatically assume this statement is synonymous with the statement, “A MGB exists.” The point of the argument is to bring the reader to the conclusion that if a person is committed to the possibility of God’s existence, it follows they must be committed to the belief in God or else hold logically contradictory views, and per the ontological argument, to postulate the possibility of the existence of God is to say God (or a Maximally Great Being) actually exists.
“For His invisible attributes, that is, His eternal power and divine nature, have been clearly seen since the creation of the world, being understood through what He has made” (Romans 1:20).