Anselm defines God as “that which nothing greater can be conceived”. This is his basic definition of God for the sake of his Ontological Argument. It’s interesting that he would use this definition as it seems to go against the medieval mysticism of the incomprehensible nature of God. It appears that human reason is fully capable to understand what God is since he is “that which nothing greater can be conceived”. Dionysius writes about the darkness in the mystery of the incomprehensibility of God. Anselm seems to take a stance that we can understand the nature of God. The Ontological Argument will argue this definition of God which presupposes comprehension of God. The Argument’s premises and conclusion can be stated this way:
Premise 1: God is that “which nothing greater can be conceived”.
Premise 2: The fool must admit that “that which nothing greater can be conceived” is conceivable.
Premise 3: If “that which nothing greater can be conceived” is conceivable, then it must exist outside the mind to be truly “That which nothing greater can be conceived”.
Premise 4: “That which nothing greater can be conceived” is conceivable.
Premise 5: Therefore, “that which nothing greater can be conceived” exists outside the mind.
Premise 6: “That which nothing greater can be conceived” exists in reality.
Conclusion: Therefore, God exists.
Alvin Plantinga’s version:
Anselm’s ontological argument has been revised by Philosopher Alvin Plantinga. Instead of Anselm’s definition of God, Plantinga defines God as the greatest conceivable being or a maximally great being. It’s more helpful since being is implied instead of a thing. Being implies personhood, which deals with objections that may ask: “Why does “that which nothing greater can be conceived” be personal? Plantinga’s argument will deal more with modal logic, which deals with possible worlds semantics. This does not mean multiple worlds or a multiverse. Rather deals with possibility and necessity of things. Model logic deals with how the world could have been and not been. We are contingent beings and could have failed to exist. Unicorns could exist in some possible world, but not all possible worlds. This is important to understand before this argument is laid out. Here is the argument in its logical form:
Premise 1: It is possible that a maximally great being exists.
Premise 2: If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
Premise 3: If a maximally great being exists in some possible world, then it exists in every possible world.
Premise 4: If a maximally great being exists in every possible world, then it exists in the actual world.
Premise 5: If a maximally great being exists in the actual world, then a maximally great being exists.
Conclusion: Therefore, a maximally great being exists.
This argument states that if it is even possible for a maximal great being to exist, then this being actually exists. For this argument to follow, a maximally great being must have possibility of existence, so the world could have been this way. However, to be maximally great, this being would have to exist in every possible world. This is true because this maximal great being could only be maximally great if this being exists in every possible world. This argument basically argues that to be maximally great, necessity must be part of this being’s nature.
The principle of sufficient reason can be applied to this argument to help strengthen it. This principle states, that everything has an explanation for its existence, whether in the necessity of its own nature or something external. A maximally great being would not be contingent, but rather have the property of necessity. Necessity would imply that things with necessity have to exist in all possible worlds. Such as the laws of logic and truth itself. A maximally great being would have this in order to be maximally great. If there is a world in which this being could not exist, then it would not be maximally great. For this argument to be unsound, the objector would have to show that a maximally great being cannot exist in any possible world. To do this, they would have to show a logical contradiction in the idea of a maximally great being. Of course, the fool(non-believer) will have other objections.
Dealing with Objections:
Anselm did not receive as many criticisms in his day as Plantinga receives to this day. One of the main objections to Anselm’s version was the assertion that it’s possible to think of “that which nothing greater can be conceived” to not exist. Anselm simply replies that if this is the case, then it would not be “that which nothing greater can be conceived”. This can seem a bit circular since there might be a world in which the greatest thing conceived only exists in the mind. This is why Plantiga’s argument is better worded and employs model logic. A maximally great being would have to exist in every possible world to be maximally great.
Some objectors to Plantinga’s argument give an argument from analogy. Couldn’t there be a maximally great pizza? The answer is no because what would pertain to this pizza? Taste is subjective, so there’s no real way to get a true standard by which you could determine for a pizza to be maximally great. Plus, pizza can be eaten and not exist in a possible world. This of course is just exercising the thoughts that come from this silly objection. Another objection is the mere assertion that there is a world in which a maximally great being doesn’t exist. This of course is never demonstrated and is a mere assertion. As asserted before, to show this argument to be unsound, the objector would have to show a logical contradiction in the definition of a maximally great being.
A final, common objection to this argument is an epistemological one. Scientism is used to argue that science is the only real way to truth, so arguments from logic need empirical data to back up the premises. It can be simply asked, has scientism demonstrated scientifically why it should be accepted as the best epistemological methodology? The answer will be no, so the objection does not follow at this point.
For God to be “that which nothing greater can be conceived” he must be a maximally great being that exists in every possible world. Anselm was onto this and so is Plantinga with his argument. Anselm would say that to understand this being, we must first believe in order to understand. I would argue that since we do understand that God is a maximally great being, we should believe in order to understand him. The Ontological argument is one of many arguments in the cumulative case to show why we should have faith in God in order to understand him.
Anselm's Major Works: https://www.amazon.com/dp/B006L2XMBK/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1
Ontological Arguments Book: https://www.amazon.com/Ontological-Arguments-Classic-Philosophical-ebook/dp/B07GNJLV18/ref=sr_1_1?crid=13JV17YF6T1SJ&keywords=ontological+argument&qid=1555186229&s=digital-text&sprefix=Ontological+%2Cdigital-text%2C136&sr=1-1