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What is the Ontological Proof God Exists?

Premise A: God has all perfection. 

Premise B: Existence is a perfection.

Conclusion: Therefore, God exists.

Ontology refers to the area of metaphysics that tries to answer the question of what exists. This kind of philosophical discipline relies largely on abstract reasoning to arrive at its conclusions—abstract reasoning meaning that if all you could do was think, how could you prove that something exists? The famous statement by the French philosopher and scientist, Rene Descartes (1596-1650), “I think, therefore I am,” is an example of ontological reasoning. Apologists have used ontological reasoning to prove the existence of God  

Anselm and the perfectness of God

Anselm (1033-1109), Archbishop of Canterbury, was the first to articulate the ontological proof for God’s existence in his work, Proslogion: Faith in Search of Understanding. The book contains a prayer in which Anselm asks God to reveal an argument for his existence that would be convincing to the atheistic “fool” of Psalm 14:1. That prayer is as follows:

And so, Lord, do you, who do give understanding to faith, give me, so far as you know it to be profitable, to understand that you are as we believe; and that you are that which we believe. And indeed, we believe that you are a being than which nothing greater can be conceived. Or is there no such nature, since the fool has said in his heart, there is no God? (Psalm 14:1). But, at any rate, this very fool, when he hears of this being of which I speak—a being than which nothing greater can be conceived—understands what he hears, and what he understands is in his understanding; although he does not understand it to exist.

For, it is one thing for an object to be in the understanding, and another to understand that the object exists. When a painter first conceives of what he will afterwards perform, he has it in his understanding, but be does not yet understand it to be, because he has not yet performed it. But after he has made the painting, he both has it in his understanding, and he understands that it exists, because he has made it.

Hence, even the fool is convinced that something exists in the understanding, at least, than which nothing greater can be conceived. For, when he hears of this, he understands it. And whatever is understood, exists in the understanding. And assuredly that, than which nothing greater can be conceived, cannot exist in the understanding alone. For, suppose it exists in the understanding alone: then it can be conceived to exist in reality; which is greater.

Therefore, if that, than which nothing greater can be conceived, exists in the understanding alone, the very being, than which nothing greater can be conceived, is one, than which a greater can be conceived. But obviously this is impossible. Hence, there is doubt that there exists a being, than which nothing greater can be conceived, and it exists both in the understanding and in reality.

The prayer proposes that God must exist because He is the greatest being that can be imagined, the being “which nothing greater can be conceived.” As Anselm unfolds the ontological argument for God’s existence in the chapters that follow the prayer, he proposes that if a being exists in the mind, but not in reality, then a greater being could be imagined who would exist in both the mind and in reality. But God, by definition, is infinitely great; no one can surpass his greatness. The Bible anticipates Anslem’s proof in Psalms 95:3, where it reads, “For the Lord is the great God, and the great King above all gods.” Psalms 145:3 again speaks about the greatness of God: “Great is the Lord, and greatly to be praised; and His greatness is unsearchable.” Since God is infinitely great, Anselm concludes, He is great in every conceivable way—including in the reality of His existence. 

Consider: As humans, we understand the concept of “good.” It is “good” for me to have a warm place to lay my head at night. It would be “bad” for me to be outside freezing in the cold. I can also imagine a “greater good” than having an indoor place to sleep. If I am sleeping on a floor, I can imagine the “greater good” of sleeping on a mattress. As I am sleeping in my house, I can imagine the “greater good” of sleeping in a beautiful palace. For each good that I can imagine, I can always imagine still greater and greater degrees of goodness—even if I have never experienced them. For instance, kindness is a form of goodness. If I am a “good” person, then I am kind to those around me. I have been kind on occasion, but I am not as kind as I could be. Nonetheless, I can imagine a being who is perfectly kind. If the concept of “good” is extended in all areas to its farthest possible extent, we come to the concept of “perfection.” Anselm argues that if there is a being who is perfect in all ways of being, that being must exist because one of the qualities of perfection is actual existence. This Being who is perfect in all ways of being, including of existence, is the One we call God. 

The Christian concept of God is one of a God who is “maximally great.” He is like a baseball player who bats 1.000 and always hits a homerun. He is like a bowler who bowls a perfect 300 on every game. He is like a contestant who could not lose on a game show. If He was on Jeopardy, He would answer every question exactly. If He was on Wheel of Fortune, He would know the exact weight to give the wheel so he could never lose money, and He would be able to solve all the puzzles without even asking for a letter. The God of the Bible is such a God. He is perfectly powerful (omnipotent), perfectly knowledgeable (omniscient), perfectly good (omni-benevolent), and perfectly present (omnipresent). He is a perfect being because He possesses to the maximum level all the qualities that are better to have than to not have. And God is maximally great in all areas without slipping over into logical fallacies. In the same way it is impossible for to have a “square circle” or a “married bachelor,” it is impossible for God to create a rock so big that he cannot move it. To speak of a perfect being, is to speak of God. As existence is a perfection of being, then God must exist. 

Does the perfect unicorn exist?

There are critics of the Ontological Proof. Gaunilo of Marmoutiers (eleventh century), one of Anselm’s contemporaries, made fun of his argument by proposing an “island that is greater than any other island that can be conceived.” Since such an island does not exist, he said that God’s existence couldn’t be proved by Anslem’s kind of reasoning. Similarly, the non-existence of unicorns could be seen to invalidate Anselm’s proof. My daughter is eight years old and, like many little girls, she loves unicorns. One day we talked about the perfect unicorn. According to her, the perfect unicorn is pink and has a purple mane and a sparkling white horn. This unicorn would also be magical and sentient. Of course, no matter how perfectly she imagines this perfect pet unicorn, my daughter knows the unicorn will never actually exist. Why can’t my daughter’s perfectly imagined unicorn or the perfect island of Gaunilo exist, but the perfect God of our thoughts be proven to exist by the very fact that he can be imagined? 

Anselm responded to his critics by replying that his proof only applied to concepts with necessary existence. Anselm meant that his argument only works for God’s existence because only God’s existence is necessary—certainly more necessary than the existence of a magical unicorn or a great island. A maximally great being grounds concepts like kindness and goodness that are part of perfection. A unicorn or island could not be the ground of perfection except by having all perfections. The perfect island, in order to be the perfect island doesn’t need all perfections, such as kindness or moral goodness for instance. If it had all perfections, it would no longer be an island, but something else (in fact, God). The ontological proof only works for God because there can only be one maximally great being or entity in existence. 

A modern defense of the Ontological Proof

Alvin Plantinga, an American philosopher, has offered a robust modern defense of the Ontological Proof. His argument is as follows:

Premise A: It is possible that a maximally great being exists. 

Premise B: If it is possible that a maximally great being exists, then a maximally great 

being exists in some possible world. 

Premise C: If a maximally great being exists in some possible world, then it exists in 

every possible world. 

Conclusion: If a maximally great being exists in every possible world, then it exists in the actual world.

In his discussion of the Ontological Argument, Plantinga brings in a hypothesis of modern physics that proposes the existence of multiple or parallel universes. He argues that the existence of God is not logically contradictory and is therefore possible. God being a logical possibility, it is possible that He exists in one of the possible universes proposed by multiple universe theory. Since it is possible for God to exist in one possible universe, then being maximally great, God must also exist in every universe—including ours. As a consolation to my daughter, Plantinga’s thinking makes it possible for my daughter’s unicorn to exist in some world that multiple universe theory makes possible. But since a unicorn is not a maximally great being, it does not exist in every possible world, and certainly does not exist in the one we can verify. 

When I think about God—in all the maximum perfection of his greatness and goodness—just the fact that I can think about Him in this way tells me that: God is THERE! 

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About the Author:  Dr. Daniel King is a missionary evangelist who has traveled to over seventy nations in his quest for souls. His goal is to lead 1,000,000 people to Jesus every year through massive Gospel Festivals, distribution of literature, and leadership training. Because of his experience and research on evangelism, he is widely regarded as one of the world’s leading experts in mass evangelism. As an evangelist, he has a deep interest in using apologetics to convince skeptics that God is real.

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