Evaluating the Ontological Argument




As we become convinced of any one particular view, our confirmation bias leads us to see all ‎arguments for our view writ large, and all arguments against it as easily swept under the rug. ‎However, a genuine pursuit of truth requires critical thinking about all arguments, including ‎arguments that are used for our own positions.‎

The Ontological Argument is an argument that has been, and still is, used as an argument ‎for God’s existence. But Christians are called to test everything, and hold on to what is good (1 ‎Thessalonians 5:21). And so if the Ontological Argument is tested and found wanting, then it ‎ought to be abandoned in our pursuit of truth and application of critical thinking.‎

In a nut shell, the Ontological Argument defines God as the greatest possible being, and then ‎argues that a being is greater if he/she/it exists rather than doesn’t exist, and so in order to be the ‎‎greatest possible being, God must therefore exist. Many are immediately suspicious of ‎this argument because it’s not based on points that can be either verified or falsified. If we ‎lived in a universe without God, then how could we disprove the Ontological Argument? If God ‎actually did exist, what could give weight to this argument that wouldn’t give weight to it if he ‎didn’t exist?‎

However, there’s a significantly greater problem with the Ontological Argument: it’s entirely ‎circular. No matter how it is phrased, it can always be boiled down to: if God exists then he is ‎necessary, and if God is necessary then he exists. The word ‘necessary’ is sometimes replaced ‎with ‘the greatest possible being’ or some variation, but the frame of the argument is always ‎circular: if God exists then he is like this, and if God is like this then he exists.‎

Anselm originally presented the Ontological Argument as follows:‎

‎1. By definition, God is a being than which none greater can be imagined.‎
‎2.‎ A being that necessarily exists in reality is greater than a being that does not necessarily ‎exist.‎
‎3.‎ Thus, by definition, if God exists as an idea in the mind but does not necessarily exist in ‎reality, then we can imagine something that is greater than God.‎
‎4.‎ But we cannot imagine something that is greater than God.‎
‎5.‎ Thus, if God exists in the mind as an idea, then God necessarily exists in reality.‎
‎6.‎ God exists in the mind as an idea.‎
‎7.‎ Therefore, God necessarily exists in reality.‎

In its essence, this is the circular argument that if God exists then he is the greatest imaginable ‎being (point 1), and if he is the greatest imaginable being then he exists (points 2-7).‎

This was well summarised by Alvin Plantinga, who recently said that Anselm’s argument was ‎essentially that God is a being than which none greater can be conceived, but a being that ‎doesn’t even exist can hardly be thought of as the greatest conceivable being, therefore God ‎must exist. However, Plantinga rejects this argument as relatively weak since the premise, ‘God ‎is a being than which none greater can be conceived’, really means if God exists then he ‎is a being than which none greater can be conceived, which of course can’t be used to deduce ‎God’s existence.‎

However, Alvin Plantinga then proposed another version of the Ontological Argument, which he ‎considers to be stronger:‎

‎1.‎ ‎If God exists then God is a necessary being: who exists necessarily, can’t fail ‎to exist, exists in all possible worlds.‎
‎2.‎ Therefore, if it’s possible that God exists (in some possible world), ‎then God exists in the actual world.‎
‎3.‎ It’s possible that God exists (in some possible world).‎
‎4.‎ Therefore God exists (in the actual world).‎

However, this version of the argument makes the same mistake. God’s existence cannot be ‎assumed by the argument (since the argument proposes to demonstrate God’s existence), and so ‎it is entirely circular to say that if God exists then he is necessary (point 1), and if God is ‎necessary then he exists (points 2-4).‎

As another example, William Lane Craig puts the Ontological Argument as follows:‎

‎1. It is possible that a maximally great being exists.‎
‎2.‎ If it is possible that a maximally great being exists, then a maximally great being exists in ‎some possible world.‎
‎3.‎ If a maximally great being exists in some possible world, then it exists in every possible ‎world.‎
‎4.‎ If a maximally great being exists in every possible world, then it exists in the actual ‎world.‎
‎5.‎ If a maximally great being exists in the actual world, then a maximally great being exists.‎
‎6.‎ Therefore, a maximally great being exists.‎

Again, this is the circular argument that if God exists then he is maximally great (points 1-2), ‎and if he is maximally great then he exists (points 3-6). The problem here lies in premise 3: ‎‎“If a maximally great being exists in some possible world, then it exists in every possible ‎world.” This is a non-sequitur (it does not follow). If a maximally great being exists in my ‎imagination (some possible world), then it does not follow that it exists in every possible world ‎‎(including the actual world). You simply can’t define God into existence.‎

This argument has recently been popularised in a Reasonable ‎Faith video that makes the same mistake: “If a maximally great being exists in any possible ‎world then it exists in every possible world, and if it exists in every possible world then it exists ‎in the actual world.” Reasonable Faith generally produces excellent content, but this ‎argument is a non-sequitur. Regardless of how you want to define a maximally great being, if he ‎exists in the world of my imagination (some possible world), it doesn’t follow that he exists in every possible world (including the actual world).‎

I’m a big fan of both Alvin Plantinga and William Lane Craig, and so I don’t go against them ‎easily. But in the interests of critical thinking, sound apologetics, and a genuine pursuit of truth, ‎I cannot help but try to reason with my Christian brothers and sisters to test everything and hold ‎on to what is good (1 ‎Thessalonians 5:21). Love rejoices in the truth (1 Corinthians 13:6), and so we strive to put off ‎falsehood and speak truthfully (Ephesians 4:25). Indeed, we should have no greater joy than ‎when people are walking in the truth (3 John 4).‎

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