Countering the Modal Ontological Argument

Note: What follows below is a transcription of the video

Ahh the Ontological Argument, where philosophers try to define god into existence. 

This video is going to be about the modern, Modal Ontological Argument put forward by apologists like Alvin Plantinga and defended by William Lane Craig. 

This is because the original Ontological Argument put forward by St. Anselm and philosophers like Rene Descartes was refuted by philosophers like David Hume and Immanuel Kant since the original argument assumed that “existence” was a property.   You can Google that, but almost all modern apologists won’t attempt to defend that version of the argument.

So here’s the “Modal Ontological Argument” put forward by Plantinga:

1. A being has maximal excellence in a given possible world W if and only if it is omnipotent, omniscient and wholly good in W; and
2. A being has maximal greatness if it has maximal excellence in every possible world.
3. It is possible that there is a being that has maximal greatness. (Premise)
4. Therefore, possibly, it is necessarily true that an omniscient, omnipotent, and perfectly good being exists.
5. Therefore, (by axiom S5) it is necessarily true that an omniscient, omnipotent and perfectly good being exists.
6. Therefore, an omniscient, omnipotent and perfectly good being exists

Before I continue, I want to acknowledge that the first part of my criticism here is largely taken from the atheist blogger Chris Hallquist.  He writes an excellent blog I highly recommend checking out.

What makes this argument so annoying is that it’s easy to tell that there’s something wrong with it, but it’s so very hard to point out exactly what it is, and Chris was the first person I read online who highlighted exactly what was wrong with the argument and why.  I’m including a link to his refutation in the description box.

The modal argument hinges on “axiom S5” which is from a system of formal logic.  Basically, if you’re going to do formal logic, you can pick which system of it to work under, and so long as you stay consistent in that system and obey its axioms, all is well. 

For the record, there’s no problem with S5 axioms of modal logic, this is the logic of possibility and necessity.  You just have to be aware of what you’re dealing with before you draw conclusions from an argument.

The problem here is that once you start operating under S5, making certain assumptions and running with it is frankly absurd.  The argument relies on granting what sounds like a reasonable assumption that “X is metaphysically necessary” and “X possibly exists”.  The issue here is that under S5, this logically equivalent to saying “X exists necessarily “.

This is problematic because in normal argumentation we can say that yes, “for all we know, it’s possible X exists”, where X can be Leprechauns, Unicorns, Fairies, or a god.  The problem is that when in S5, if you say that something defined as “necessary” possibly exists, you may as well start this silly argument:

1. God is defined as omniscient, omnipotent, wholly good, and as something that exists in any possible world. 
2. An actual world exists.
3. Therefore god exists!

This is logically valid, but tells us nothing!

This is why Alvin Plantinga, the guy who came up with the modal version of the argument, admits that while the argument is logically valid, it doesn’t prove anything, to quote:

“Our verdict on these reformulated versions of St. Anselm's argument must be as follows. They cannot, perhaps, be said to prove or establish their conclusion. But since it is rational to accept their central premise, they do show that it is rational to accept that conclusion”

-Alvin Plantinga, "The Nature of Necessity" (1974), pg 221

Now that last bit about the argument showing it’s rational to accept the conclusion is still way off the mark, but we’ll deal with that later. What I want to highlight here is the difference in honesty between Alvin Plantinga and William Lane Craig.  At least Plantinga acknowledges this major issue and admits it.  Craig on the other hand just presents the argument and acts as if it were somehow a valid proof of a god necessarily existing in all metaphysically possible worlds.  It shows the difference between someone doing philosophy of religion, and someone trying use arguments to evangelize.

Here’s a great example to show why granting the possibility of something that is metaphysically necessary under S5 modal logic is absurd:

Most philosophers hold that mathematical truths are metaphysically necessary.  There’s something called “Goldbach’s Conjecture” in mathematics which is an unsolved problem in number theory. 

It states that “Every even integer greater than 2 can be expressed as the sum of two primes”.

It appears to be true, and has shown to hold through 4x1018 but it’s not been proven.  However, if it is true, then it would be a metaphysically necessary mathematical rule.  Because of this, we can use the modal ontological argument to show that it must be true:

1. If Goldbach’s conjecture is correct, then it is necessarily true.
2. It is possible that Goldbach’s conjecture is correct.
3. Therefore, possibly, it is necessarily true that Goldbach’s Conjecture is correct.
4. Therefore (by axiom S5) it is necessarily true that Goldbach’s Conjecture is correct.
5. Therefore Goldbach’s Conjecture is correct.

This turns any “unproven” area of mathematics that “might be true” into something that “must be true.”  That’s frankly absurd, even mathematical theories must be proven to be true, not assumed to be true until proven false.

So even on Plantinga’s much more modest claim of the ontological argument making belief in god rational or reasonable, it doesn’t actually add any extra justification to the original idea.  You may as well say that “the idea that god exists isn’t inherently contradictory, so it’s rational to believe it.”

Of course, all of this may not be enough when dealing with apologists.  Some of them are so desperate for a valid reason to believe that they may even bite the bullet on the mathematical problem and assume theories are true until proven false.  So for those folks, I have a much more fun response to the ontological argument: The Great Demon!

Note that I’m specifically using a “Great Demon” as my example for a few reasons. If we were to use the classic maximally Great Island or maximally great lion, then apologists can say that material things can't be "necessary" since we know that outside of our space-time they couldn't really exist.  I also specifically call it a "great demon" since if we called it the "evil god" then apologists throw up a semantic smokescreen and say a "god by definition is something that is worthy of being worshipped."  So we call it a great demon.

So here’s the syllogism:

1. A being has maximal depravity in a given possible world W if and only if it is omnipotent, omniscient and wholly evil in W; and
2. A being has maximal evilness if it has maximal depravity in every possible world.
3. It is possible that there is a being that has maximal evilness. (Premise)
4. Therefore, possibly, it is necessarily true that an omniscient, omnipotent, and perfectly evil being exists.
5. Therefore, (by axiom S5) it is necessarily true that an omniscient, omnipotent and perfectly evil being exists.
6. Therefore, an omniscient, omnipotent and perfectly evil being exists.

This is a pretty strong "reductio ad absurdum" defeater of the modal ontological argument, but there are a few weak objections apologists can throw at this that I want to refute before moving on.

The first objection claims that a maximally evil being is impossible since only "good" exists, and evil is defined as the "absence of good".  But this is obviously wrong for two reasons.  First is that it gets rid of the idea of morally neutral actions, which we know exist from our experience.  But more importantly, it fails because its nothing more than a bald assertion.  We could just as easily say that only evil exists and good is the "absence of evil" and have as much justification for it.

The second objection is that an omniscient being would have knowledge of an absolute "Moral Law" and as such would be incapable of evil, since it would feel "convicted" by the law, or that all beings aren't really evil, they just rationalize evil actions, but when doing something evil, they actually believe it's the right thing to do.  This objection is defeated fairly easily since we can say that evil is grounded in the nature of the great demon, so that it isn't "convicted" by an absolute "Moral Law", if it existed, but driven to violate it.  In fact we would go further to say that the perfect selfishness of the great demon means that it wouldn't be compelled to "do what is right" but rather to do what brings itself pleasure, which according to its nature is evil.  Finally we can reject the notion that people always do what they think is right, since we've seen examples of people doing things they know to be wrong and going through with it anyway.

Now if all that wasn't enough, the final point we can make is that if the modal ontological argument is sound, then we have shown that at least two omniscient, omnipotent beings exists.  But in this case, it would be the as if neither existed!

Let's start with the premise that a maximally good being would make sure that ultimately only good things would result in any actual world. Let's also start with the idea that a maximally evil being would make sure that ultimately only evil things would result in any actual world.

So if both a maximally good add a maximally evil being exist necessarily then they would cancel each other out. This is because they would both be omniscient and omnipotent, each knowing the others thoughts at all possible outcomes of any action the other would take. Because of this they would use their omnipotence to stop any action that the other being tried to enact. As a result if both beings existed necessarily than the actual world would be it as if neither existed since neither one could act in our actual world.

One way out of this problem is for an apologist to insist that only one omnipotent, omniscient being exists, but if that is the case, then the ontological argument can't be sound since it equally demonstrates that two very different kinds of omnipotent/omniscient beings could exist with no way to identify which one it is.

So that's going to conclude my counter to the ontological argument.  I hope viewers find this useful in being able to show exactly WHY the modal ontological argument is wrong, and be able to provide some entertaining rebuttals to those apologists who stubbornly try to defend this laughably bad argument.

Thanks for watching!

References:

1.) http://www.patheos.com/blogs/hallq/2013/01/the-ontological-argument-in-brief/

2.) http://plato.stanford.edu/entries/ontological-arguments/#PlaOntArg