Alvin Plantinga and the Chipmunks

Would you like to hear Plantinga's ontological argument for the existence of God?
Do I have a choice?
No. This is a very important argument. It's the only ontological argument that has never
been refuted. That's why it's called the victorious argument.
Oh, all right.
Okay. First, we define a maximally excellent being in a given possible world as one who
is omnipotent, omniscient and omni-benevolent in that world.
I'm with you so far.
Good. Secondly, we define God as a being who exhibits maximal greatness, that is to say,
he is maximally excellent in all possible worlds.
Okay.
Now, the premise of the argument is that it is possible that God exists. Therefore it
is possible that he necessarily exists. Therefore he necessarily exists. Therefore, he exists.
QED.
Huh? Obviously you are ignorant of philosophy.
You need to take a course in modal logic and it will all become clear.
This stuff makes my head hurt. You're going too fast for me.
Okay, I'll dumb it down for you. A contingent being is one who might exist in some possible
worlds but not others.
Are you talking about Everett's many-worlds interpretation of quantum physics?
No, you idiot. This has nothing to do with quantum physics. It's a device philosophers
have used for centuries to examine contingency. We're talking about all logically possible
worlds. Just shut up and listen.
Sorry.
Okay. Now, God must be a necessary being, not a contingent one. He must exist in all
possible worlds. Otherwise he wouldn't be God.
Wait a minute. Plantinga is proving the existence of God by assuming the existence of God?
No, of course not. He is saying that "if" God exists, then he necessarily exists. That's
just part of the definition of God.
Okay. Carry on.
Now, by axiom S5 of modal logic, if it is possible that God necessarily exists, then
he necessarily exists.
I must be missing something. The only things I can imagine necessarily existing are abstract
concepts such as mathematical theerums. Now,it is possible that, for example, Goldbach's
conjecture is true. Indeed, there is considerable heuristic evidence for the strong form of
the conjecture being true, based on the probabilistic distibution of primes, and the weak form of
the conjecture has been proven for all sufficiently large integers.
However, I can't just say that it is possible that Goldbach's conjecture is true, therefore
it is true. No mathematician would accept such an argument.
But the conclusion follows inevitably from our definitions, our premise and axiom S5.
Is axiom S5 universally accepted by logicians?
Well, actually, most logicians regard it as just a convenient convention for simplifying
long strings of modal operators.
But it's obviously essential to Plantinga's argument. Without it, the argument fails.
But God by definition is a necessarily existent being. If he exists at all, he must exist
in all possible worlds.
But, by the same token, since it is possible that he doesn't exist in this world, it follows
that he doesn't exist in any possible world. Therefore he doesn't exist at all. In other
words, Plantinga's premise is questionable, at best.
But for all we know, God does exist. We are epistemologically justified in entertaining
the possibility that he exists.
I think you're equivocating about the meaning of possibility. Your premise is that in all
possible worlds, it is true that there is a world in which God exists. That's just begging
the question.
Anyway, surely you're aware of the problem of evil. Even a contingent maximally excellent
being, if it's omnipotent, omniscient and omni-benevolent, is logically impossible.
And in any case, as I already said, I can't see how anything other than an abstract concept
is necessarily existent. But nobody worships an abstract concept. Well, maybe some math
geeks worship mathematics, but they don't think it can hear their prayers or grant them
three wishes. So this whole thing is an academic exercise. Plantinga is playing mental games
with premises and axioms in a closed formal system. He hasn't even begun to prove anything
about the actual world.
He doesn't claim that he has proved anything about the actual world. His position is that
belief in God is a properly basic belief, that is, it can be taken as axiomatic and
you don't have to defend it.
What? After all this, you're telling me that Plantinga doesn't find his own argument convincing,
and doesn't see the point in making it in the first place? Please tell me this is a
joke.
No wonder this so-called victorious argument has never been refuted. It's what a scientist
would call not even wrong.