Explain the ontological argument to me

During a philosophy course last semester, the professor mentioned an argument for the existance of God called the Ontological Argument. I don’t think I understood him correctly, because it sounded to me like, “I can imagine a god, and capital G God is even more awesome than what I’m imagining, therefore God exists”.

No disrespect to all those ancient philosophers, but- and I’m saying this as a theist- that is possibly the most stupid argument I have ever heard, ranking up there with “Because I said so” and “I know you are, but what am I?”
I mean, the Prof said it was around for nearly two millenia before someone disproved it, so there must be more to it than that, right?

No, that’s pretty much it. Most versions also assume existence as a predicate. That way, since God is the greatest thing possible, and existing is better than not existing, God must really exist or it wouldn’t be the greatest!

I think the alternative is even more elegant. Assuming existence is indeed a predicate, a God who could create the Universe without even existing is even greater than a God who needs to exist to perform that miraculous feat!

It has been pointed out that the same God-exists-by-definition argument could be used to prove the existence of a perfect island, or a perfect horse turd, or a perfect anything. Yet such things almost certainly do not exist, except in the sense that the Platonic forms “exist.”

Another flaw in the ontological argument: Who says God is perfect? I don’t think the Bible says so anywhere. Seems to me a being Who created and rules the Universe would qualify as God, even if He were not a Perfect Being.

And, the ontological argument shares the same shortcoming of all the “proofs” in what is called natural theology: Even if accepted, it proves nothing beyond God’s existence. It proves nothing else about God. It does not prove any other point of religious doctrine. It offers no grounds to choose between Catholicism and Protestantism, or between Christianity and Islam, or between any traditional revealed religion and a purely philosophical theism or deism. You really can’t, from reason alone, infer the doctrine of original sin, or salvation through Christ’s substituted sacrifice, or anything else that distinguishes Christianity from other faiths.

I once did a comic using exactly this strategy to prove the existence of a perfect pile of shit. Glad I’m not alone :slight_smile:

True, but it does “prove” the existence of some perfect being. Except that its interpretation of the word perfect is far from accurate.

Well, no, the ontological argument is only a thousand years old, being first formulated by Avicenna. And it was rejected (if not disproven) by St. Thomas Aquinas, only a couple of centuries later. Immanuel Kant is credited with disproving it, by rejecting existence as a predicate, in his Critique of Pure Reason, 1781.

Anselm’s ontological argument was the first one to come to mind for me; but wiki says Avicenna beat him to it. Ontological argument - Wikipedia So it’s been around for a little over 1000 years; and disproved or not people still try to use it.

As for there being more too it, there is usually some vigorous handwaving to connect this defined-into-existence god to the god the handwaver worships. But that’s pretty much it.

Edit: Wow, some other people post fast…

And “perfect being” does not necessarily mean “supreme being.”

Here’s one formulation (as found on the Wikipedia page):

  1. God is something of which nothing greater can be thought.
  2. God may exist in the understanding.
  3. It is greater to exist in reality and in the understanding than just in understanding.
  4. Therefore, God exists in reality.

Here’s my own paraphrase:

  1. Think of the Greatest. Thing. Ever.
  2. If what you thought of doesn’t exist, then I can think of something even greater—namely, what you thought of, but with the additional property that it actually exists.
  3. Hence, the Greatest Thing Ever must exist, because if it didn’t, it wouldn’t be the greatest.

(One flaw in the argument is that, at least the way I’ve formulated it, it assumes that “existence” is a property that something can possess or not possess.)

Here’s one decent more detailed explanation of the argument that I found online.

Apropos of nothing, in the French film Ridicule, there’s a wonderful scene where a Catholic priest, L’abbé de Vilecourt (whose malicious character has been well established by that point), expounds the ontological argument to the court of Louis XVI, to the thunderous applause of all, including the king. (He then shoots himself in the foot, in a way I won’t spoil.)

Okay, I misremembered. I dropped out of that class half-way through the semester, so I’m not exactly an expert here.

Didn’t we have a poster here, as recently as a year or so ago, who thought the ontological proof was a valid argument?

Liberal does, if I recall correctly.

IIRC that Liberal had a version of it that he was defending recently.
Ah, here it is from 2002. I’m feeling old for some reason. A modern symbological assessment of the ontological argument for the existence of God - Great Debates - Straight Dope Message Board

My understanding of the ontological argument is that if you want it not to sound entirely retarded, you build it in an abstract form of modal logic based around “possible worlds” where “possible” and “necessary” are predicates. Then using this system you get people to accept an absurd premise based largely on the fact it sounds reasonable if you use the terms wrong.

The basic rules for this sort of logical system is that a “possible world” is roughly describable as “any world that can possibly be imagined” - which is to say, any world that isn’t itself internally contradictory. Statements may be true in it that aren’t true in our world, because each “possible world” is self-contained and not dependent on realities in the other ones.

There are then two new predicates, as noted above:
“Possible” - if something is “possible” it must be true in one or more “possible worlds”.
“Necessary” - if something is “necessary” it must be true in every “possible world”.

Okay, got all that? You might wonder what this is useful, aside from constructing the modal ontological argument in. The answer is…I’m not entirely sure. I gather that it’s an apparently useful way to visualise and describe whole categories of possibilities, without bogging yourself down with a billion if statements. For example you could say, “in every possible world where it’s raining, it’s necessary that something is getting wet”, or “It’s not possble for both Qui-gon and Luke Skywalker to be alive at the same time - so in every possible world where Qui-gon is alive, it’s necessary that luke skywalker isn’t.”

It’s relevent that I reference fictional characters - possible worlds include every possible world including fictional worlds - anything that you or anyone can imagine (so long as it’s internally consistent). Obviously, this includes reality, because there’s nothing self-contradictory about reality. Any world you can imagine, any world at all, is a possible world of its own. (And any variants of it, however similar, are also their own possible worlds, too.)

Okay, that’s the background. So what’s this have to do with the ontological argument? Let me relate it in (roughly) these terms, numbered for convenience to show where the bullshit gets inserted.

Statement 1: “God exists” is possible.

Statement 2: It’s awesomer to be necessarily existent, than to merely be possibly existent, and God’s totally awesome, so if God exists, his existence is also necessary.

Statement 3: By statement 1, there’s a possible world where “God exists” is true. Therefore, from statement 2, “God exists” is necessarily true.

Statement 4: Any thing that’s got necessary existence exists in all possible worlds, including actual reality. So, “God exists” is true in actual reality.

Statement 5: So, Christ exists.

The part that everyone points out first is the leap from Statement 4 to Statement 5 - "when did “Necessary God” become “Christ”? In a way this is the brilliance of the argument, because this is not a valid objection to the argument, and it distracts from the valid objection.

The reason why the 4/5 leap isn’t a valid point of objection is because whatever God they want, they were talking about it all along. Aside from pesky internal-contradiction disproofs, the specific god they worship does exist in some “possible world” - remember, all that means is that it’s imaginable. So they don’t have to tack on the other attributes they want later; they had them in the argument all along.

So, if that’s not the point of objection, what is? Well, it’s statement 2, obviously; the point where we concede that it’s possible to imagine a necessary god. What’s happening here is abuse of the terminology and the logic system itself. Necessary sounds awesome, and it seems like a reasonable thing to let a person imagine about their god, since we’re still talking about an imaginary god at that point. So what’s the problem?

Well, the problem is that “necessary” means something specific in this logic system - put succinctly, it means “something that cannot be imagined not to be true”. Because, remember, any imaginable world is a possible world. And anything necessary is true in every possible world. So by allowing them to take as axiomatic the innocuous-sounding statement that their God’s existence is “necessary”, you are actually conceding that it’s unimaginable that their God is nonexistent. Once you’ve conceded that, of course, the argument falls out as expected.

As should be clear now, the entire argument is based on abuse of terminology. In reality, nobody should ever accept necessaryness as true based on somebody’s say-so.

In fact, it’s trivial to prove that nothing’s existence is necessary, because it’s trivial to imagine a world that’s entirely empty - one in which nothing exists. It’s not self-contradictory, and it’s easily imaginable, so it’s a possible world. And in it, all “this or that thing exists” statements are false - so it’s impossible for any “this or that thing exists” statements to be necessarily true.

What good is the term “necessary” if nothing necessary can exist, you might demand. The answer of course is it’s useful for things that don’t exist. Remember, when it comes down to it “necessay” describes statments, not objects; it’s about truth, not existence. And there are things that are always true, in every possible universe. Here’s an example: “1 + 1 = 2” (assuming standard definitions of the symbols). It’s always true, because it’s true by definition, regardless of the universe you’re in. Much, but not all, of math is this way. The bits that aren’t are the ones which would define where you’re using euclidian or non-euclidian geomotry, for example. When you get to that point, it’s useful to have symbology to distinguish which bits of the math are always true, and which ones are dependent on the geometry of the world you’re in. And that’s where “necessary” and “possible” come into play. Not in some sleazy tricky god-proof.

The weakness of the ontological argument seems to me to be that even IF you prove a perfect being exists, the being described has almost no similarity to the Abrahamic God at all. It’s just a perfect cipher, which doesn’t seem to me to prove anything.

As I have indicated in my prior post, it depends on which formulation of the argument you’re talking about. :smiley:

The problem with the “layman’s” version of the argument, which avoids the wordplay of the modal ontological argument largely by just being retarded, is that it sets no clear bar for how perfect is perfect enough. I mean, putting aside the possible/necessary stuff, the argument is just, “Anything which is sufficiently awesome, must exist.” Like, the Fonz. And Darth Vader. And the FSM - his perfect noodlieness…

Another thing that’s always bothered me about these arguments is the assumption that “perfect being” or “greatest being” are actually objective or even meaningful terms. What does it mean for a being to be “perfect” ? What reason is there to think that there is even such a thing as an objective definition of “perfect” or “greatest” being"?

It’s saying “existence exists” then switching the word God, and all the assumed characteristics, for existence and hoping nobody notices.