Maybe I missed it in the previous pages(and threads) of this topic, and if so I apologize, but in what peer-reviewed journal was this particular proof of God published, and what were the responses of the peers?
Charles Hartshorne’s work is too massive to list. But his first peer review article on this topic was published in 1944: “The Formal Validity and Real Significance of the Ontological Argument,” *The Philosophical Review * 53 (May, 1944), 232-240. He later modalized the argument in a 1962 book: The Logic of Perfection (La Salle, Illinois: Open Court Publishing Co., 1962). Following that, he published numerous times, but most significantly, “Is the Denial of Existence Ever Contradictory?” The Journal of Philosophy 63 (February, 1966), and “Rejoinder to Purtill,” The Review of Metaphysics 21 (December, 1967).
Alvin Plantinga is a giant. He is universally recognized as one of the greatest 20th century philosophers and still going strong. Way too much to list. Here is his curriculum vitae:
http://id-www.ucsb.edu/fscf/library/plantinga/cv.html
Every peer that I am aware of (including critics Stoebenauer and Suber) acknowledge that the argument is valid, though not necessarily sound. Trent Dougherty, the English philosopher, is the only prominent peer I know of who changed his mind upon seeing it. He wrote, “Since all efforts to show that the concept of God is contradictory have failed heretofore I conclude, somewhat reluctantly, that God exists.”
Please do correct me if I’m wrong: aren’t all conclusions contained in the premises for all proofs ever?
What if I argued against the axiom of choice but for Zorn’s lemma? (I do not know the history behind this, why was Zorn’s lemma proposed?)
I think of it like this: Is it possible that the greatest possible being exists? (Sure, why not). Imagine the greatest possible being that can exist. (I’m imagining an omnipotent being). Now, since existence is greater than non-existence, the being would have to exist. (Ahhh, I see where you’re going. An imaginary omnipotent being is not as great as a non-omnipotent, but already established existence.) So if it’s possible for the greatest possible being to exist, then he MUST exist, right? (Of course…we’ve agreed that if it doesn’t exist, it can’t be the greatest possible being.) Therefore <>G=G! (Yes!) And G=God! (Uhhhh…no.)
Of course, they didn’t ask me to review any articles… 
Certainly they are. If the premises are also contained in the conclusions, then the conclusions and the premises are equivalent.
I don’t need modal logic to prove that God exists. I can prove it using plane geometry or number theory or anything else. If my strategy is to adopt assumptions equivalent to “God exists”, then the formal system I choose is just a smokescreen.
Libertarian sets out to prove that God exists. He first demonstrates that “God exists if and only if God is possible”. He then completes the circle of his proof with the assumption that God is possible. He has split “a perfect being exists” into a pair of assumptions “a perfect being exists if an only if it is possible” and “a perfect being is possible”.
While that is certainly a proof, it seems a rhetorical fallacy. He claims to have proven “God” within the system S5. Suppose he had claimed to have proven Euclid’s parallel posutulate using the other four axioms and the assumption of a proposition that implied the parallel postulate.
Would anyone agree that this was a proof of the parallel postulate?
I don’t know the history either. The only book I have with me here at work is Moschavakis’s Notes on Set Theory, and he doesn’t give any background. Regardless, that would be a wierd thing to do. Are you suggesting that some are arguing against “God exists” but agreeing that it is possible that “God exists”?
Here’s another proof, which you will unquestioningly agree is valid.
My God is the greatest possible master of Libertarian’s God.
I mean “greatest possible” in the exact same sense as Libertarian, as “being true in all possible worlds”. His proof demonstrates that there is at least one God, but nothing requires exactly one God. In fact, there might be an infinitude of Gods.
Let M be the proposition “my God exists”. He is a god be definition (“my God”), so we can say
(M -> M) & <>M
because those are both characteristics of gods.
Being the greatest possible master of Libertarian’s God means, by definition, that he cannot rule Libertarian’s God contingently. If he did, then there would necessarily to be a greater possible master of Libertarian’s God.
(“my God rules Lib’s God” -> “my God rules Lib’s God”)
And since he is a possible master of Libertarian’s God that means, by definition, that we cannot deny that he is possibly a master of Libertarian’s God, since that would be the denial of a positive ontological proposition, so:
<>“my God rules Lib’s God”
Now, I just need to prove that he exists:
[proof elided]
I can use the theorem of S5
(P -> P) & <>P -> P
to prove that Libertarian’s God exists. And I can use it to prove that my God exists as well. Finally, I can prove that my God is the master of Libertarian’s God. By definition.
Is there any flaw in my proof?
I’ve brought this up before, and have not seen it sufficiently address for those who assume that g=God and that God is good. In fact, you can show quite the opposite.
- Assume that this MOPoG has been proven.
- Assume that you can analyze the qualities of G. If you can ask the question about whether God is good, omniscient, etc., it is reasonable to ask if God has any other arbitrary quality.
- Assume that if you continuously, willingly do evil things, you are evil.
- There is a possible world consisting of only the excruciating torment of the innocent, caused by G. (The world is brought about by NE, since contingent existence depends on it.)
- Assume that the endless torment of the innocent is evil.
- In that world, God is evil.
- Since God has the same qualities in all worlds, per the previous proof, God in the prime world is evil.
The definition doesn’t make any sense because G already is the maximum possible.
Only if we knew in advance they were equivalent propositions. But there might have been a time when this was not known, and some might have chosen to believe in the soundness of one but not the other. If that’s the case, the proof that they are equivalent propositions should demonstrate to the person that the AoC is sound if they already held that the other was.
In order for the proof to work, its acolytes have to prove that existence in possible hell-worlds makes a being greater in a non-ontological sense.
I’ve read a few websites on the proof, and this is the part that its followers always skip over quickly in the hopes that nobody calls them on it.
At some point, they have to connect normal greatness with ontological greatness.
At some point, they have to say that existing in possible unjust hells makes a being greater in the normal sense.
Of course, the logical conclusion is that the greatest (normal sense) possible being exists in the greatest (normal sense) possible world.
It is patently false that being consistent with and existing in possible unjust hell-worlds make a being greater in any sense but the ontological sense than a being which exists in the greatest (normal sense) possible world.
And yet, that is exactly what those who interpret the proof as Lib does are saying, though they fervently strive to obscure it.
No, the being “G” has “ontological perfection”, which is by definition, “existing in all possible worlds”. Nothing more is claimed for “G”.
There is nothing about the proof that requires the being to be unique. There can be several greatest elements of the set of possible beings, if they each exist in all possible worlds.
You might wonder whether there is more than one being that exists in all possible worlds. I claim that there is, and I can demonstrate it.
We’ll use Lib’s proof that there is a being, call it g, that exists in all possible worlds. Now, consider the following:
G’ = “a greatest possible being, g’ who is not g, exists”
Clearly, (G’ -> G’) for the same reason that (G -> G), even without committing to the existence of g’. Likewise, by definition, ~(g = g’), whether g’ exists or not.
Now, the problematic assumption is <>G’ (just like <>G is problematic). For the same reason that you propose accepting <>G, we must accept <>G’, right? That is, if we accept <>G, we ought to accept <>G’. Otherwise, we are denying one arbitrary positive ontological proposition while insisting on another.
So, I have demonstrated that either there are no ontologically perfect beings or else there are infinitely many ontologically perfect beings.
Now, Libertarian claims merely that his God is one of these beings that exists in all possible worlds. I am making a stronger claim: no matter who his God is, it must necessarily have a master, and that is my God.
Again, just look at the definition. A god is a master of another if it rules that other god. The god I choose is, by definition, the greatest possible master of Lib’s god. The greatest possible master can’t be a contingent master, because then there would be a greater possible master. And you can’t deny that Lib’s god has a possible master, because that would be the denial of a positive ontological proposition.
It seems that constraining the number of perfect beings to one ought to be as suspicious to you as constraining it to zero. And that, among the infinitude of perfect beings, there is one that is necessarily the master of Lib’s god. It seems like you can’t deny that Lib’s god possibly has a master, because that would be as suspicious as denying that Lib’s god possibly exists.
Libertarian:
Well, that’s rather the point, isn’t it? No one who understands the argument at all claims that it’s not valid. You often refer to this “valid, but not sound” position by others; do you consider this proof sound? If so, please refute, in detail, the eminent philosophers and logicians who argue that it is not sound.
I can’t buy this. Modal logic, or any kind of logic, deals only with statements. Not beings. If nothing else, you’re guilty of being imprecise, which is pretty damning in my eyes.
You also have yet to give a meaningful answer to the question of what it means for one being to be greater than another. How do we know that I am not the greatest possible being?
I’ve addressed that here:
http://boards.straightdope.com/sdmb/showthread.php?p=4645062#post4645062
I’ve done that in quite some detail. It goes round and round. If you want more, you’ll have to read some of Plantinga’s and Hartshorne’s books and papers. I gave you a list.
Sounds lot like a distinction without any difference to me. Are all Gs the same? How could we decide?
You have a strange notion of “greatest”.
But the G in question is already the greatest possible. Are you suggesting something greater than greatest?
That doesn’t apply here because the “reatest possible” slot is already filled.
With no idea what “greatest” even means, how do we know it implies uniqueness?
How do we know there is a ceiling on greatness? What is the greatest possible number? What is the greatest possible fruit (starfruit - if you ask me)? What is greater than the greatest possible being? How about 2 of the greatest possible beings joining forces? Greatest is subjective. Why should we assume that there is ever anything that can’t be improved upon? Why can’t potential greatness be infinite, thereby ruling out the possibility of “greatest”, and replacing it with an infinite series of beings that are “greater”? If existense is infinite and boundless, then there is no need to assume that there can ever be a greatest anything. . . .
To me the greatest possible being is a rock in a box. How is that wrong? How can you prove an objective greatness? I don’t think you can. . .
Dalovin’ Dj
That’s one of the problems I’ve had with this argument. Maybe it’s in here somewhere and some kind soul can point it out to me, but I’ve never seen any sort of rational explanation of what ‘ontological perfection’ means.
Lib, if you’re still reading this, do you believe that the MOP proves the existence of omnipotence?
definition I’ll throw in the pot…
Infinite selection given infinite subject to de-selection.
Is a being like God, who is defined as eternal, even subject to de-selection?
So the question is, how does a being become subject to de-selection? How is this property of greatness falsified?
A falsified being would be greater than a being that is not falsified? Eh? I mean, at least for itself? You would think that the greatest possible being would KNOW that it’s the greatest possible being, know how to falsify it, and know how to tell the difference between itself and ALL POSSIBLE beings of lesser stature in terms of this greatness scale.
Because, if it doesn’t know, cannot prove it’s own greatest-ness, then first I have to ask whether greatness of being includes awareness of existence… because if it doesn’t, it is a synonym for existence. Secondly, I have to ask that since it nor anybody else can know whether it is or is not the greatest being… then maybe I’m the greatest possible being, or maybe you’re the greatest possible being.
Which comes back to falsification.
If you define being as something other than a synonym for existence (aka. existence exists, being = existence , being exists)
Like… umm… maybe something that is AWARE that it exists…
Then you can start the process of what falsifies this beings greatness per the definition provided above.
I think we can scrap ‘greatest possible existence’ (too subjective) and just allow that NE is proven by definition, if not the existence proof (which is arguably redundant). However to believe that NE is omnipotent and/or sentient still requires blind faith.