Alvin Plantinga’s Modal Ontological Argument

[o_mlly]

Alvin Plantinga’s Modal Ontological Argument

1. It’s possible that a -]Maximally Great Being (MGB)/-] black swan exists.
2. If it is possible that a -]Maximally Great Being (MGB)/-] black swan -]being/-] exists, then a -]Maximally Great Being (MGB)/-] black swan exists in some possible world.
3. If a -]Maximally Great Being (MGB)/-] black swan exists in some possible world, then it exists in all possible worlds.
4. If a -]Maximally Great Being (MGB)/-] black swan exists in every possible world, then it exists in the actual world.
5. If a -]Maximally Great Being (MGB)/-] black swan exists in the actual world, then a -]Maximally Great Being (MGB)/-] black swan exists.
6. Therefore, a -]Maximally Great Being (MGB)/-] black swan exists.

…

Seems to me that 2, 4, and 5 border on the tautological, not adding to but perhaps explicating the argument.
And certainly, the consequent in 3 does not follow from its antecedent.

 

[o_mlly]

1. If it is possible for something to not exist in any possible world, then it is impossible for it to be necessary.
2. It is possible for a world to exist in which there is no -]God/-] necessary cause.
3. Therefore it is impossible for -]God/-] a necessary cause to be necessary.

Presto! That was incredibly easy. I’m going to take a wild guess you don’t don’t accept premise #2, just like I don’t accept the premise that God is necessary.

Remembering that the truth values of a conditional and its contrapositive are equal:
Contrapositive 1) If something is possibly necessary then that same something possibly exists in any possible world.

The truth value of 1’s contrapositive appears to be merely a tautology. Therefore 1 is tautological. If I have misstated 1’s contrapositive, I welcome any restatement.
And, 2 and 3 are clearly illogical.

 

[TheCuriousCat]

Remembering that the truth values of a conditional and its contrapositive are equal:
Contrapositive 1) If something is possibly necessary then that same something possibly exists in any possible world.

The truth value of 1’s contrapositive appears to be merely a tautology. Therefore 1 is tautological. If I have misstated 1’s contrapositive, I welcome any restatement.
And, 2 and 3 are clearly illogical.

Since I am responding to Plantinga’s argument, it should be clear that I am using the same definition of God he is. He doesn’t define God as a necessary cause, so I don’t.

If you change peoples arguments to things that aren’t equivalent, you can change their truth value. Congratulations, you have learned how to create strawmen. I guess it is way easier than honestly tackling the arguments people make.

 

[TheCuriousCat]

Yes, of course, I am “misunderstanding some fundamental terms,” when you define logical reality as…

No, it isn’t true that “In logic, … [w]orlds are a global set of premises that are logically consistent.”

Perhaps in something like modal logic what you say might be proposed, but that doesn’t mean in logic generally that worlds “…are a global set of premises that are logically consistent.”

Collapsing or conflating logic, as a whole, into your preconceptions about modal logic is where you seem to fall apart without realizing it.

I’m angry now.

We are discussing Plantinga’s Modal Ontological Argument

Of course I am basing my definitions on those based in modal logic! It is dishonest to do otherwise!

I’m done wasting my time on you.

 

[o_mlly]

Since I am responding to Plantinga’s argument, it should be clear that I am using the same definition of God he is. He doesn’t define God as a necessary cause, so I don’t.

If you change peoples arguments to things that aren’t equivalent, you can change their truth value. Congratulations, you have learned how to create strawmen. I guess it is way easier than honestly tackling the arguments people make.

Now, don’t get emotional in a philosophy thread. The ontological argument only makes sense, from Anselm to Plantinga, that if God exists then His being is necessary. That is, while it may not be necessary that God exists, it is necessary that such a being if existent be non-contingent, that is necessary.

 

[inocente]

No TheCuriousCat claimed that “Worlds: In logic, worlds aren’t planets, solar systems, or universes. Worlds are a global set of premises that are logically consistent,” which is NOT correct. I merely pointed out that “In modal logic…” would have been a more accurate qualifier for the statement.

So what is your point here? Are you arguing that the Cat’s statement is true in all forms of logic? Then, perhaps YOU need to look up “propositional logic” or “classical truth-functional propositional logic” on your friend Google.

If you are trying to point that the Cat’s point IS possibly true in modal logic, then how is that different from what I wrote?

Actually, what I claimed was that the Cat’s use of the word “consistency,” that is presumed to underlie or ground logical truth, requires that necessity also be the case. So yes, logic exists iff necessity holds in all possible worlds. The Cat’s original claim was that s/he could imagine a logical world where necessity did not exist. I am merely pointing out that such a claim is untrue because any “logically consistent” world can only be “logically consistent” if that consistency is a necessary logical aspect.

Ergo, necessity must be the case in all possible worlds, even in those conceived in the realm of modal logic. Or, to use other words, the Cat’s claim regarding worlds in modal logic assumes necessity and can only be considered true if it is necessarily true. I.e., “It is necessarily true that in modal logic, worlds are a global set of premises that are logically consistent.”

The question then becomes, “In what actuality or reality is that necessity grounded?”

Cat’s original claim was that s/he had refuted Plantinga’s argument because s/he could conceive of a possible world where necessity (MGB) wasn’t necessary.

To wit:

My larger point, then, is to point out that logical consistency requires necessity, therefore all possible worlds, even those in modal logic require and presume necessity for the world to hold as logically “consistent” in that world. In what is that consistency to be grounded? Perhaps in some kind of existential necessity (AKA MGB) which makes logic itself binding and true necessarily even in the form of modal logic?

The Cat needs to answer this little issue. Relying on would-be friends to obfuscate the matter just won’t do.

I didn’t think it was complicated.

A possible world is any logically consistent state of affairs (see SEP article I linked). A state of affairs is said to be logically possible if it obtains in one possible world but not necessarily in others. A state of affairs is said to be logically necessary if it must obtain in every possible world. E.g. Mt. Everest is logically possible but not logically necessary.

 

[Peter_Plato]

I’m angry now.

We are discussing Plantinga’s Modal Ontological Argument

Of course I am basing my definitions on those based in modal logic! It is dishonest to do otherwise!

I’m done wasting my time on you.

I thought I was granting and clarifying that your point does only apply within modal logic and not logic in general? What is dishonest and anger inducing about that?

So you won’t answer my objection, I take it?

Just when we were starting to make some headway.

So you will use your “anger” as your way out of answering what needs to be addressed. No problem.

I suppose there are possible worlds where anger provides a sufficient motive for stopping discussion, but clearly not a world where anger provides anything like logical grounds for doing so.

Well, okay, you might IMAGINE a possible world where that might occur, but I would still contend that would not be a logically consistent world, i.e., not one grounded in logical possibility, unless, of course, you could demonstrate that the anger is itself reasonable – that is, consistent with or necessitated by logic.

Another way, perhaps, of asking this is whether possible (or imaginable) worlds could even be possible if they were not consistent with underlying and universal logical requirements. In other words, imaginable worlds may not, in fact, be possible merely because they are imaginable – a point which, again, you haven’t addressed.

Yes, I get that you were insisting that internal self-consistency was the sole requirement for proposing possible worlds as truly possible and not merely imaginable, but that is what you need to show, not merely presume.

 

[inocente]

No TheCuriousCat claimed that “Worlds: In logic, worlds aren’t planets, solar systems, or universes. Worlds are a global set of premises that are logically consistent,” which is NOT correct. I merely pointed out that “In modal logic…” would have been a more accurate qualifier for the statement.

So what is your point here? Are you arguing that the Cat’s statement is true in all forms of logic? Then, perhaps YOU need to look up “propositional logic” or “classical truth-functional propositional logic” on your friend Google.

If you are trying to point that the Cat’s point IS possibly true in modal logic, then how is that different from what I wrote?

Actually, what I claimed was that the Cat’s use of the word “consistency,” that is presumed to underlie or ground logical truth, requires that necessity also be the case. So yes, logic exists iff necessity holds in all possible worlds. The Cat’s original claim was that s/he could imagine a logical world where necessity did not exist. I am merely pointing out that such a claim is untrue because any “logically consistent” world can only be “logically consistent” if that consistency is a necessary logical aspect.

Ergo, necessity must be the case in all possible worlds, even in those conceived in the realm of modal logic. Or, to use other words, the Cat’s claim regarding worlds in modal logic assumes necessity and can only be considered true if it is necessarily true. I.e., “It is necessarily true that in modal logic, worlds are a global set of premises that are logically consistent.”

The question then becomes, “In what actuality or reality is that necessity grounded?”

Cat’s original claim was that s/he had refuted Plantinga’s argument because s/he could conceive of a possible world where necessity (MGB) wasn’t necessary.

To wit:

My larger point, then, is to point out that logical consistency requires necessity, therefore all possible worlds, even those in modal logic require and presume necessity for the world to hold as logically “consistent” in that world. In what is that consistency to be grounded? Perhaps in some kind of existential necessity (AKA MGB) which makes logic itself binding and true necessarily even in the form of modal logic?

The Cat needs to answer this little issue. Relying on would-be friends to obfuscate the matter just won’t do.

I didn’t think it was complicated.

A possible world is any logically consistent state of affairs (see SEP article I linked). A state of affairs is said to be logically possible if it obtains in one possible world but not necessarily in others. A state of affairs is said to be logically necessary if it must obtain in every possible world. E.g. Mt. Everest is logically possible but not logically necessary.

 

[Peter_Plato]

I didn’t think it was complicated.

A possible world is any logically consistent state of affairs (see SEP article I linked). A state of affairs is said to be logically possible if it obtains in one possible world but not necessarily in others. A state of affairs is said to be logically necessary if it must obtain in every possible world. E.g. Mt. Everest is logically possible but not logically necessary.

The key is phrase is “logically consistent state of affairs,” i.e., consistent with logic, and how that would be shown.

Another is in the term “possible world” which depends upon the requirement for what is or is not granted as “possible.” Conflating the words “imaginable” and “possible,” doesn’t do that because what is imaginable need not be necessarily or completely logically consistent.

Let me put it another way, The Cat is claiming that what is “real” or “actual” or “imaginable” in a 2D world, which isn’t itself a real or actual world, necessarily provides us with the grounds for making claims about “possibilities” in the real world.

That would tantamount to claiming that because The Cat can “imagine” or draw the following 2-D picture…

(Please Note: This uploaded content is no longer available.)

…that and that alone means such a structure is indeed logically possible in the actual world.

 

[inocente]

The key is phrase is “logically consistent state of affairs,” i.e., consistent with logic, and how that would be shown.

Another is in the term “possible world” which depends upon the requirement for what is or is not granted as “possible.” Conflating the words “imaginable” and “possible,” doesn’t do that because what is imaginable need not be necessarily or completely logically consistent.

The thread is about Alvin Plantinga’s argument, and I linked Alvin Plantinga’s paper defining what Alvin Plantinga means by state of affairs and possible worlds.

So why not read it and use Alvin Plantinga’s definitions?

 

[Peter_Plato]

1. If it is possible for something to not exist in any possible world, then it is impossible for it to be necessary.
2. It is possible for a world to exist in which there is no God.
3. Therefore it is impossible for God to be necessary.

Presto! That was incredibly easy. I’m going to take a wild guess you don’t don’t accept premise #2, just like I don’t accept the premise that God is necessary.

Let’s go back to this counter argument to Plantinga’s, shall we?

I don’t think Plantinga need accept your 2. precisely because he would claim that the very definition of MGB precludes that possibility.

His point would be that for a MGB to exist in any possible world, it would necessarily have the trait of being necessary in every possible world. That means for a MGB to be maximally great in any possible world, it would, by definition, have to be maximally great in every possible. One of the conditions for being “maximally great” would be to have necessary existence and for necessary existence to logically be ‘necessary’ it must imply, in a logical sense – even in modal logic – that it be not merely possible in every possible world, but, indeed, NECESSARY in every possible world, otherwise you aren’t logically speaking of the MGB, but something else entirely.

Again, the point being that the MGB either must exist in every possible world or be logically self-contradictory and impossible in every possible world.

 

[TheCuriousCat]

Now, don’t get emotional in a philosophy thread. The ontological argument only makes sense, from Anselm to Plantinga, that if God exists then His being is necessary. That is, while it may not be necessary that God exists, it is necessary that such a being if existent be non-contingent, that is necessary.

I’m going to take one crack at the assumption that you actually want to understand this, but I am really not in the mood for more games on this subject.

When you looked at Plantinga’s argument, you traded MGB with black swan. Black swans are by definition not necessary. I was trying to refute his argument. I used “God” in place of MGB, because clearly that is who they think that the MGB is. And gave an argument as to why it is not necessary. A fair substitution would have used the same term in both instances.

You didn’t do that. You took the conclusion of their arguments “God is necessary” into the premises of my argument and said it is invalid.

The very argument is about whether this being is necessary. He is saying his MGB is a necessary being, and I am saying it is a not necessary being, like a black swan. You have distorted both arguments with unequivalent substitutions.

 

[Randy_Carson]

Let’s go back to this counter argument to Plantinga’s, shall we?

I don’t think Plantinga need accept your 2. precisely because he would claim that the very definition of MGB precludes that possibility.

His point would be that for a MGB to exist in any possible world, it would necessarily have the trait of being necessary in every possible world. That means for a MGB to be maximally great in any possible world, it would, by definition, have to be maximally great in every possible. One of the conditions for being “maximally great” would be to have necessary existence and for necessary existence to logically be ‘necessary’ it must imply, in a logical sense – even in modal logic – that it be not merely possible in every possible world, but, indeed, NECESSARY in every possible world, otherwise you aren’t logically speaking of the MGB, but something else entirely.

Again, the point being that the MGB either must exist in every possible world or be logically self-contradictory and impossible in every possible world.

Can a world made up exclusively of contingent beings even exist? Or does this require an infinite regression?

And if at least one necessary being is required in every possible world, then we have our candidate for the MGB, do we not?

 

[Peter_Plato]

Can a world made up exclusively of contingent beings even exist? Or does this require an infinite regression?

And if at least one necessary being is required in every possible world, then we have our candidate for the MGB, do we not?

This would be the problem with assuming that what is logically possible only requires consistency within the “world” being spoken of. What is it that would ground consistency if not some kind of underlying necessity of logical coherence? Otherwise even consistency becomes a meaningless requirement and all of modal logic becomes a nonsensical endeavor.

Tethering contingency to something like the principle of sufficient reason would seem to imply the necessity, at least, of tying the possibility of anything to more than its merely being imaginable.

So, I think the idea of possibility itself must rely upon something like explicability in any possible world, otherwise even the idea of possibility becomes nonsensical.

Can any possible world be made up entirely of contingent entities? That would be a crucial question.

If any possible world could be, then that would seem to refute Aquinas’ argument from contingency because if any possible world could be made up entirely of contingent entities then why couldn’t this world that we live in be?

Clearly, if Aquinas’ argument works, then NO possible world could be because the argument, if it does work, means that there is a logical impediment to the possibility, i.e., no world could exist with only contingent entities, which is the proof that our world requires a necessary being. So what kind of being would be necessary in all possible worlds?

Again, just because we can imagine a world with only contingent things does not mean it could possibly exist, which has been my point. To claim things are possible merely because they can be imagined, is tantamount to claiming 2D optical illusions can exist in 3D or some other reality merely because they can be represented in imaged (or drawn) form. Not so simple.

 

[Peter_Plato]

And if at least one necessary being is required in every possible world, then we have our candidate for the MGB, do we not?

Or, put another way, can possible worlds actually be possible in any meaningful sense without, ultimately and sufficiently, some sort of necessary being to ground and make them possible? Why couldn’t that necessary agent be the MGB?

Even possible worlds in modal logic require the logical thought of the individual thinking about them, and that individual requires the actual world undergirding the possibility of their thinking about anything at all. Which brings us back to the contingent world within which all our thinking exists – and what it is that such a world requires in order for it to exist in the first place.

 

[TheCuriousCat]

Can a world made up exclusively of contingent beings even exist? Or does this require an infinite regression?

And if at least one necessary being is required in every possible world, then we have our candidate for the MGB, do we not?

You can not have possible worlds which contain logical contradictions. For instance, there are no possible worlds with square circles. A purely contingent world could not exist because logical necessities would be contingent in that world. A contingent necessity is a contradiction. Therefore, it isn’t a possible world.

There are necessary beings in all possible worlds, examples of non-controversially accepted necessary beings are: premises, axioms, numbers, etc.

 

[Peter_Plato]

You can not have possible worlds which contain logical contradictions. For instance, there are no possible worlds with square circles. A purely contingent world could not exist because logical necessities would be contingent in that world. A contingent necessity is a contradiction. Therefore, it isn’t a possible world.

There are necessary beings in all possible worlds, examples of non-controversially accepted necessary beings are: premises, axioms, numbers, etc.

A possible world would have to be one that is actualizable, otherwise it wouldn’t be possible.

Necessary “beings” such as premises, axioms, numbers, etc., are inert and do not actualize anything to speak of.

So what would be the necessary aspect within any possible world that would serve to actually make it possible, i.e., to possibly actualize it?

 

[inocente]

Can a world made up exclusively of contingent beings even exist? Or does this require an infinite regression?

And if at least one necessary being is required in every possible world, then we have our candidate for the MGB, do we not?

But that is what Plantinga is attempting to prove.

 

[inocente]

A possible world would have to be one that is actualizable, otherwise it wouldn’t be possible.

Necessary “beings” such as premises, axioms, numbers, etc., are inert and do not actualize anything to speak of.

So what would be the necessary aspect within any possible world that would serve to actually make it possible, i.e., to possibly actualize it?

Logical consistency. There is literature on all this.

For instance, on MGB and abstract objects: plato.stanford.edu/entries/god-necessary-being/

 

[Peter_Plato]

Logical consistency. There is literature on all this.

For instance, on MGB and abstract objects: plato.stanford.edu/entries/god-necessary-being/

Logical consistency is a necessary, but not a sufficient condition for a possible world to be actualized. If all it has is “logical consistency” and no actualizing principle, it won’t ever be actualized so what sense is there to say it is a possible world?

“Possible” implies that it is possible for that world be made actual, but if there is no possible actualizing principle within the world it will never, ever, be actual, no matter how logically consistent it is.

Again, so in what sense is it realistically a possible world? “Possible” in terms of WHAT, precisely? It can never be actualized, because nothing within that world will ever make it actual – certainly not logical consistency on its own.

It isn’t at all actualizable, because it lacks any actualizing principle whatsoever; therefore, it isn’t “possible” in any meaningful sense.

Or, put another way, a world that can never actually come to be is not a possible world at all. What it lacks is the very thing that it needs to make it possible – that which could actualize it.

Or, put another, another, way, “logical consistency” – in terms of what possible worlds may, in fact, logically require – could very well mean that an actualizing principle is required in order to maintain any “logical consistency” with possibility.

And if that “actualizing principle” is some form of self-existent being – or that which exists by its very essence (Aquinas’ Ipsum Esse Subsistens) – then Necessary Being (MGB) would be required by any and all possible worlds in order for those worlds to be “possible” in any meaningful sense.

Now, you might add the rejoinder that we can think of possible worlds without the necessity of those being actualized, but the only reason we can conceive of them as possible is because we are, in fact, actualized.

If the actualizing principle is outside the possible world, then, still, by itself, that world is not actualizable even though it can be abstractly thought of as “possible.” It is only possible if the actualizing principle outside of that world makes it possible – but that “possible” world, in that thin sense, still requires an actualizing principle. So what makes it “possible,” in that case, is the external actualizing principle, but the world itself qua world is not a “possible” one unless it exists within a larger actual world or, at least, within one which in turn has an actualizing principle within it.