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1485
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Topic
#6223
Resolved: The modal ontological argument is sound
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The participant that receives the most points from the voters is declared a winner.
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1579
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Description
INTRO
The modal ontological argument is an intriguing argument for the existence of God. Originally attributed to St. Anselm of Canterbury, Alvin Plantinga turned this argument into a modal argument for God's existence.
1. It is possible that a maximally great being exists.
2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
3. If a maximally great being exists in some possible world, then it exists in every possible world.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. If a maximally great being exists in the actual world, then a maximally great being exists.
6. Therefore, a maximally great being exists.
=== Definitions ==
Ontological argument: See above
Sound: An argument is sound if and only if it is valid and all its premises are true. If an argument is sound, then the conclusion follows
-- STRUCTURE --
1. Opening
2. Rebuttals
3. Rebuttals
4. Rebuttals/Close
Rules
1. No forfeits
2. Citations must be provided in the text of the debate
3. No new arguments in the final speeches
4. Observe good sportsmanship and maintain a civil and decorous atmosphere
5. No trolling
6. No "kritiks" of the topic (challenging assumptions in the resolution)
7. For all resolutional terms, individuals should use commonplace understandings that fit within the logical context of the resolution and this debate
8. The BOP is on Pro; Con's BOP lies in proving Pro wrong. Con may make original arguments if he wants to.
9. Rebuttals of new points raised in an adversary's immediately preceding speech may be permissible at the judges' discretion even in the final round (debaters may debate their appropriateness)
11. Violation of any of these rules merits a loss.
Round 1
Pro
#1
Thank you, con, for accepting this debate!
Intro
The ontological argument for God's existence is an intriguing argument that dates back to Anselm of Canterbury. Anselm argued that God is, by definition, the greatest conceivable being because if there was a being that could be deceived that is greater, then that thing would be God. Throughout the centuries many philosophers engaged with this argument. Although it is easily dismissed, it is a solid argument that is worth defending. In recent years, Alvin Plantinga offered his own modal version of the argument [1]:
1. It is possible that a maximally great being exists.
2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
3. If a maximally great being exists in some possible world, then it exists in every possible world.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. If a maximally great being exists in the actual world, then a maximally great being exists.
6. Therefore, a maximally great being exists.
With that, let's begin.
I. Types of Worlds and Beings
In philosophy we distinguish between 3 types of entities [2]:
- A contingent entity - an entity that could exist in some worlds, but does not have to exist others. Examples of this are humans as there is nothing about us that says we must exist (and indeed, until about 300,000 years ago humans did not exist).
- A necessary entity - An entity that must exist in all possible worlds and cannot fail to exist.
- An impossible entity - An entity that cannot exist in any possible world due to the nature of their properties being incompatible. Examples of this are a square circle, married bachelor, and an invisible pink unicorn.
In modal logic, we also distinguish between possible worlds [3]:
- The actual world - The world we live in.
- A possible world - A world that could have been but did not actualize (i.e. it is possible to live in a world in which the COVID-19 crisis never occured).
- An impossible world - A world in which could never actualize due to incompatibilities within it's properties (i.e. a world in which married bachelors exist).
With that, let's analyze the syllogism.
P1) It is possible that a maximally great being exist
When we state that it is possible for a maximally great being to exist, we are saying that there is a hypothetical world that exists in which there is a maximally great being. This maximally great being would possess all great-making properties to the maximum degree. These great making properties includes, but is not necessarily limited to, omnipotence, omniscience, moral perfection, and necessary existence. This premise is reasonable because there is nothing that is logically incoherent about such a being.
Con might argue that the possibility of an MGB is not self-evidence and requires proof; however, in modal logic, something is considered possible when their properties do not contradict each other.
P2 - P6) From possibility to necessity
P2-6 is accepted universally among philosophers as a logical continuum of modal logic. If an MGB is possible in at least one world, then we g et from possible necessary to necessary from an axiomatic modal logic S5: P3 is a statement of axiom S5 modal logic: S5: If possibly necessarily P, then necessarily P.
P2) If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
This premise follows directly from the definition of possibility in modal logic. If something is possible, there exists at least one possible world in which it is true. Thus, if a maximally great being is possible then it exists in at least one possible world. This step is uncontroversial, as it reflects the standard interpretation of modal possibility.
P3) If a maximally great being exists in some possible world, then it exists in every possible world.
P3 is a statement of axiom S5 modal logic: S5: If possibly necessarily P, then necessarily P.
P4–6): From every possible world to the actual world.
Premise 4 follows logically: if an MGB exists in every possible world, it must exist in the actual world, as the actual world is one of the possible worlds including our own.
II. Common Objections
I will now engage in some common objections.
A. The stone paradox
The stone paradox is an argument that challenges the possibility of omnipotence. The argument states "Can God create a stone to heavy that even he cannot lift it?". This objection unfortunately fails because it misrepresents what we mean by omnipotence. Omnipotence means having the maximum power to actualize any logically possible state of affairs. Not being able to do the impossible is not a limitation on omnipotence nor is it a limitation on God.
B. Maximally great islands
Some have attempted to parody this argument by pointing to the possibility of a maximally great island. The attempts to parody this argument typically fail for one of two reasons: 1) the entity is impossible and cannot exist in any possible worlds; and 2) it lacks the definition of necessary. Dr. Craig notes [5]:
“When you look at these parodies of the argument they turn out to involve things that are logically incoherent. For example, there is no such thing as the greatest possible island. You could always have more palm trees and more dancing girls on the island. And besides what makes an island great is person relative. Do you prefer an island that is a desert island remote from civilization? Or do you prefer an island that is packed with the finest resort hotels? It’s person relative. So there isn’t any such things as objective great-making properties of islands”
C. Free-will vs. All-knowing
Some have attempted to show that it is impossible for God to be both free and possess all knowledge. If God knows at time t that He will perform action A at t+1, He cannot choose otherwise, negating free will. This objection fails because omniscience and free will are compatible under several coherent frameworks. First, compatibilism holds that free will holds that God’s actions are free if they align with His perfect nature, even if known in advance. God’s foreknowledge of His choice is merely a reflection of his self-determined will and is not externally constricted. Alternatively, under a Molinist model of knowledge, God’s knowledge of His actions is contingent on His free choices, preserving both properties. Since no logical contradiction has been shown between omniscience and free will, the coherence of an MGB remains intact, supporting Premise 1 that such a being is possible. [6] Moreover, Rambam in Hilchot Teshuva writes that the knowledge of God is vastly different than the way that humans perceive knowledge:
The Holy One, blessed be He, does not know with a knowledge that is external from Him as do men, whose knowledge and selves are two [different entities]. Rather, He, may His name be praised, and His knowledge are one.Accordingly, we do not have the potential to conceive how The Holy One, blessed be He, knows all the creations and their deeds. However, this is known without any doubt: That man's actions are in his [own] hands and The Holy One, blessed be He, does not lead him [in a particular direction] or decree that he do anything.This matter is known, not only as a tradition of faith, but also, through clear proofs from the words of wisdom.Consequently, the prophets taught that a person is judged for his deeds, according to his deeds - whether good or bad. This is a fundamental principle on which is dependent all the words of prophecy.
Conclusion
The resolution is affirmed. I turn this debate over to Con. I look forward to an excellent debate
5. The Ontological Argument and Gaunilo's Island https://www.youtube.com/watch?v=jFCaC7aeHa4
Con
#2
Thanks for this debate opportunity Pro, I'm excited for a fun debate. I'm going to deconstruct the argument through replying to Pro's original arguments, that was I don't misinterpret a specific premise or anything like that.
You start off by defining your terms. I agree with pretty much everything said there so I'll skip it for now. Moving on to Premise 1:
When we state that it is possible for a maximally great being to exist, we are saying that there is a hypothetical world that exists in which there is a maximally great being.
I wouldn't dispute this premise. I'd say it's hypothetically possible for God to exist, but until some other form of proof materializes, he only exists in hypothetical worlds, which essentially means he doesn't exist. Any world you can imagine that contains God does not actually contain God because the imagined being is not real, and thus is not God. It's a caricature of God, not really him.
Con might argue that the possibility of an MGB is not self-evidence and requires proof; however, in modal logic, something is considered possible when their properties do not contradict each other.
I wouldn't argue that. I'd say there are no absolute contradictions in the nature of god, and though I believe there to be soft-contradictions that make him more unlikely, that's another debate.
Premise 2:
This premise follows directly from the definition of possibility in modal logic. If something is possible, there exists at least one possible world in which it is true. Thus, if a maximally great being is possible then it exists in at least one possible world. This step is uncontroversial, as it reflects the standard interpretation of modal possibility.
This is a premise I have a problem with, but that may be just because I don't understand your wording of it completely. Currently in this syllogism, we've only established that God exists in the world of thought, or hypothetical worlds. However this means that God isn't actually real, and it's actually God. You've established that God must exist in the real world in order to be God, but that implies that a "God" existing in thought simply isn't God rather than necessitating God's existence.
Also, this premise rests on the assumption that the universe is infinite. If you have an infinite amount of monkeys on typewriters or an infinite amount of time, then yes, they will eventually produce the works of Shakespeare. However you haven't proven that the universe is infinite in either time or space. In a set of infinite numbers, the number 12 is a necessary being, but in a set of the numbers 1-5 it is an impossible being. Likewise with the universe, the possibility of God doesn't directly translate to his existence in any possible worlds.
I do still feel like I'm missing something though, so if you could explain to me how you got from "may exist in any worlds" to "must exist in some world" that would be appreciated.
Premise 3:
P3 is a statement of axiom S5 modal logic: S5: If possibly necessarily P, then necessarily P.
I won't dispute this sentence in itself, but a lot of proponents of the ontological argument misunderstand it. I'd like to clarify that my perception of God, the God that exists in my imagination isn't actually God as per your definition. If a MGB exists in any world, it must exist in all worlds, but simply imagining God doesn't qualify as summoning a MGB into existence.
Premises 4-6:
Premise 4 follows logically: if an MGB exists in every possible world, it must exist in the actual world, as the actual world is one of the possible worlds including our own.
Once again, logically indisputable. Not going to try going after this one.
Moving on to your common objections...
The stone paradox is an argument that challenges the possibility of omnipotence. The argument states "Can God create a stone to heavy that even he cannot lift it?". This objection unfortunately fails because it misrepresents what we mean by omnipotence. Omnipotence means having the maximum power to actualize any logically possible state of affairs. Not being able to do the impossible is not a limitation on omnipotence nor is it a limitation on God.
This is less of an objection to the Ontological argument and more of just a straight up argument for atheism. I've never liked this one, and I won't use it in this debate. I completely agree, God is also bound by the laws of logic. Omnipotence is simply all powerful... within logic.
Some have attempted to parody this argument by pointing to the possibility of a maximally great island. The attempts to parody this argument typically fail for one of two reasons: 1) the entity is impossible and cannot exist in any possible worlds; and 2) it lacks the definition of necessary. Dr. Craig notes [5]:“When you look at these parodies of the argument they turn out to involve things that are logically incoherent. For example, there is no such thing as the greatest possible island. You could always have more palm trees and more dancing girls on the island. And besides what makes an island great is person relative. Do you prefer an island that is a desert island remote from civilization? Or do you prefer an island that is packed with the finest resort hotels? It’s person relative. So there isn’t any such things as objective great-making properties of islands”
I was planning to use this counterpoint, so good job predicting your opponent. Since you've already gotten us started, I'll move into my classic response to Craig. The problem he makes here is he holds the island and God to different standards. When it comes to the island, William Lane Craig says "Oh, well Morality is subjective and the best island differs from person to person", but somehow when it comes to God he believes that goodness is objective. If Morality and inherent "good" qualities are subjective, then omnipotence is subjective, omnipresence is subjective, and most importantly existence in every possible world is subjective, thus collapsing the whole argument on it's head.
Since objective morality must exist for a maximally great being to exist and the ontological argument to work, the the same argument can realistically be applied to the best island or the best cigarette pack and work the same.
Conclusion
The fundamental problem with ontological argument is not in the possibility of a MGB, but merely in its circular nature. Allow me to demonstrate by rewriting the argument slightly:
P1: God may exist
P2: If God exists, then by virtue of being God he must exist
FC: God must exist
The whole syllogism is essentially saying "If God exists, then God must exist" which is tautologically true, and gets us nowhere. Some versions of the argument (like the original by St. Anselm) rely on the premise that God exists in the theoretical world of though, but to reiterate again, that is not really God. By only existing in theory, he is not God simply because he is not real and God must be real.
Round 2
Pro
#3
Thank you, Moozer325, for your engaging reply!
Intro
Moozer325 has shown a significant misunderstanding of 5s modal logic as well as possible world semantics. I want to begin by re-iterating the MOA:
1. It is possible that a maximally great being exists.
2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
3. If a maximally great being exists in some possible world, then it exists in every possible world.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. If a maximally great being exists in the actual world, then a maximally great being exists.
6. Therefore, a maximally great being exists.
Con made some very critical mistakes in their reply and made some big concessions. I will show that by conceding P1 my opponent has essentially conceded the entire argument. With that, let's begin.
1. It is possible that a maximally great being exists.
Con unfortunately shows a significant misunderstanding of modal logic. First, my opponent concedes that an MGB is logically coherent. This is a big concession as this is the only premise my opponent can possibly challenge without conceding the entire argument. The MOA stands or falls on this premise.
Con's fatal flaw is that they misunderstand possible worlds and treats them as an imaginative scenario or mental constructs. Rather, these are rigorous philosophical models about a potential state of affairs. Thus we P1 can be rewritten as: There exists a logical state where a MGB (a being that is omnipotent, omnipresent, morally perfect, and necessary being) exists. The key of 5S modal logic is that if this being is logically coherent then it must exist in every possible state of affairs, including our own.
This isn't wishful thinking or imaging God into existence. It is a valid inference based on the rules of modal logic.By confusing hypothetical worlds with figments of imagination my opponent makes a very serious category error.
Let’s draw an analogy: possible worlds are like valid sequences in chess. Imagine we were playing a game and I could play checkmate on the next move and win the game. This is a 'possible' world because it is a logically consistent and follows the rules of chess. In the game are two possible scenarios for my next move: 1) I find the move and win the game; or 2) I don't find the move and the game continues (I could later win the game in a different manner or even lose the game because of that single critical flaw).
Similarly, a possible world n modal logic is this type of analysis. What types of worlds are logically coherent and could materialize given the rules of modal logic. If an MGB is logically coherent, then like the chess game there is only one possible scenario: The MGB materializes and is real in the actual world.
Con's attempt to dismiss possible worlds as just caricatures collapses their entire arguments. If possible worlds were just imaginations and mere caricatures then modal logic would be invalid. Indeed, possible worlds is the cornerstone of modal logic! [1]
2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
I want to clarify this premise as my opponent badly misunderstands modal logic. We did not establish that God exists in a world of thought, rather what we established is that a MGB is a logically coherent entity, meaning that there are no internal contradictions within this concept, and that could exist in a potential state of affairs. Let's continue with the chess analogy
In our game it is possible that I can checkmate you on the next move. This means that there is at least one valid sequence of moves, consistent with the rules of the game, where checkmate happens. In modal logic this is what is called a possible world - a logically coherent scenario. Now on the flip side there also exists a scenario where I do not find the move and the game continues. In both scenarios I'm not talking about imaginary chess positions or caricatures, I am talking about a logically valid state of the game based on the rules of chess.
In neither scenario do we need an infinite universe nor do we need an infinite number of monkeys typing on keyboards!
3. If a maximally great being exists in some possible world, then it exists in every possible world.
Con concedes the main point of 5S modal logic: If possibly necessarily P, then necessarily P; however, my opponent still doesn't fully understand how God is being used. We are not imagining or summoning a God into existence. We are exploring the modal logical implication if we state that an MGB is logically coherent, which my opponent agrees with.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. If a maximally great being exists in the actual world, then a maximally great being exists.
6. Therefore, a maximally great being exists.
Con concedes these premises.
Common Objections
A. The stone paradox
Con and I are in agreement.
B. Maximally great islands
Con claims Craig is applying different standards to God as opposed to a maximally great island. The problem lies in a gross misunderstanding of the two concepts. Craig does not hold God and an island to two different standards, rather he is showing the incoherence of a maximally great island. A maximally great island, and a maximally great cigarette pack, are incoherent entities that cannot exist in any possible state of affairs. If we really want to see why this is the case let's re-write the MOA:
1. It is possible that a maximally great island exists.
2. If it is possible that a maximally great island exists, then a maximally great island exists in some possible world.
3. If a maximally great island exists in some possible world, then it exists in every possible world.
4. If a maximally great island exists in every possible world, then it exists in the actual world.
5. If a maximally great island exists in the actual world, then a maximally great island exists.
6. Therefore, a maximally great island exists.
Islands and cigarette packs are both contingent entities and thus cannot be necessary and cannot be maximally great. Craig does not apply two different standards, rather he shows why applying concepts of maximal greatness to contingent entities are invalid. This argument fails because P1 is false. An MGI is in incoherent entity. Unlike a MGB, an MGI or a maximally great cigarette pack is logically incoherent.
If my opponent wants to use a maximally great island or maximally great cigarette pack as an argument then I challenge them to actually define what a maximally great island or a maximally great cigarette pack even means. Until they do that then these concepts are incoherent.
C. MOA is circular
My opponent attempts to show that this argument is circular by rephrasing this as:
P1: God may exist
P2: If God exists, then by virtue of being God he must exist
FC: God must exist
If this was the argument then it would indeed be circular; however, this is not the case. The MOA does not assume God's existence, but deduces it from the possibility of an MGB. My opponent has already conceded that it is possible. Unlike con's caricature of this argument, there is no assumption here but a mere logical inference. And once again, God is not being merely thought into existence. My opponent, once again, shows a poor misunderstanding of possible world semantics.
Sources
1. For more information on how possible worlds are treated in modal logic see https://plato.stanford.edu/entries/logic-modal/#PosWorSem
Con
#4
Con's fatal flaw is that they misunderstand possible worlds and treats them as an imaginative scenario or mental constructs.
Let me try and clarify what I mean here by "possible". I mean that God strictly "may" be possible. I never said that God must exist in some world, I only said that he "may". If God exists in one world, then yeah, he must exist in all worlds. But God could also exist in no worlds. God's possibility doesn't necessitate him living in at least one world (and then by extension all worlds).
Rather, these are rigorous philosophical models about a potential state of affairs.
Okay, so I think the disconnect here is just because you're misusing "possible". By possible, I mean that something could exist, or it could not. That doesn't necessitate the possible thing existing. If God being "possible" necessitates him being real then he is no longer possible, because something that is possible cannot be 100% real, there must be a chance that it isn't real. God is either possibly real or real, there is no in-between. This is not how you used "possible". You used it to mean that God must exist in some world. I do not concede the point that God must exist in some world. I do concede the point that God may exist in some world. I do concede that if he is real in one world then he must be real in all worlds.
There exists a logical state where a MGB (a being that is omnipotent, omnipresent, morally perfect, and necessary being) exists.
Okay, so you're just using a really weird philosophical definition of the word possible. I do not concede this point, and now I can see that I really was denying P1.
The key of 5S modal logic is that if this being is logically coherent then it must exist in every possible state of affairs, including our own.
This is the part you didn't explain very well, and I still don't quite understand. God is logically coherent, but that doesn't necessitate his existence. The Padres winning the world series is logically coherent but as a long suffering fan, I can tell you that it hasn't happened.
To define my terms even more, I'd say God is possible under my definition. It is logically coherent for God to exist or to not exist. However God is not "possible" if that means he must exist in some world.
Let’s draw an analogy: possible worlds are like valid sequences in chess. Imagine we were playing a game and I could play checkmate on the next move and win the game. This is a 'possible' world because it is a logically consistent and follows the rules of chess. In the game are two possible scenarios for my next move: 1) I find the move and win the game; or 2) I don't find the move and the game continues (I could later win the game in a different manner or even lose the game because of that single critical flaw).
Okay, I'm following your analogy so far, but I'd like to clarify that neither of those possible worlds really exists. By the end, one of them will exist, but currently I have not made a move, and thus the condition for both of those worlds to exist has not been met. These worlds are also in direct contradiction to each other, so they cannot both exist in the future. There cannot be a world where I have my cake and ate it too.
Similarly, a possible world n modal logic is this type of analysis. What types of worlds are logically coherent and could materialize given the rules of modal logic. If an MGB is logically coherent, then like the chess game there is only one possible scenario: The MGB materializes and is real in the actual world.
But in the chess game there is a choice, so why not with the MGB?
I want to clarify this premise as my opponent badly misunderstands modal logic. We did not establish that God exists in a world of thought, rather what we established is that a MGB is a logically coherent entity, meaning that there are no internal contradictions within this concept, and that could exist in a potential state of affairs.
Yes, there are no contradictions in the nature of God thus he may exist, or may not. By accepting this premise (which you did), you collapse your whole argument by accepting that God may not be real. However if you really mean that God must exist in some world and that's how you define "possible", then you have yet to back it up and support it. I haven't yet seen how God must exist in some world. The key word in this quote is could.
In our game it is possible that I can checkmate you on the next move. This means that there is at least one valid sequence of moves, consistent with the rules of the game, where checkmate happens. In modal logic this is what is called a possible world - a logically coherent scenario.
But just to reiterate, possible worlds are not real worlds, correct? God existing in a possible world does not make him real as a possible world is not real. If all possible worlds exist in the real world, then the real world contains a cake being had and eaten too, which is a logical impossibility.
Now on the flip side there also exists a scenario where I do not find the move and the game continues. In both scenarios I'm not talking about imaginary chess positions or caricatures, I am talking about a logically valid state of the game based on the rules of chess. In neither scenario do we need an infinite universe nor do we need an infinite number of monkeys typing on keyboards!
Right, but only one of the worlds materialized. Because there is a possibility in God, then that necessitates a choice. The choice is between God existing and not existing. We have no way of knowing which is the real one, which world actually materialized and which one we live in.
So to close out this argument, possibility ≠ necessity. If God is possible, then he it is necessary that he may not be real, just as it is necessary that he may be real. It is not necessary for him to be actually real, or actually not real.
Islands and cigarette packs are both contingent entities and thus cannot be necessary and cannot be maximally great. Craig does not apply two different standards, rather he shows why applying concepts of maximal greatness to contingent entities are invalid. This argument fails because P1 is false. An MGI is in incoherent entity. Unlike a MGB, an MGI or a maximally great cigarette pack is logically incoherent.
But why can God be all great and an island cannot? Saying that God is necessary and islands are contingent doesn't make it so.
The MOA does not assume God's existence, but deduces it from the possibility of an MGB. My opponent has already conceded that it is possible.
I never conceded that God must exist in some world, which seems to be how you define the word "possible". I conceded that God may exist in any number of worlds, including zero worlds.
Conclusion
You either mean two things by "possible", and I still can't tell which one is really what you're using. You either mean that God could exist or not (the traditional universe), or that God must exist in some universe. If it's the first one, you've conceded the argument by admitting that it's possible that God may not exist. If it's the second one, I never conceded the point, and you now need to prove that God must exist in at least one world.
Possible worlds are not worlds based on the definition. If something is possible, then there is a chance it is not real. If there is a chance that a world will not end up being real, then it's not a real world yet, and thus if God exists in that world, then God is not real in that world. To satisfy your BOP you now have to prove that God must exist in a world that is a real world, not a possible world.
Round 3
Pro
#5
Thank you, con, for your reply!
Introduction
I want to begin by reiterating the argument and by clearing up some misconceptions that con has.
1. It is possible that a maximally great being exists.
2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
3. If a maximally great being exists in some possible world, then it exists in every possible world.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. If a maximally great being exists in the actual world, then a maximally great being exists.
6. Therefore, a maximally great being exists.
1. Understanding Possible Worlds
My opponent's misunderstanding of possible worlds is quite apparent.
I want to really try and clarify possible world semantics. Again, possible worlds are not physical realms and imaginations that are waiting to exist. As the Sanford Encyclopedia of Philosophy notes, a possible world is "maximal consistent descriptions of how reality could be—a complete specification of a possible state of affairs."[1]. In modal logic use use possible worlds to evaluate necessity. The symbolic break down of this is:
◊P: P - It is possible that p
□P - It is necessary that p.
Let's take the statement that I can checkmate con on the next move. We can break this down into the part ◊C - It is possible that checkmate occurs on the next move.
The statement 2+2=4 can be written as:
□P: 2+2=4. It is necessary that 2+2 is equal to four because it is impossible for 2+2 to equal anything but four.
In other words, there is a maximally consistent description of reality where I could checkmate you on the next move, but there is no possible maximal description of reality where 2+2 does not equal four. It simply is not possible.
When we are saying it is possible that God (MGB exists) we are saying that there exists a maximally consistent state of reality where there exists a being who is maximally great is real.
Okay, so I think the disconnect here is just because you're misusing "possible". By possible, I mean that something could exist, or it could not. That doesn't necessitate the possible thing existing. If God being "possible" necessitates him being real then he is no longer possible, because something that is possible cannot be 100% real, there must be a chance that it isn't real. God is either possibly real or real, there is no in-between. This is not how you used "possible". You used it to mean that God must exist in some world. I do not concede the point that God must exist in some world. I do concede the point that God may exist in some world. I do concede that if he is real in one world then he must be real in all worlds.
My opponent is correct that via the law of excluded middle God either exists or does not exist. The MOA states that because God is possibly necessary then He exists. This is done through 5s modal logic: S5: If possibly necessarily P, then necessarily P. [2].. I don't quite understand what my opponent means by "If God being "possible" necessitates him being real then he is no longer possible, because something that is possible cannot be 100% real, there must be a chance that it isn't real." By definition anything that is real in the actual world is possible.
As for why God can be all great but an Island cannot this goes back to the first premise of the argument.
1. It is possible that a maximally great being exists.
Essentially what we are saying is that "It is possible that an omnipotent, omniscient, morally perfect, necessary entity exists." Such a being is possible because, as my opponent has already conceded, these things are not in contradiction with one another and can coherently exist. A maximally great island is an impossible entity because such a concept is as incoherent as a square circle. Again, if my opponent wants to try and parody this argument by stating a maximally great island is possible then I challenge con to actually define what a maximally great island even is. Finally, a maximally great island is impossible because contingent beings cannot be maximally great, by definition.
Sources
Con
#6
I want to really try and clarify possible world semantics. Again, possible worlds are not physical realms and imaginations that are waiting to exist. As the Sanford Encyclopedia of Philosophy notes, a possible world is "maximal consistent descriptions of how reality could be—a complete specification of a possible state of affairs."
I completely agree with this statement, and with pretty much all the other things you said afterwards to clarify what "possible" means.
I agree that 2+2 must necessarily equal 4, as there is no other way things could be. By process of elimination we can determine that 2+2=4. However 2+2=4 is no longer "possible" because there isn't a chance that it doesn't exist, it necessarily exists. By saying that God is possible, you say that there is a chance he doesn't exist, conceding the entire debate.
A possible thing cannot go from possible to existence without removing the fog of ignorance. Using meer logic we can't make a possible being necessary, because as a quality of being possible, it must be possible that it does not exist. Otherwise it would already be a necessary being. To use an example, let's say that there is a possible apple on that table, but we can't see the table. If all we know is that it's possible the apple is on the table, then we know for a fact that it is possible that the apple may not be on the table. Thus we cannot use logic to prove that the apple must be on the table, because that would contradict what we already 100% know about the apple, that it may or may not be on the table.
When we are saying it is possible that God (MGB exists) we are saying that there exists a maximally consistent state of reality where there exists a being who is maximally great is real.
I agree, there is a possible world where God exists. Of course, that world isn't a real world, since it's an imaginary world. God existing in that world doesn't make God exist, because that world doesn't exist.
My opponent is correct that via the law of excluded middle God either exists or does not exist. The MOA states that because God is possibly necessary then He exists. This is done through 5s modal logic: S5: If possibly necessarily P, then necessarily P.
A possible necessity is a logical contradiction, it cannot exist. By being possible, something has the quality of maybe existing, and maybe not. By being necessary, something has the quality of absolutely existing, and never not existing. Something cannot have the possibility of not existing, and also not have the possibility of not existing. The possibility of existing can be defined by a number. That number cannot be 0% and also a number greater than 0%.
Essentially, you can't have your cake and eat it too. You can have your cake possibly exist while it has clearly been eaten. The cake cannot have a possibility of existing once it has been eaten. Possibility and necessity are two competing qualities that cannot be had by the same being. Thus a possible necessity cannot exist.
I don't quite understand what my opponent means by "If God being "possible" necessitates him being real then he is no longer possible, because something that is possible cannot be 100% real, there must be a chance that it isn't real." By definition anything that is real in the actual world is possible.
The word "possible" is a maybe-word, not a definite-word. "Possible" hide behind a veil of ignorance, saying that something has a chance at both existing and not exiting. The second something does exist, there is no longer a possibility of it not existing, so it is no longer "possible", it simply is.
I'll save final conclusions for my final argument
Round 4
Pro
#7
Thank you, con, for an excellent debate. I will briefly summarize this debate and why you should vote Pro.
This debate is based on the soundness of the modal ontological argument:
1. It is possible that a maximally great being exists.
2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
3. If a maximally great being exists in some possible world, then it exists in every possible world.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. If a maximally great being exists in the actual world, then a maximally great being exists.
6. Therefore, a maximally great being exists.
My opponent has conceded every premise except for premise 3. Unfortunately my opponent's continues to misunderstand premise 3 and misunderstand modal logic.
My opponent is correct that via the law of excluded middle God either exists or does not exist. The MOA states that because God is possibly necessary then He exists. This is done through 5s modal logic: S5: If possibly necessarily P, then necessarily P.A possible necessity is a logical contradiction, it cannot exist. By being possible, something has the quality of maybe existing, and maybe not. By being necessary, something has the quality of absolutely existing, and never not existing. Something cannot have the possibility of not existing, and also not have the possibility of not existing. The possibility of existing can be defined by a number. That number cannot be 0% and also a number greater than 0%.
This is not a logical contradiction but an axiom of modal logic: ◊□P → □P. ◊□P means there exists at least one possible world where P is true in all possible worlds (i.e., P is necessarily true in that world). In other words, if P can be necessarily true somewhere, its necessity holds universally.
Thus we are saying because there is at least one possible world where God is necessary, then God is necessary in all possible worlds. This is not a stretch but a basic foundational axiom of modal logic. In modal logic, necessary means true in all possible worlds, including the actual world as the actual world is a possible world.
I don't quite understand what my opponent means by "If God being "possible" necessitates him being real then he is no longer possible, because something that is possible cannot be 100% real, there must be a chance that it isn't real." By definition anything that is real in the actual world is possible.The word "possible" is a maybe-word, not a definite-word. "Possible" hide behind a veil of ignorance, saying that something has a chance at both existing and not exiting. The second something does exist, there is no longer a possibility of it not existing, so it is no longer "possible", it simply is.
Again, another woeful misunderstanding of modal logic. In modal logic possible does not mean a veil of ignorance, it means ◊P - it is true in at least one possible world. Consider the following statements:
It is possible that it will rain tomorrow
It is possible that I will win this debate
It is possible that I will lose this debate
In these statements we are not hiding behind ignorance, we are saying ◊P - it is possible in one possible world it rains, I win, or I lose. None of this is shrouded in ignorance.
Conclusion
In this debate my opponent conceded all the premises in the argument except premise 3. However, con's repeatedly misunderstood and misapplied modal logic. I've shown that going from possibly necessary to necessary is a warranted fact of modal logic.
The resolution is very strongly affirmed. Please vote pro!
Sources
Con
#8
This is not a logical contradiction but an axiom of modal logic: ◊□P → □P. ◊□P means there exists at least one possible world where P is true in all possible worlds (i.e., P is necessarily true in that world).
The problem is that P being possible does not necessitate it existing in at least one world. We've been over this, if P is "possibly real" then by definition it must also be "possibly unreal", otherwise it automatically becomes necessary. There does not have to be a world where P exists, because as you stated, P is "possible". That means that it's also a possibility that P exists in no worlds. Since P is possible, it cannot then be necessary. If something is necessary, then there is 100% chance it exists, but if it is possible, then the possibility of existence must be less than 100%. Possibility of existence cannot equal 100 and a non-100 number at the same time.
Thus we are saying because there is at least one possible world where God is necessary, then God is necessary in all possible worlds.
You have yet to support this claim. God being possible necessitates that he may not exist in any worlds. Thus you cannot say that a possible being must exist in at least one world.
Conclusion
Pro makes two big mistakes in his argument. First, he assumes that possibility necessitates existence in some world. I remind the voters that Possible worlds are not real worlds, and something existing in a possible world doesn't actually exist. From the truism that God may be possible, Pro derives that God exists in some world using this logical fallacy, the fallacy that possible things must exist in some world. Possible things (by definition) must also contain the possibility of not existing, and thus cannot necessarily exist in some world.
The second mistake Pro makes is not distinguishing possibility and necessity, and not understanding that they are mutually exclusive. Pro describes God as a possible necessity, but this is a logical contradiction. If something is possible, it's chance of existence (which I will represent as C) must be greater than 0% and less than 100%, but if something is necessary, its chance of existence is 100%.
C = 100 and 0 < C < 100
C = 100 and C ≠ 100
These mathematical statements cannot both be true
Thus Pro has already forfeited his resolution by asserting that God is possible. By stating such, he has also conceded, that it is possible for God not to exist, and thus given up the Modal Ontological arguments conclusion, that God must exist in the real world. By collapsing his argument, he has shown how the MO is not sound, and failed to uphold the resolution.
Thank you Pro for this debate opportunity, and thanks to those reading and voting.
No content
Looks like there is nothing here yet
That's what I spent the whole debate trying to understand, and you guess is still as good as mine
P2 and P3 flow from modal logic. If something possibly is necessary in one possible world then it is necessary in all worlds. This is an axiom of 5s modal logic.
P2 also seems unfounded. Just because something conceivably could exist, doesn't mean it does. There must be something I'm missing here, because I can't see how anyone could be convinced by this argument.
How is P3 uncontroversial? It's basically just stating that anything which possibly exists, does exist. Where is the logic there?
I understand your issue with the argument. For it to be sound every premise needs to be true. I believe all premises are true. P2-6 is uncontroversial. The only way to attack this argument is through P1. There are only two possible routes for con to take in this argument:
1) Show an MGB is impossible like a square circle
2) Show how an MGB leads to modal collapse.
These debates have a built in oddity:
Soundness of such a thing really can't be proven, only validity. A high level of validity, well above the base level to be sure, but still validity.
Of course to attack the soundness, the validity is the best target.
But if the setup says "valid" then it's like going for a cheap win, and will be mocked for it.
It's almost like we need a to differentiate between lowercase and uppercase Validity and Soundness.
Anyways, I'll plan on voting.
Also,
https://debate.miraheze.org/wiki/Validity_vs._Soundness
Yeah, thank you for giving me the opportunity
Thanks for a fun debate!!
No because I don't think any voters or even David are going to interpret the rules in the way you're suggesting.
Combine that with the description.
Does Rule 6 become an issue?
Okay, but saying "Resolved: The modal ontological argument is sound" isn't the same as saying the Pro side is true, it's just setting up a topic. Similar to "This house believes that..."
For The Ontological Argument to be sound, the following must be assumed:
1. It is possible that a maximally great being exists.
2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
3. If a maximally great being exists in some possible world, then it exists in every possible world.
4. If a maximally great being exists in every possible world, then it exists in the actual world.
5. If a maximally great being exists in the actual world, then a maximally great being exists.
See the issue?
The assumption in the resolution is that Pro defends the ontological argument and Con attacks it, not that they both agree to it.
Also rule 6 says no challenging assumptions in the resolution but doesn't mention the description.
Resolution/Topic: The modal ontological argument is sound
Rule 6: No "kritiks" of the topic (challenging assumptions in the resolution)
The description just defines what the argument is, accepting the debate doesn't mean accepting the argument as sound. The rules are pretty clear about that.
But it is in the debate description
"Con has to Kritik to win btw."
Why? Con is allowed to challenge the premises of the argument.
I recommend you to establish with Pro what counts as a Rule 6 violation before either posts a Round 1. That way if you disagree, it saves Pro wasting effort and this is unrated anyway so Pro is not feasibly robbed of a free win that would count towards Rating.
Con has to Kritik to win btw. Rule 6 is unfair.