Thread: Anselm's Ontological Argument for the Existence of God

Some guy called Anselm thought of this logical argument for the existence of 'God' back in the 11th century. It's certainly very original and ingenious. It's been influential since, causing a lot of headaches and engendering a lot of discussion and theorising concerning whether the argument is valid, and, if not, why not.

In my opinion this all pretty pointless, and also, with respects to various eminent philosophers' struggles with it, rather disappointing, given that the argument is invalid simply because it has a logical error - it's like hearing that a bunch of mathematicians had puzzled and theorised over a mysterious result in arithmetic for a millennium, only to find that the mystery is plainly the result of a failing to carry a 1 in an addition. To their credit, the error is rather subtle and requires some analysis to spot, but once done so it is very plain and unambiguous.

What do you think? If you can show that the argument is erroneous, bear in mind that you should also be able to point to exactly which part(s) of exactly which line(s) in the argument are wrong.

Also, the 'God' which the argument purports to demonstrate the existence of is not a specific God such as the God of the Bible or indeed what many people think of 'God' as denoting (although this was no doubt Anselm's goal). Therefore, please don't conflate this argument with a religion-specific issue, or conflate 'God' as strictly defined in the argument with common conceptions of 'God'.


Anselm's Ontological Argument

Define 'God' to be the greatest being which we can conceive.

1. The idea of God exists in the mind (we can conceive of God by definition).
2. Thus, God either exists in the mind alone, or in the mind and reality.
3. It is greater to exist in the mind and reality rather than the mind alone.
4. Thus, if God exists in the mind alone, we can conceive a greater being, which contradicts the definition of God.
5. God exists in reality.

Originally Posted by Xei

4. Thus, if God exists in the mind alone, we can conceive a greater being, which contradicts the definition of God.
5. God exists in reality.

These parts don't quite work for me. It seems to me that "God" in this sense simply means a highest or maximum power. The argument seems to assume that there is such a power simply because a bunch of monkeys can conceive of it.

Originally Posted by TimeDragon97

These parts don't quite work for me. It seems to me that "God" in this sense simply means a highest or maximum power.

Yes, that's the right kind of interpretation. What's wrong with it though? What is it exactly that you disagree with in what you quoted? Do you mean the step from 4 to 5 is suspect? That step is fairly uncontroversial. From 3, we have that either God exists in the mind alone, or God exists in the mind and reality. 4 shows that the former of these leads to a contradiction, and is false. Therefore, the latter must be the case; i.e. God exists in the mind and reality, and so clearly we have 5, God exists (in reality).

In other words, we have "X or Y" (3), and we have "not X" (4), therefore we have "Y" (5).

The argument seems to assume that there is such a power simply because a bunch of monkeys can conceive of it.

I don't see where it assumes this. Granted, it seems unlikely that our simian conceptions could somehow be used to prove the existence of God, but the argument provided seems to prove to us that this is indeed possible.

Can someone fuse my posts?

I mean, just because we can conceive of a maximum power, that doesn't automatically mean that it exists.

Yes, but the argument isn't just

1. We can conceive of God.
2. Thus God exists.

Of course, before you saw Anselm's argument, you'd have no reason to suspect that the fact we conceive of God entails that God exists. But Anselm's argument shows us that this is in fact a logical necessity.

Basically you're currently just asserting "Anselm's argument is wrong". That may be the case, but just asserting it isn't a proof of it.

Edit: by the way, though the guy makes a claim to the contrary, the videos you linked to aren't actually addressing Anselm's ontological argument, given at the top of this thread. The arguments which he's discussing and attempting to refute in those videos are actually a distinct argument - namely the ontological argument of Descartes.

Originally Posted by Xei

Of course, before you saw Anselm's argument, you'd have no reason to suspect that the fact we conceive of God entails that God exists. But Anselm's argument shows us that this is in fact a logical necessity.

How so? I really can't wrap my head around how this argument is so compelling.

Originally Posted by TimeDragon97

How so? I really can't wrap my head around how this argument is so compelling.

It's premise 3. If God exists in the mind alone as a great being, then we can simply think of something greater. Think of it in abstract terms. If you're thinking of a great car, you can think of something even better without getting into details. Or you could just think of infinity. What's better than infinity? Infinity + 1.

So if God exists in the mind alone, we can think of something better. But if God as defined by Anselm is a maximally great being, existing in the mind alone just doesn't cut it. Therefore, it must also exist in reality, since it's greater to exist in both (P3).

Originally Posted by BLUELINE976

So if God exists in the mind alone, we can think of something better. But if God as defined by Anselm is a maximally great being, existing in the mind alone just doesn't cut it. Therefore, it must also exist in reality, since it's greater to exist in both (P3).

Why not? I don't get that. The argument makes the assumption that a maximally powerful being exist simply because we can conceive of one. It basically says, "I can conceive of a maximally great being. If it's maximally great, it can't only exist in my mind. Therefore, it exists." Even if that makes logical sense, who's to say we can conceive of a maximally great being? If it is maximally great, wouldn't have abilities and properties that we can't even comprehend? Abilities and properties that, upon seeing them, our puny monkey brains would explode or melt from sheer greatness?

And Xei, you come across as sarcastic in that post....

BTW, did either of you watch the videos I posted?

Here is a version of God that I found interesting.


Conversation with God. By The Ragged Trouser Philosopher

Got the link to work, at last.
Ragged Trousered Philosopher

Originally Posted by TimeDragon97

How so? I really can't wrap my head around how this argument is so compelling.

Just in the same way that any valid logical argument is compelling... it takes some definitions, and by a series of small logical steps, all of which seem indubitable, derives a conclusion. You accept that logical arguments are compelling, right..? It's compelling in just the same way that the following is a compelling argument that if x divides by y, and y divides by z, then x divides by z:

1. x divides by y. (By definition).
2. There exists a number, call it 'a', such that x = a*y. (From 1, and the definition of 'divides').
3. y divides by z. (By definition).
4. There exists another number, call it 'b', such that y = b*z. (From 3, and the definition of 'divides').
5. Therefore, x = a*b*z. (From 2 and 4).
6. Therefore, there exists a number, call it 'n', which is equal to a*b, such that x = n*z. (From 5).
7. Therefore, x divides by z. (From 6, and the definition of 'divides').

If you believe in the very simple steps of logic used in this argument, then you simply can't deny the conclusion. If you did deny the conclusion, you would have to point out which step is the flawed one. In just the same way, Anselm's argument uses a definition and a few very very small and seemingly indubitable logic steps (like deducing "Y" from "X or Y" and "not X") to reach a conclusion. It's compelling because the individual steps are compelling, and when taken in sequence, they compel you to accept their outcome.

I'm particularly interested in what theists make of this argument, by the way.

It wasn't sarcastic at all. If you read it, though, it addresses what you said to me and you have just repeated to Blueline. The weak ontological argument you've repeated is not the argument in this thread. For example, you complain that the argument "assumes that we conceive of a maximally great being". If you read the argument, it is clear that it doesn't make such an assumption. It defines God as the greatest conceivable being. Point 1 - that the idea of God exists in the mind - is therefore true by definition. The bit in brackets explicitly explains this.

I edited a previous post with a little response about the videos.

Originally Posted by Xei

1. The idea of God exists in the mind (we can conceive of God by definition).

Fair enough.

2. Thus, God either exists in the mind alone, or in the mind and reality.

I'll give you that.

3. It is greater to exist in the mind and reality rather than the mind alone.

What is meant by "greater"?

4. Thus, if God exists in the mind alone, we can conceive a greater being, which contradicts the definition of God.
5. God exists in reality.

This is where the argument really falls apart. Like the videos state, you're basically saying God exists by definition.

But we've pretty much come to a standstill at this point. We should wait for other members' thoughts on this.

The argument really doesn't say 'God exists by definition'. None of the logical steps say that. Step 4 clearly follows from step 3, and from the definition of God. And step 5 follows from step 2, which says God exists in the mind alone or God exists in the mind and reality, and step 4, which says God does not exist in the mind alone. Which of these logical steps is wrong?

I don't think the definition of 'greater' is a problem. In any case there are several definitions of this word which make the argument unambiguously work. For instance, define greater to mean 'having larger domains of existence'. The difference between existing in the mind and reality, and existing in the mind alone, is, obviously, existing in reality or not existing in reality: and clearly the thing which exists in reality has a larger domain of existence. Or you could define greater to mean 'capable of inspiring the greatest fear'. Obviously something which really exists is capable of inspiring greater fear than something which is just a concept in your head.

The argument is basically gibberish. It doesn't make sense at all. The faulty logic happens at step 4. Just because a word is poorly defined doesn't make it true. The argument assumes that because a god can't exist in just the mind due to it's definition, it must exist. However, that is a faulty assumption.

Neither of those is Anselm's argument though. I mean, I know the first one is supposed to be analogous rather than exactly the same, but it isn't - it doesn't have the same logical structure at all. So your attempt to show that the argument can't possibly work... didn't work. You actually rebutted Decartes' ontological argument (the argument featured in the videos above), which is different.

Originally Posted by Alric

The argument is basically gibberish. It doesn't make sense at all. The faulty logic happens at step 4.

What precisely is wrong with step 4? Isn't it a trivial consequence of step 3?

The argument assumes that because a god can't exist in just the mind due to it's definition, it must exist. However, that is a faulty assumption.

I disagree. The argument doesn't assume this at all - it's the result of a simple, indubitable logical inference. You forgot about step 2; you've already agreed that either God exists in the mind alone, or God exists in the mind and reality. You also agree that God can't exist in the mind alone. Therefore you must agree that God exists in the mind and reality.

What you're currently doing is analogous to saying that you know that your friend went to holiday in France or Germany, and you also have proof that your friend didn't go to Germany, but you refuse to concede that your friend is in France.

Like I said, the argument doesn't make sense because it is based on a poorly defined definition. Lets try this.

Define 'fukshit' to be the greatest catastrophe which we can conceive.

1. The idea of fukshit exists in the mind (we can conceive of fukshit by definition).
2. Thus, fukshit either exists in the mind alone, or in the mind and reality.
3. It is greater to exist in the mind and reality rather than the mind alone.
4. Thus, if fukshit exists in the mind alone, we can conceive a greater catastrophe, which contradicts the definition of fukshit.
5. Fukshit exists in reality.

According to your argument you must believe that fukshit is a real catastrophe that exists in reality. That is the exact same structure as your argument for god, yet clearly if fukshit really existed it would have killed us all, since I image the greatest catastrophe possible would wipe out the entire universe. Also, I just made up the word and it is utterly meaningless.

Your argument holds no ground in logic, because the definition is poorly picked.

Here is another one.

Define 'Alric' to be the greatest poster which we can conceive.

1. The idea of Alric exists in the mind (we can conceive of him by definition).
2. Thus, Alric either exists in the mind alone, or in the mind and reality.
3. It is greater to exist in the mind and reality rather than the mind alone.
4. Thus, if Alric exists in the mind alone, we can conceive a greater being, which contradicts the definition of Alric.
5. Alric exists in reality.

So now I am the greatest poster in reality right? Your argument just proved it. Oh wait, your 'argument' doesn't even attempt to address me being the greatest poster. It assumes I am from the start, and then just proves I exist, then since I exist the assumption of me being the greatest poster must also be true. Like I said, the argument doesn't even make sense.

How about this?

1. A unicorn is the most awesome horse.
2. It is more awesome to exist than not to exist.
3. Unicorns are most awesome therefore unicorns exist.

or how about

1. God is the greatest possible being.
2. It is impossible to create the universe without first existing yourself.
3. Doing the impossible is greater than doing the possible.
4. Creating the universe while not existing is a greater accomplishment than creating the universe while existing.
5. God does not exist.

Anselms Argument tries to logic, but doesn't quite make it.

While you've elaborated on how that logic can lead to some pretty unlikely scenarios (that second one in particular ;3) it hasn't gone into specifics like the question is asking:

Originally Posted by Xei

bear in mind that you should also be able to point to exactly which part(s) of exactly which line(s) in the argument are wrong.

I'll have a stab at something that just doesn't quite sit right; the IDEA of God exists in the mind, but I don't believe that fully translates into the essence of God existing in the mind, just the idea of such a thing being conceived. In #2 it's pulled some strings with me by telling me God itself exists in the mind, not merely the projected idea of it, which I don't see being the exact same thing. The mandelbrot fractal as an idea in my mind is different than the actual fractal as if it were to exist and be zooming in precisely in my mind as a reality-bound model of it would, unless I'm dumbing myself down too far.

At this point that's really the only hangnail I can tug at. While it's implied that the idea of God is the same as God, I don't think the mere idea of a 4th dimensional object is the same as a real 4th dimensional object. If I'm highly underestimating the power of "the idea" of something in my sleep deprived state(which I'm pretty sure that I might be) then I'll admit I have nothing else just yet~

Originally Posted by Spenner

I'll have a stab at something that just doesn't quite sit right; the IDEA of God exists in the mind, but I don't believe that fully translates into the essence of God existing in the mind, just the idea of such a thing being conceived. In #2 it's pulled some strings with me by telling me God itself exists in the mind, not merely the projected idea of it, which I don't see being the exact same thing. The mandelbrot fractal as an idea in my mind is different than the actual fractal as if it were to exist and be zooming in precisely in my mind as a reality-bound model of it would, unless I'm dumbing myself down too far.

At this point that's really the only hangnail I can tug at. While it's implied that the idea of God is the same as God, I don't think the mere idea of a 4th dimensional object is the same as a real 4th dimensional object. If I'm highly underestimating the power of "the idea" of something in my sleep deprived state(which I'm pretty sure that I might be) then I'll admit I have nothing else just yet~

I made this post on the first page, which I believe is essentially pointing out the essence of the problem in much less confident terms?

I had it undeleted because... well, I shouldn't have deleted it.

I wasn't trying to reproduce the argument exactly, or even it's structure exactly. That's kind of how analogies work. I couldn't very well copy/paste the argument and say "doesn't that sound silly?" now could I? They are both the same KIND of argument, and illustrate the absurdity of that KIND of argument. It was a basic attempt to show that one cannot argue something into existence, or can you not refute that I have just proven that not only must unicorns exist, but that god must also not exist.

Another particular flaw in Anselms argument is thus: what if we can conceive of something greater than could possibly exist? or what if I could conceive of a god greater than your god? You see, the mind can conceive of impossibilities. We can even visualize them. This being a lucid dreaming forum, you should be aware of this. I have had a dream before where I conjured an orb of earth energy. It seemed to radiate stone. Make sense of that. In this sentence, I put forth the concept of the squircle, a square circle, which is simultaneously conceivable and impossible. Are you following me? It's not impossible then to imagine a being so great that it can completely ignore all the rules of logic and causality. That is, it is not impossible to imagine the impossible.

Granted, it would be impossible for a being greater than the greatest POSSIBLE being to exist, but such an impossible being would be conceivably greater than his possible counterpart, and even greater still if he could accomplish everything his possible counterpart could while still not existing. Being able to ignore logic is a pretty great (and convenient) ability.

It is also possible that the greatest possible being is Larry the mailman. Sure, we can conceive of greater beings, but Larry is the greatest POSSIBLE. Larry just happens to live on an imperfect world, in an imperfect universe, and he's the best this universe could possibly offer. Any being beyond Larry in greatness is just beyond what the universe could possibly offer. Is Larry god? If god is defined as "the greatest possible being" then by that definition, Larry the mailman is god. Should I let him know?

Originally Posted by Alric

Like I said, the argument doesn't make sense because it is based on a poorly defined definition. Lets try this.

Define 'fukshit' to be the greatest catastrophe which we can conceive.

1. The idea of fukshit exists in the mind (we can conceive of fukshit by definition).
2. Thus, fukshit either exists in the mind alone, or in the mind and reality.
3. It is greater to exist in the mind and reality rather than the mind alone.
4. Thus, if fukshit exists in the mind alone, we can conceive a greater catastrophe, which contradicts the definition of fukshit.
5. Fukshit exists in reality.

According to your argument you must believe that fukshit is a real catastrophe that exists in reality. That is the exact same structure as your argument for god, yet clearly if fukshit really existed it would have killed us all, since I image the greatest catastrophe possible would wipe out the entire universe.

I think this is a legitimate demonstration that the argument cannot be right. It does not however explain what is wrong with the argument.

Also, I just made up the word and it is utterly meaningless.

No it isn't. It means the greatest conceivable catastrophe - you defined it yourself. This comment is quite bizarre.

Your argument holds no ground in logic, because the definition is poorly picked.

Here is another one.

Define 'Alric' to be the greatest poster which we can conceive.

1. The idea of Alric exists in the mind (we can conceive of him by definition).
2. Thus, Alric either exists in the mind alone, or in the mind and reality.
3. It is greater to exist in the mind and reality rather than the mind alone.
4. Thus, if Alric exists in the mind alone, we can conceive a greater being, which contradicts the definition of Alric.
5. Alric exists in reality.

So now I am the greatest poster in reality right? Your argument just proved it. Oh wait, your 'argument' doesn't even attempt to address me being the greatest poster. It assumes I am from the start, and then just proves I exist, then since I exist the assumption of me being the greatest poster must also be true. Like I said, the argument doesn't even make sense.

This also makes no sense. You show that 'Alric' exists, but your definition of 'Alric' had absolutely nothing to do with you. That's just conflating synonyms. I cautioned against this very fallacy in my first post. 'Alric' is defined to mean "the greatest conceivable poster", and that is all that it means. Nowhere did you demonstrate that the greatest conceivable poster is the same person as you.

There is no question of "assuming that God is the greatest conceivable being" - that's all 'God' means. It's a definition. There's nothing "poor" about it. You don't need to 'assume' it any more than you need to 'assume' that x divides by y, in the proof above. If it makes you happier you can replace all instances of 'God' with 'X', or even just with "the greatest conceivable being".

Originally Posted by SuperOhm

I wasn't trying to reproduce the argument exactly, or even it's structure exactly. That's kind of how analogies work. I couldn't very well copy/paste the argument and say "doesn't that sound silly?" now could I? They are both the same KIND of argument, and illustrate the absurdity of that KIND of argument. It was a basic attempt to show that one cannot argue something into existence, or can you not refute that I have just proven that not only must unicorns exist, but that god must also not exist.

I guess for the time being I'll accept that unicorns exist. As to your second argument, I deny point 3 - that doing the impossible is greater than doing the possible. By definition there are no actions which involve doing the impossible. Therefore you cannot apply a predicate (like greater than) to these actions.

It is possible to reproduce its structure. Alric did it.

Another particular flaw in Anselms argument is thus: what if we can conceive of something greater than could possibly exist?

Anselm's argument demonstrates that the greatest conceivable thing does exist, and anything which does exist must possibly exist, so this is not the case.

It is also possible that the greatest possible being is Larry the mailman. Sure, we can conceive of greater beings, but Larry is the greatest POSSIBLE. Larry just happens to live on an imperfect world, in an imperfect universe, and he's the best this universe could possibly offer. Any being beyond Larry in greatness is just beyond what the universe could possibly offer. Is Larry god? If god is defined as "the greatest possible being" then by that definition, Larry the mailman is god. Should I let him know?

Can Larry fly? If not, I can conceive a greater being, thus Larry cannot be God.

It isn't a logical argument, it is a play on semantics masquerading as a logical argument. Everyone can tell at a glance that argument is wrong, but it is hard to show where the logic goes wrong, and the reason is because it isn't a logical argument in the first place. The error isn't in the logic but in the word play.

The issue comes entirely from the definition being used. The definition is extremely poorly defined, and it on purpose because it needs to be defined in exactly that way or the argument falls apart. If you define God as the creator of the universe for example, the argument doesn't work. There is a ton of flaws in the argument though, all going back to how it is defined, then manipulating the definition to get the results you want.

Probably the strangest is that god is defined by what we can convince. Meaning by definition God can't be greater than our comprehension, and is limited by our imagination. In fact it is entirely defined as an imaginary concept in the minds of men, and he can not exist without us. Which is ironically true since we just made him up, but it goes against what the argument claims.

Again you're just conflating synonyms. "The argument doesn't work if you define God to be the creator of the universe" is a nonsensical criticism, because 'God' is not defined to be the creator of the universe and there's no reason it should have been. Are you telling me that the maths argument above is also wrong, because "it doesn't work if you define y to be the number which divides by x instead of x dividing by y"? Of course it won't work - that's because you've changed it into a totally different and flawed argument. The same applies to your criticism that "God is defined by what we can conceive". Yes, it is. So what? If you really can't move past the homonymy here, I seriously suggest you remove all references to 'God' in the original argument and either replace them with something like 'G' or even just 'the greatest conceivable being'.

There is nothing wrong with defining something and then determining whether it exists or not. For instance, you can define S to be a finite set of all prime numbers, and then "manipulate the definition" to show that S does not exist. Or you can define p(N) to be a prime factor of a number N, and show that p always exists.

Any unsound logical argument, being a sequence of propositions stated or inferred from previous propositions, can be shown to go wrong at some specific statement or inference. If there were no such point, the argument would, simply, be sound, and its conclusions correct.

There is nothing wrong with defining something and then determining whether it exists or not. For instance, you can define S to be a finite set of all prime numbers, and then "manipulate the definition" to show that S does not exist. Or you can define p(N) to be a prime factor of a number N, and show that p always exists.

For the record, numbers and sets do not exist the same way that people and cars exist. To be fair, it is said that gods, if they exist, would exist in a unique way as well (unlike numbers or cars).