I heard an argument like this:

1. God is the greatest possible being.

2. God is a necessary being, which means that God exists in every possible world (If God exists). 

3. If God exists in one possible world, God must logically exist in every possible world. 

4. Since God is the greatest possible being, it follows that every aspect of God (being possible) exists in some possible world.

5. Therefore, God exists (in all possible worlds, including ours).

I actually just structured the premises this way myself but is the same idea as an argument I heard before. 

What do you think of it?

Yeah, I've heard this one before. I don't accept the first two premises to be true. The third premise is a guess that God exists in any possible world in the first place, so I can't accept that to be true either. The rest crumbles with that flawed foundation.

(March 4, 2017 at 4:05 am)Jesster Wrote: Yeah, I've heard this one before. I don't accept the first two premises to be true. The third premise is a guess that God exists in any possible world in the first place, so I can't accept that to be true either.

For the sake of the argument, it does depend on what God you're talking about. 

As for the argument:

TheAtheologian Wrote:1. God is the greatest possible being.

2. God is a necessary being, which means that God exists in every possible world (If God exists). 

3. If God exists in one possible world, God must logically exist in every possible world. 

4. Since God is the greatest possible being, it follows that every aspect of God (being possible) exists in some possible world.

5. Therefore, God exists (in all possible worlds, including ours).

I actually just structured the premises this way myself but is the same idea as an argument I heard before.

Number 5 is a wrong conclusion. You say in number 4 that every aspect of God being possible exists in some possible world. Suppose a God is characterized by some religion as someone that can levitate. According to what you say in number 4 only the possible attributes of the God can exist, since the ability to levitate is an impossible attribute in a possible world it follows that "God" doesn't exist in a possible world, ie, is non-existent.

It's an old sleight of hand which breaks the distinction between the concept of God and God itself. It's a rabbit hole of fuzzy assumptions, hidden changes of meanings of words that is difficult to untangle, quite an ingenius trap, but not an argument for the existence of anything. My take in a nutshell - If you make it part of your concept of God that it has to actually exist in a unique fashion, you mix two separate categories of things if you will, and that leads to weird logical pathologies. It's kind of like with the set of all sets that don't contain themselves. Your concept of God is set up such that it becomes inconsistent if God doesn't actually exist in the world, and as every logician and mathematician knows, starting from a contradiction, you can logically derive anything you want. In this case you can say: look if God doesn't exist I get a contradiction there, so therefore I have proven that it exists. But the contradiction comes from you begging the question, not from reality talking to you.

(March 4, 2017 at 4:05 am)Jesster Wrote: Yeah, I've heard this one before. I don't accept the first two premises to be true. The third premise is a guess that God exists in any possible world in the first place, so I can't accept that to be true either. The rest crumbles with that flawed foundation.

The first premise is true if the theist defines God that way (after all, you can't refute a definition unless it is logically inconsistent). The second just means that since God is necessary (must exist), the existence of God implies existing in every possible world (logically impossible to not exist).

(March 4, 2017 at 3:57 am)TheAtheologian Wrote: I heard an argument like this:

1. God is the greatest possible being.

2. God is a necessary being, which means that God exists in every possible world (If God exists). 

3. If God exists in one possible world, God must logically exist in every possible world. 

4. Since God is the greatest possible being, it follows that every aspect of God (being possible) exists in some possible world.

5. Therefore, God exists (in all possible worlds, including ours).

I actually just structured the premises this way myself but is the same idea as an argument I heard before. 

What do you think of it?

1. The key point here is him existing in any possible world .And the idea there can be a greatest being . Or the assertion that a god is in anyway necessary. Oh and you can revise this argument to show god doesn't exist. Overall the seems like a rehash of Alvin the goat man and has been man handle by far better then me. But interesting none the less.

It's the same as most other logical arguments: "God has to exist, otherwise this argument won't work."

I edited my post above

(March 4, 2017 at 4:20 am)TheAtheologian Wrote: The first premise is true if the theist defines God that way (after all, you can't refute a definition unless it is logically inconsistent). The second just means that since God is necessary (must exist), the existence of God implies existing in every possible world (logically impossible to not exist).

I define an apple as a horse with bat wings and mad guitar skills. Do you accept my first premise? Shall I construct an argument about apples using this? While it may not necessarily be a flawed premise, it is a useless one if I want to make any real point with it. It should either be an obvious definition or one that I can demonstrate with previous premises. Where do we draw the line between definitions and bald assertions? This can apply to the second premise as well. I accept neither of them.

The rest of the argument also slips up at the word "possible". Theists aren't able to demonstrate the possibility of any of these things attached to that word here. Until then, this is a useless argument.

Also theists can define till doomsday I don't have to accept the definition. They can say god is x I don't have to accept it as such . And i won't without foundation for the claim.