Friday, September 18, 2009

Two ontological arguments

The following arguments are sound, but I am not vouching for them being good.
  1. (Premise) Possibly, there is an essentially omnipotent being.
  2. (Premise) Necessarily, if a is a possible state of affairs and x is an omnipotent being, then x could be at least a remote cause of a.
  3. (Premise) It is impossible to be a cause, remote or not, of one's own never having existed.
  4. Therefore, necessarily, if x is an essentially omnipotent being, then x exists in all worlds. (2 and 3)
  5. Therefore, there is an essentially and necessarily existing omnipotent being. (1, 4 and S5)
  1. (Premise) Possibly, there is an essentially robustly omniscient being.
  2. (Premise) Necessarily, a robustly omniscient being could know every proposition that is possibly true.
  3. (Premise) Nobody could know himself to not exist.
  4. Therefore, necessarily, if a robustly omniscient being exists, it exists necessarily. (7 and 8)
  5. Therefore, an essentially robustly omniscient being exists. (9 and S5)
[Minor editing - July 12, 2012]

10 comments:

Andrew said...

Let me take a stab at premise (8)...
So it seems that an omniscient being existing in one possible world would know every state of affairs in every possible world, but I don't see how that entails that that being exists in each possible world.
Perhaps knowing what goes on in a possible world does not require 'really' existing in that possible world, but instead being able to exhaustively conceive the bounds of possibility in just one possible world.
So I don't see why it isn't possible for an omniscient being to know himself as not existing in a given possible world and yet still know everything about that world (similar to the way that I know things about certain posible worlds that I don't exist in).
Maybe I am just misunderstanding (8)...most likely this is my problem.

Thanks!

James said...

I like 1 to 5. A slight concern is that, as it stands, it doesn't get us to necessary existence, since the being in question could, I guess, cease to exist in some possible world?

enigMan said...

Prof Pruss,

In (1), the possibility is presumably epistemic or conceptual? Otherwise any argument based upon it would beg the question, and so be no good (presumably).

In (2), the possibility is presumably metaphysical or actual? If so then (2) is trivial, in the sense that an omnipotent being is able to do what is actually possible, by definition (more or less). And what God can do does go beyond what we ordinarily think of as possible. But similarly, just because we think something is possible, nor does that mean that it is. (The possibility of dialetheism, of true contradictions, springs to mind:)

So I take it that (2) is, if not trivial, then false. And if (2) is (trivially) true, then the combination of (1) and (2) is, if not question-begging, then a category error (?)

James said...

In (1), the possibility is presumably epistemic or conceptual? Otherwise any argument based upon it would beg the question, and so be no good (presumably).

I know this question wasn't addressed to me, but why, if (1) refers to a metaphysical possibility, do you think the argument becomes circular?

enigMan said...

Hi James,

I think that if there is an essentially omnipotent being then all metaphysical possibilities are grounded in that omnipotence. What is really possible is what that being can do, and what that being cannot do is not really possible. But also, an essentially omnipotent being is presumably eternal and everywhere immanent, in order for it to be omnipotent.

If so, then if there was no essentially omnipotent being, there could not actually be one, because it could not then have been eternal. So I was thinking that such a being is only metaphysically possible if it actually exists. If so, then an argument for its existence from (1) would be circular because (1) would be presupposing its existence (?)

James said...

Hi EnigMan. Thanks for the response. I don't quite follow the following though

If so, then if there was no essentially omnipotent being, there could not actually be one, because it could not then have been eternal.

Could you spell it out a bit more please? The issue you raise concerning possibilities being grounded in omnipotence is interesting though. And is one I need to think about. For if this is so, i.e. if things work that way round, then on the Christian view one would presumably be committed to, say, its being metaphysically impossible for sin to go unpunished. Which seems strange.

enigMan said...

Hi; I can certainly have a go... I'm thinking, basically, that if such a being existed at all then He would exist in all possible worlds because all metaphysical possibilities would be grounded in His omnipotence. Could there be no such being and yet that being be possible? But then in some possible world there is no such being and then such a being. For such a being to be able to affect the time before He existed, there would have to be backwards causation, which I was implicitly ruling out.

Why is it strange to think that if there is a God then sin cannot go unpunished? If we think about sin by itself, wondering perhaps whether or not it will go unpunished - whether or not there is a God - then we might be tempted to think that there was a metaphysical possibility of it going unpunished - the metaphysical possibility of atheism. But if what sin really is is something that exists only because there is a God, then there is no such metaphysical possibility. To think there is such a possibility is (I think) to think of this thing called 'sin' that you know about, and of which it seems to be possible that it should go unpunished. But that is an epistemic possibility, which exists because of your ignorance of the full true meaning of 'sin' (I am here assuming theism).

Similarly, if I consider a rock, it seems to be physically possible that it should slowly decay in a meaningless, Godless world. But if God made that rock, and especially if Idealism is true, then that is not really a possibility for that rock. It is not really a physical possibility. Now, some people use 'physical' to refer to theoretical stuff, e.g. in physics. For such people it would be a physical possibility, since such a decay follows from common theories that make no mention of meaning or God. But then, such a possibility is not a metaphysical possibility, but an epistemic one. Now, some people do the same with 'metaphysical' as those do with 'physical'. But we do not lose any meaning in such ways, just our ability to communicate.

James said...

I'm thinking, basically, that if such a being existed at all then He would exist in all possible worlds because all metaphysical possibilities would be grounded in His omnipotence.

Interesting. Though, to my mind at least, this seems sufficiently deductive/contentious a claim as to constitute an alternative ontological argument rather than making Alex's first one question-begging.

Alexander R Pruss said...

Andrew:

It doesn't take much to know lots of facts of the form "p is true in w". The robustly omniscient being, however, must satisfy this property: for all propositions p, if p is possible, then possibly the being knows p. But one can only know something true. So for every proposition p that is possible, the being must be able to exist in a world in which it is true.

James:

The second argument does establish necessary existence.

enigMan:

The possibilities are metaphysical. As for question-beggingness, that's why I don't vouch for anything but the soundness of the arguments.



I do, by the way, agree that metaphysical possibilities are ultimately grounded in the power of God. But I don't want to assume this in the arguments. :-)

enigMan said...

Alex, yeah, if they're all metaphysical then I think (1) begs the question. But I also think James is right in his first comment: If the being in question was a continuant, could He not cease to exist, while a ticking clock continued to exist, because that's what He wanted when He was all-powerful and existant?