There are many issues here and I'd still like to know what's your standpoint, does any of these arguments prove anything of practical impact, or are we just dealing with logical exercise? In other words, is this argument both valid and sound or just valid?
Hi UF,
I'll try to deal with your questions, but I am really overstretching the little energy I have, so this is rushed.
For Plantinga's argument, the crux is the possibility premise. I am skeptical of his arguments for that (as is he himself, by the way), but if someone can build a good argument for metaphysical possibility, the remainder of the argument follows.
1. For one thing I can just say that it's possible that natural world exists necessarily. You can't deny it without begging the question.
That is true, but now you are talking of epistemic possibility - and that isn't enough to make the argument work, because the modal axioms only apply to identical modalities.
This thread discusses that.
David Chalmers has written
a relevant article regarding possibility and conceivability.
2. I think it's false dichotomy that god either cannot exist or he exists necessarily.
Let's take a less controversial example - assuming an accessibility relation that reaches "our kind of worlds", where maybe Hitler would have won the war, but where pigs don't fly.
Water is H
2O - and necessarily so. If it weren't H
2O, it wouldn't be water, would it? Now imagine we are unsure about this, for some reason (maybe we are only just starting Chemistry lessons). Then we'd say: "Well,
if water is H
2O, then it
necessarily is H
2O, i.e. it is so in all possible worlds - worlds in which it isn't aren't ontically possible. But if it isn't, it isn't in any possible world. So either water
must be H
2O, or it
cannot be H
2O.
With God it is the same thing. Existence needs an explanation, but we are unsure about the nature of that explanation. Yet, because in our kind of worlds existence is the case, whatever the explanation is must necessarily be the explanation. If brute existence is the explanation, then it necessarily is, and there is no place for God in any possible world. If brute existence isn't, then it won't be in any world. And likewise for God.
Why are logic and math true? Why do space, time and matter (or the substrate that enables them) exist? Why causation, why the laws of physics? Whatever the answer is, it must
necessarily be the answer.
(And whatever the answer is, it cannot be some being inside this world, inside time-space, because that would be begging the question. Brute existence cannot be itself an existent, can it? Quite apart for the conceptual loop that would imply, something within time could never create time, as it "wouldn't have the time to do so".)
But I don't see anything wrong with mere saying that it's possible that god exist without using word necessary.
There is nothing wrong with that - but the necessity follows as explained above.
3. I don't see how does it follow that introducing necessary god to every possible world somehow automatically means god is all existence.
It doesn't mean that - the implication is the other way around. God being pure existence (or the ground of pure existence) is simply classical theism (see e.g.
Thomas Aquinas' De ente et essentia, especially points 89-91). It is what we
mean when we are talking of God, and it is what the notion of MGB is trying to capture.
Anselm's ontological proof and Thomas' five ways are related. By going from e.g. moved things to their movers, one goes up the "greatness" ladder, the First Mover being the greatest thing - and likewise with all the other ways. That which "causes" existence is greater than that whose existence is caused by it. The dreamer is greater than the dream.
Maybe I'm wrong but isn't it perfectly plausible that there may be more than one necessary being? Aren't number necessary for example?
For us there are indeed many necessary beings - but what is the ground of their necessity? "Math just is", brutely? Then brute existence is necessary in a more fundamental sense - is greater than math.
4. It's just came to my mind, since we don't define as necessary, what if we formulate our premise differently, namely it's possible that it's necessary that god doesn't exist.
Yes, that is the obvious counterclaim to the possbility of the MGB. If for whatever reason there
is no final ground of existence, then there
cannot be one.
I can perfectly imagine that there may be some logical or metaphysical, and certainly physical obstacles against the concept of omnipotent disembodied mind.
Metaphysical maybe, but not logical or physical - because such obstacles could only apply to existents, to beings
subject to logical and physical laws, not to the source of such laws.
(Here I must say that Dr. Craig seems partially to disagree with me - and I don't know how he grounds logic.)
5. Even if all objections you wrote were perfectly spot on I could still cut out almost everything. We don't need omnibenevolence here, nor omniscience, nor personality.
True, the argument as given doesn't take us all the way to the Christian God. Dr. Craig makes an argument for personality based on the finite time since creation.
Or I can switch from omnibenevolence to omnimalevolence so already at this point you have to admit you can't prove omnibenevolent god using this agument because it may be used to prove god of evil too.
No, I am afraid that wouldn't work, as
omnimalevolence is a posterior notion. Given a sufficiently broad accessibility relation, a necessary being can only have prior properties.
If you really want something that may be easily imaginable as necessary I can come up with some mystical impersonal energy capable of creating universes.
Yep, that is basically what brute existence is - except that it isn't an energy, because energy would make it an existent again, requiring something greater to explain it.
However I think it's dangerously similar to quantum vacuum and we can skip word mystical completely thus reducing this case to just one nation, namely natural world may exist necessarily.
Except that the quantum vacuum is part of the explanandum, and still awaits an explanans. There is something greater than the quantum vacuum, even if it is only brute existence.
6. I still can't detect any transit between logical constructs and factual world.
The factual world seems subject to mathematical laws, and mathematics seems subject to logical laws. So logic can tell us what is necessary, contingently possible, or impossible about the world. And here it tells us that the MGB is not contingent.
Every possible world we're talking about here is just idea or concept, when we refer to actual world what we in fact mean is concept of actual world that exists as an idea in our mind.
That is true - our ideas
refer to the external actual or possible worlds, but they are not identical with them. Yet, if our ideas faithfully represent those worlds, they can give us information about them. If I put a marble in an empty bag, and then add another marble, the idea in my mind tells me there are now two marbles in the bag - and that corresponds to the truth in the actual world.
So the
concepts of such possible worlds (including the actual world) is in our mind, and if those concepts are correct, they can tell us something about the real possible worlds (again including the real actual world).