I'm not a big fan of logical proofs for God, because I've never seen one bring anyone to Christ, but I do love me some philosophical sparring once in a while.
For those of you who don’t know what the Ontological Argument is it’s to say that if we can conceive of the greatest most supreme being (God) then it must exist. Hume dismantle’s this in what I think is a very simple way.
WARNING: The following is not simple.
Hume says that nothing can exist unless the opposite of it implies a contradiction. Meaning, if you can think of something in your mind, and then think of the opposite of that thing, if a contradiction arises through the conception of the opposing object then it cannot exist.
You confused me here: is he arguing that a thing can only exist if its opposite implies a contradiction, or it cannot?
Here is the argument Hume makes:
“I shall begin with observing, that there is an evident absurdity in pretending to demonstrate a matter of fact, or to prove it by arguments a priori. Nothing is demonstrable, unless the contrary implies a contradiction. Nothing, that is distinctly conceivable, implies a contradiction. Whatever we conceive as existent, we can also conceive as non-existent. There is no Being, whose existence is demonstrable. I propose this argument as entirely decisive, and am willing to rest the whole controversy upon it.”
The argument in this passage, formalized, goes something like this:
The only way to prove something a priori is if its opposite implies a contradiction.
If something implies a contradiction, then it is inconceivable.
Everything can be conceived not to exist.
4. Nothing can be proved to exist a priori.
In other words, What is impossible involves a contradiction, and what involves a contradiction is inconceivable, so what is impossible is inconceivable.
I have lived my life with the idea that God doesn’t exist, and no contradictions have arisen from that thought. God cannot exist a priori.
The main problem here is the assumption that a world without God would be indistinguishable from a world with Him. Since only one of those possibilities is true, we have not seen its opposite, meaning that we can't say, with any certainty, what that opposite would look like. The only thing you can know with certainty is that your (or my) idea regarding God's existence has no effect on the truth of the matter.
I'd suggest that a number of contradictions exist, but you haven't encountered them, or have ignored them. Why are humans self-aware? How and why is the mind distinct from the brain? Why do humans seek a greater purpose than survival? Why does altruism exist (people usually ask why evil exists, but "evil" is totally consistent with natural selection, while altruism is in conflict with it)? What caused the first effect?
...as far as this is an argument a priori, there is no absurdity in pretending to demonstrate a matter of fact by it; for when you once assume the existence of any thing as a fact, the non-existence of its cause implies a contradiction, because the non existence of the cause implies the non-existence of the effect, or of the thing assumed as a fact. Nothing, you say, that is distinctly conceivable, implies a contradiction. Is it distinctly conceivable, that there should not be a first cause of all things? The very proposition which you make a member of your syllogism, the corner stone of your logical edifice, overturns it, and establishes the necessary existence of the Deity. Whatever we conceive as existent, we can, according to you, conceive also as non-existent. Not so; we conceive of space as existent: can we conceive it as non-existent? The utmost stretch of the imagination cannot annihilate space; therefore its existence is necessary, and its non-existence implies a contradiction. So it is with the first cause or the Deity. Allow the existence of one thing, and of but a single tom, and the non-existence of its primary cause, or the deity, involves an absurdity.
Early Responses to Hume, p232
You write: "I also feel that the Kalam Argument can be used on itself. Theists argue that the universe needed to be created or at least have its events set into motion. They claim that only a being could do this, but then I ask, what set the events into motion that created the supreme being? Did this being always exist? Didn’t his existence need to be brought into motion?"
Without a deity, we have a regression problem. Every event is an effect, and must have a cause. The universe has an age, an origin event, which means it has a cause. Since that origin was the beginning of both time and space, the cause must exist outside of time and space. A being existing outside of time has no origin, and a being existing outside of space has no locality. In fact, it does not "exist" at all; it simply is. Whatever you might accept this being to be, it must exist.
