"The concept of God". I reject God as a concept. Done. If you can speak God into existence by defining it, then I can speak it out of existence by calling BS.
"It is possible for God to exist". No it's laughably impossible. Done.
The OA isn't a good argument for various reasons that others have noted above, but the possible existence of God (or Unicorns, or Colorless Green Ideas) isn't one of them.
Example:
∀(G ∈ gods . card(G) = 3) ∧ ∀(G ∈ gods . card(G) < 3)
Do you have enough control over your mind to command it to contemplate what the truth of the matter is?
Homer Simpson's version was "Could Jesus microwave a burrito so hot that he himself could not eat it?"
Also - if you're omniscient and you already know your future, does that imply that you do not have free will?
As to free will, well that's something only Catholics and Orthodox hold onto. I don't believe Muslims or many Protestants (Calvin?) adhere to that.
That of course raises the question why even attempt logical proofs, but here we are.
Not really:
* https://edwardfeser.blogspot.com/2010/02/dawkins-on-omnipote...
Yeah:
> And that is why modern readers typically do not understand the argument. For example, they often think it is an attempt to “define God into existence,” as if Anselm believed that arbitrarily attaching certain meanings to certain words could tell us something about objective reality. But this is to confuse what Scholastics call a nominal definition – an explanation of the meaning of a word – with what they call a real definition – an explanation of the nature or essence of the objective reality a word refers to. Anselm is ultimately concerned with the latter, not the former. While he no doubt thinks that any reflective language user will agree that the notion of “that than which nothing greater can be conceived” is implicit in his use of the word “God,” the more important point he is driving at is that being that than which nothing greater can be conceived must as a matter of objective fact be of the essence or nature of being divine, just as (to use a stock modern example) being a compound of hydrogen and oxygen is of the essence of water.
* https://edwardfeser.blogspot.com/2010/11/anselms-ontological...
Which also has the stronger critique of the argument:
> The lesson is not that Anselm’s argument is unsound so much as that it presupposes knowledge (i.e. of God’s essence) that we cannot have. Moreover, the idea that reason points us to the existence of that than which there can be nothing greater is something Aquinas himself endorses as long as it is developed in an a posteriori fashion, as it is in Aquinas’s Fourth Way.
* Ibid
For a better argument, and summary of that argument, see Aristotle:
* https://tofspot.blogspot.com/2014/07/first-way-some-backgrou...
* https://tofspot.blogspot.com/2014/08/first-way-moving-tale.h...
* https://tofspot.blogspot.com/2014/09/first-way-part-ii-two-l...
* https://tofspot.blogspot.com/2014/10/first-way-part-iii-big-...
* https://tofspot.blogspot.com/2014/11/first-way-part-iv-casca...
* First 30m of this podcast: https://www.youtube.com/watch?v=SfQldsGrMfk
Book which covers arguments from Aristotle, Plotinus, Augustine, Aquinas, Leibniz:
* https://www.goodreads.com/book/show/35592365-five-proofs-of-...