What are some good checkmate arguments against religion?

[MindForgedManacle]

The argument is indeed presuppositional, as it presupposes God's existence in order to define necessary existence as a characteristic of God in the opening premises.

It defines what is meant by "God", it does not start by saying God exists and then appends attributes to him.

It relies on an equivocation between subjunctive possibility and epistemic possibility.

That would only be the case if a user of the argument claims it conclusively establishes God's existence.

Plantinga's argument has indeed been challenged, and has all the shortcomings of other historical ontological arguments which have been categorically challenged and shown to be invalid.

http://en.m.wikipedia.org/wiki/Ontological_argument

Not sure what I'm supposed to respond to here, seeing as you just dropped a link. And since I seem to have to repeat myself: I do not, nor have ever stated, that Plantinga's argument actually works.

The introduction of "necessary existing being" is problematic. If something exists necessarily, is existence a property of something existing contingently?

No, but the word salad was a nice move to cover up the incoherence.
All necessary existence is referring to is existing in all possible worlds, i.e being metaphysically necessary in the same way that "2+2=4" is metaphysically necessary.

If I replace the necessarily existing God with Necessary Unicorn, is the argument still valid as proof of any supernatural entity?

I'd like to see your argument for a necessarily existent unicorn that both validly postulates a unicorn as necessarily existent and still retains all the attributes that a unicorn is supposed to have.

It's because you're the douchebag who sits in the front row of Philosophy 101 classes, presenting "new original thoughts of your own" covered in the first few chapters of course material you didn't bother to read.

Tell me just ONE place I've claimed to have "new and original thpughts of my own". You tried lying about this shit in that other thread on the topic of the necessity of God, and I see you keep doing it.

This is because you continue to repeat like a broken record that ontological arguments are logically valid, without even bothering to glance at the historical objections posted in the same Wiki pages you're copying the arguments from.

I've seen them, and pretty much EVERY single one questions the SOUNDNESS of the arguments, not their validity.

If you'd bother to look in to the objections to the arguments instead of claiming "no one disputes them" and "they're logically valid," this wouldn't be an issue.

Okay, I've called you on this before. I have not said that "no one disputes these arguments", as I clearly dispute them, seeing as I'm an atheist. I said they're logically valid, which has been confirmed to the point that they pass automated theorem provers routinely (Gödel's ontological argument was recently prooved (in the sense of validity) recently, in fact).

Instead you dismiss objections and continue to introduce largely debunked arguments as "logically valid."

You've got to be trolling me. As in the last thread on this (which you conveniently abandoned after I showed you were batshit wrong by quoting a post of mine debunking Plantinga's argument), I have not dismissed objections to these arguments, aside from one's which stupidly claim they're logically invalid despite passing automated theorem provers and staying consistent with their logical system's axioms.