Is existence greater (or not) than non-existence?
That’s a matter of debate, but it’s really irrelevant. Even if it’s given that actual existence is greater than merely imagined existence, there’s nothing that necessitates something imagined being actual, even if it would be greater if it were actual.
Basically it boils down to this: you can tell me to imagine the greatest, most perfect thing in the universe, and then say it would only be the greatest if it was actually existing, and I can say “yep, but just because I imagined ‘the greatest thing’ doesn’t mean it must exist”. You’ve shown that something is greater if it exists, as opposed to being merely imagined, but you haven’t proven that it
must really exist.
This is why my ice-cream example is pertinent; I’ll admit that an ice-cream cone that exists is better than one that’s imagined, but there’s nothing necessitating the ice-cream cone being real.
Here’s another flaw in the argument: something that actually exists is greater than something that is merely imagined, and I’m imagining this object as having the property of necessary existence, but this is an
imagined property, not an actual one. Since actual existence is greater than imagined, the most I can do is
imagine certain traits, and since those traits aren’t
actual they can’t be used to necessitate any actual existence. My entire mental conception remains in a lower order, and no imagined property can cause this conception to cross the boundary into actuality, just as actuality can only come from actuality (which, incidentally, is a sound proof for the existence of God, since only God can be eternally actual, and things exist but aren’t eternally actual, therefore things are brought into actuality by the only eternally actual thing, which is God; the universe exists, therefore there is a God).
So, in short, the argument shoots itself in the foot by supposing that actual existence is greater than imagined existence, because that automatically means that anything I imagine need not be actual.
Peace and God bless!