On your comment on omniscience, I think the best response to it is simply that the being knows that it's not a brain in the vat, or some such thing. I can't say how the theoretical omniscient being knows that because I'm not omniscient: but it's logical that it could just simply know it. A better paradox would probably be whether an omniscient being knows how it feels to not know something.
I’ve heard that latter claim but I’ve never bought it. Let’s take an extremely simple monist view that our mental states are just an emergent phenomena of our brain states, that is to say our minds arise out of our physical brains the way “wetness” does out of physical H2O molecules. If this was the case an omniscient being could examine those brain states and, because it knows every detail about what mental states they entail, know exactly what it would be like to not know something without actually personally being in this position.
As for an omniscient being “just knowing” that it is omniscient because, as you implied it is omniscient (while you aren’t), this is completely circular. Implicit in your reasoning seems to be the assumption that omniscient beings truly are possible but that’s the very thing in question so can’t be assumed in order to argue such a being “could just simply know” it was omniscient.
If you accept my premise that you could, in principle, create a video game character that knew everything about the world it inhabited and believes it has always existed but simply can’t know, due to the limitations of being a mind, whether or not it was in the only universe or being totally deceived I don’t see how declaring a being “just knows” helps. Surely such a video game character could believe it “just knows” whether or not it was in such a realm but surely that character would be wrong. The same goes for the sub-god idea professed in noelplum99’s video. Surely a sub-god who knows everything about the universe it inhabits could believe it knew everything and surely it would be wrong. If their is no substantive way these scenarios are different from the proposed position of an omniscient being then we have no reason to believe omniscience is possible.
Our imaginations could be lacking, perhaps there is a substantive difference between the scenarios we are proposing (though in this case I highly doubt it), but saying a being “just knows” doesn’t help remove the problem. Saying a being “just knows” isn’t even an argument, but rather a bald assertion. By this reasoning you could dismiss any and all criticism about logical contradictions directed at a proposed god like this by declaring, by definition, that it really can exist. Take your own example above: By the “just knows” reasoning you could have argued that an omniscient being would “just know” what it was to not know something because the ability to know what it feels like to not know something is included in the definition of omniscience (at which point we’re back to the follies of ontological arguments). After all we aren’t omniscient how can we say what an omniscient being does and doesn’t know.
I hope you can see the problem here. An apparent logical impossibility like this can’t be swept away without argument by declaring our knowledge imperfect and that some other being could “just know” everything.
Thanks for the comment though.