[LogicWings]

What it is, it seems, is the product of a mind that refuses to accept that actualized concepts exist outside of present human understanding.

Following your statement to its logical conclusion, then how do YOU know they exist? Are you something more than human? By definition they are outside 'human understanding' therefore you can't understand them either, or even know of their existence, except as a supposition.

If we are going there then, everything we can't explain is due to Unicorns. And you can't prove otherwise.

[unspun]

I would make a distinction between understanding fully (comprehension) and understanding in part (potentially up to and including a "working knowledge"). If what lies beyond our comprehension may be understood in part due to inference, or to the volitional efforts of someone there presenting us knowledge of its nature and substance (Bible happens to call that "glory," literally translated "weight" from Hebrew) then we may know in part (even if "through a glass, darkly").