OK, now this question may dip into psychology a bit much, but I'd like to look at this phenomenologically.
How would we explain something that "shows up" to one as a hallucination, and is quite real to him or to her, but does not, and cannot "show up" to others?
I could say: "I see the minotaur playing chess with himself in the corner." But the minotaur does not "show up" to anyone else. No one else has any consciousness of the minotaur. How is it that we can intend something that is essentially not there, while the minotaur seems like a genuine experience to the hallucinator?
Could this hallucination have some kind of transcendent qualities, and if so, what is the reason it is not to be "experienced" by all?
What is everybody's take on this idea?
[Lightly edited to enhance readability -TT]