If "we realize that mystical experiences originate from the same neurological mechanisms that underlie hallucinations ... I bet dollar to donut that the reality experienced by meditating Buddhists and praying nuns is entirely contained in their mind and is not a glimpse of a 'higher' realm, as tantalizing as that idea may be," he concluded.
Exactly right, and I tend to discount most mystical experiences as dreamlike fantasy.

Of course, my experience of Kirk's words right now is just a recreation within my neurological circuits, as is the experience of the sweet tea I am drinking (I think I am drinking) right now. Who is to say for sure which sweet taste is real? What is to tell me that there is a 'Kirk' behind those words (no offense, Kirk)?

And we are left with the mystery of just how every twist and turn of physics, chemistry, earth development, biology and evolution twisted and turned just right to allow a brain so wired as to let me savor Kirk's words, plus all the rest that went into evolving a 'me' and a 'Kirk' ...

In other words, it is a 'Koan' because there are mysteries. 'Great Doubt' because we cannot say for sure. All we have are our suspicions, this seeming miracle of being alive in a universe to ponder it all, and this life ... just like this cup of tea ... that seems to sit before us. I think.

Agnostic Gassho, Jundo