>>This is central to my original question. Does a mystical or spiritual experience happen in the external world when our perception of it is enhanced or is it an illusion produced by chemicals in the brain?<<
I don't know the answer to that Peter, I don't think anyone does. I don't know where to start to find a definitive answer.
For myself, I'd <i>like</i> it to be external. If it's option B, then my first thoughts are it's tantamount to a form of self-delusion or something like a mental illness when only the ill person feels the experience is real so it's tying my brain in knots trying to see how any form of reality can be perceived. Is what we think of as reality only a construct of the illusion produced by chemicals in the brain?
That's the end of my cerebral yoga practise for this evening, I'm off to watch Lost, it's easier to understand ;-)