I've put up a rough draft of a new chapter for Why Buddha Touched The Earth. Here's an excerpt:
For believers in the paranormal, all these coincidences and visions and unexplained events are evidence of some sort of supernatural entities or powers. To the skeptical, they are the operation of random chance given meaning by the overeager pattern-recognition circuits of the brain, or illusions or delusions or hallucinations, malfunctions of the sensory nervous system.
From a Zen Pagan perspective, neither of these explanations is satisfactory. The true believer's approach makes claims about the objective universe that don't hold up to controlled experiment and observation. The skeptic's neurological reductionism neglects the fact that most events in the universe occur outside of laboratory controls, and ignores the person to whom the experience is happening. The subjective dimension is flattened out.
When we practice ritual, or engage in meditation, or seek otherwise to alter our consciousness, we expect to see and experience strange and unusual things. To encounter "spirits" or to have some other sort of transpersonal experience after staying up all night dancing or drumming around a bonfire, or fasting for days, or sitting unmoving in mediation for hours at a time, or ingesting strange herbs, or working yourself into a ritual frenzy, is not odd. To the practitioner, these experience are the goal of the work.
Dismissing the experience as "mere delusion" is like calling a performance of Bach fugue a "mere disturbance of air". It is technically correct, and even captures important information - understanding that disturbance of air allows for the proper acoustic design of concert halls, after all. But it misses the aesthetic dimension that makes the whole thing worthwhile.
In the same way, calling a shaman's vision a "hallucination" may be accurate, even useful in certain contexts. (If someone was going to risk their life or well-being on information that came to them in a vision, for example, it would be good to point out that such information is not a reliable guide to objective reality.) But it misses the mystical element, the deep emotional content, of the experience.