Quote Originally Posted by D.O. View Post
Dark retreat is practiced in Vajrayana. It is also practiced by Mantak Chia.

By all accounts, one experiences "visions".

Based on your knowledge, what do you suppose happens when someone secludes themselves in pitch black darkness for several weeks?

Are these visions merely clairvoyance or is it more profound than that?
here's my 2c:
Q. What is the difference between a "trip" or a "hallucination" and a "vision?" What makes each one 'real?' for most people, veracity comes from verification - if some one else can verify it, then it must be at least 66% real, right? most people always have at least 1/3 doubt.

once we realize that we can't rely on others to establish our opinions, thoughts or worldview, we realize we have to trust (or test) our senses of perception...which eventually reveals that some things can only be sensed mentally. also (and more relevant to your question) the senses must be functioning properly.

let us consider some examples of improper sense function:
go to walmart, winco or any chain supermarket and shop around, or just hang out. pay attention to how spiritually aware you are before, during and after the trip. the combination of over-labeling the products, the bright lights, the bright floor, the noisy people, the music, the noise generating toys, and more, etc. will completely overwhelm the senses for several hours or longer. first, the stores will overwhelm and exhaust your sense-organs, then second they will overtake your mind. This is apparent afterwards when for nor good reason, people start talking in marketing slogan- speak with phrases like "gotta have it!" and "just do it." and "have it your way" and "i'm lovin' it" etc.

one more example:
got to a concert. how long does the music stick in your head? probably for days or longer.

to summarize:
most people have never experienced proper functioning of their mind or sense organs (including the brain). After the first few hours of 'recovery' from normal life, the sense organs recover and the mind calms down, and that's when monks on retreat start to see things - usually their own deeper thoughts bubbling up and usually not spiritual visions - although i admit it can be either.

in order to perform their higher spiritual functions, the aspects of the body must not be doing any physical functions. period.

my 2c