Hallucinogenics can produce all of the sorts of visions mentioned on this thread and even much more extreme. A decent dose of LSD, mushrooms or DMT have made many question whether consensus reality is actually real. DMT trip reports are fascinating reading. There's many ways visions can come about. Fast for a week and 'beings' will start to appear. During a difficult prolonged childbirth, lights and angels can appear (for some).
Experienced meditators all say the same thing - the visions are both real and unreal at the same time. Visions occur in the mind only, but then so does consensus reality occur only in the mind. That's the revelation.
