Hallucinations - Oliver Sacks

These four first-hand accounts stood out for me:
 
William James (The Varieties of Religious Experience), describing his own transcendent experiences with nitrous oxide:
“Our normal waking consciousness, rational consciousness, as we call it, is but one special type of consciousness, whilst all about it, parted from it by the flimsiest of screens, there lie potential forms of consciousness entirely different…. Looking back on my own experiences, they all converge towards a kind of insight to which I cannot help ascribing some mystical significance. They keynote of it is invariably a reconciliation. It is as if the opposites of the world, whose contradictoriness and conflict make all our difficulties and troubles were melted into unity…. To me [this sense] only comes in the artificial mystic sense of mind.”
 
Daniel Breslaw, a student volunteer on psylocibin:
“The heavens above me, a night sky spangled with eyes of flame, dissolve into the most overpowering array of colors I have ever seen or imagined; many of the colours are entirely new – areas of the spectrum which I have seem to have hitherto overlooked.
…. Every five eons or so a nurse arrives (in the aspect of a cougar, a differential equation, or a clock radio) and takes my blood pressure.
…. Here is a fire extinguisher in a glass case, evidently an exhibit of some sort. A bit of staring reveals that the beast is alive: it coils its rubber hose around its prey and sucks flesh through the nozzle. The beast and I exchange glares, then the nurse drags me away. I wave goodbye.
A smudge on the wall is an object of limitless fascination, multiplying in size complexity, color. But more than that on sees every relationship it has to the rest of the universe; it possesses, therefore, an endless variety of meanings, and one proceeds to entertain every possible thought  that there is to think about it.”
 
Eric S., ecstatic on LSD, was told by a voice that humans are “love and light”.
 
Dostoevsky talking to two friends about his epilepsy:
“You all, healthy people, he said, can’t imagine the happiness we epileptics feel during the second or so before our fit… I don’t know if this felicity lasts for seconds, hours or months, but believe me, for all the joys that life may bring, I would not exchange this one.” Prince Myshkin in The Idiot: “His spirit and his heart were illuminated by an immense sense of light; all his emotions, all his doubts, all his anxiety calmed together to be changed into a sovereign serenity made up of lighted joy, harmony and hope; and then his reason was raised up to the understanding of the final cause.”
 
Anyone who has had such an experience has no need to have its significance explained. Anyone who has not might wish to take note.