I strongly urge others to repeat the experiment, which with pure gas is short an harmless enough. The effects will of course vary with the individual, just as they vary in the same individual from time to time; but it is probable that in the former case, as in the latter, a generic resemblance will obtain. With me, as with every other person of whom I have heard, the keynote of the experience is the tremendously exciting sense of an intence metaphysical illumination. Truth lies open to the view in depth beneath depth of almost blinding evidence. The mind sees all the logical relations of being with an apparent subtlety and instantaneity to which its normal consciousness offers no parallel; only as sobriety returns, the feeling of insight fades, and one is left staring vacantly at a few disjointed words and phrases, as one stares at the cadaverous-looking snow peak from which the sunset glow has just fled, or at the black cinder left by an extinguished brand.He was half-joking, but half not.The punchline is the "fade" at the end, and the joke's on us metaphysical seekers.
Well, looks like Oliver Sacks is carrying on in a similar vein: no nitrous or Hegel in his case, but it's fundamentally the same quest for transcendence through pharmacology. And, it seems about as likely to succeed.