From A High Yogic Experience Achieved With Mescaline. Mescaline is a hallucinogenic substance found within Peyote cacti with purported effects similar to LSD and psilocybin.

Suddenly there dawned full awareness of three great truths which I had long accepted intellectually but never, until that moment, experienced as being fully self evident.

and

1. There was awareness of undifferentiated unity, embracing the perfect identity of subject and object, of singleness and plurality, of the One and the Many. Thus I foundmyself (if indeed the words “I” and “myself” have any meaning in such a context) at once the audience, the actors and the play! Logically the One can give birth to the Many and the Many can merge into the One or be fundamentally but not apparently identical with it; they cannot be in all respects one and many simultaneously. But now logic was transcended. I beheld (and myself was) a whirling mass of brilliant colors and forms which, being several colors and several forms, were different from one another-and yet altogether the same at the very moment of being different! I doubt if the statement can be made to seem meaningful at the ordinary level of consciousness. No wonder the mystics of all faiths teach that understanding comes only when logic and intellect are transcended! In any case, this truth, even if at an ordinary level of consciousness it cannot be understood, can, in a higher state of consciousness, be directly experienced as self evident. Logic also boggles at trying to explain how I could at once perceive and yet be those colors and those forms, how the seer, the seeing and the seen, the feeler, the feeling, and the felt could all be one; but, to me, all this was so clearly self-evident as to suggest the words “childishly simple!”

2. Simultaneously, there was awareness of unutterable bliss, coupled with the conviction that this was the only real and eternal state of being, all others (including our entire experience in the day-to-day world) being no more than passing dreams. This bliss, I am convinced, awaits all beings when the last vestiges of their selfhood have been destroyed- or, as in this case, temporarily discarded. It was so intense as to make it seem likely that body and mind would be burnt up in a flash. (Yet, though the state of bliss continued for what I later knew to be three or four hours, I emerged from it unscathed.)

3. At the same time came awareness of all that is implied by the Buddhist doctrine of “dharmas,” namely, that all things, whether objects of mental or of sensory perception, are alike devoid of own-being, mere transitory combinations of an infinite number of impulses. This was fully apparent as are the individual bricks to someone staring at an unplastered wall. I actually experienced their momentary rising of each impulse and the thrill of culmination with which it immediately ceased to be.

Buddhist scholar John Blofeld in the Psychedelic Review, 1966. Full article here.