Alan L. Smith, who was a medical scientist at that time, described his spontaneous mystical experience when he was 38 year old. This excerpt was taken from an online article "Cosmic Consciousness Experience and Psychedelic Experiences: A First Person Comparison " by Allan L. Smith and Charles T. Tart

My Cosmic Consciousness event occurred unexpectedly while I was alone one evening and was watching a particularly beautiful sunset. I was sitting in an easy chair placed next to floor-to-ceiling windows that faced northwest. The sun was above the horizon and was partially veiled by scattered clouds, so that it was not uncomfortably bright. I had not used any marijuana for about a week previously. On the previous evening I probably had wine with dinner; I do not remember the quantity, but two glasses would have been typical. Thus, we would not have expected any residual drug effects.

The Cosmic Consciousness experience began with some mild tingling in the perineal area, the region between the genitals and anus. The feeling was unusual, but was neither particularly pleasant nor unpleasant. After the initial few minutes, I either ceased to notice the tingling or did not remember it. I then noticed that the level of light in the room as well as that of the sky outside seemed to be increasing slowly. The light seemed to be coming from everywhere, not only from the waning sun. In fact, the sun itself did not give off a strong glare. The light gave the air a bright thickened quality that slightly obscured perception rather than sharpened it. It soon became extremely bright, but the light was not in the least unpleasant.

Pascal's Mystic Amulette 

The year of grace 1654, 23 November, day of St. Clement, Pope and Martyr. From about half-past ten in the evening until about half-past twelve, midnight, FIRE. God of Abraham, God of Isaac, God of Jacob, not of the philosophers nor of the Wise. Assurance, joy, assurance, feeling, joy, peace. GOD OF JESUS CHRIST, my God and thy God. Thy God shall be my God.

Forgotten of the world and of all except GOD. He is only found in the ways taught ill the Gospel, THE SUBLIMITY OF THE HUMAN SOUL. Just Father the world has not known thee but I have known thee, Joy, joy, joy, tears of joy. I do not separate myself from thee, They left me behind, me a fountain of living water. My God do not leave me. Let me not be separated from thee eternally. This is eternal life that they should know thee the only true God and him whom thou hast sent. JESUS CHRIST-JESUS CHRIST. I have separated myself from him; I have fled, renounced, crucified him. Let me not be forever separated from him. One is saved only by the teaching of the Gospel. RECONCILIATION TOTAL AND SWEET. Total submission to JESUS CHRIST and to my DIRECTOR. Continual joy for the days of my life on earth. I shall not forget what you have taught me. Amen.

Finally it was the hundredth day. Soen-sa was outside chanting and hitting the moktak. All at once his body disappeared, and he was in infinite space. From far away he could hear the moktak beating, and the sound of his own voice. He remained in this state for some time. When he returned to his body, he understood. The rocks, the river, everything he could see, everything he could hear, all this was his true self. All things are exactly as they are. The truth is just like this.

Soen-sa slept very well that night. When he woke up the next morning, he saw a man walking up the mountain, then some crows flying out of a tree. He wrote the following poem:

 That night another reality opened its door, another dimension became available. Suddenly it was there, the other reality, the separate reality, the really real, or whatsoever you want to call it -- call it god, call it truth, call it dhamma, call it tao, or whatsoever you will. It was nameless. But it was there -- so opaque, so transparent, and yet so solid one could have touched it. It was almost suffocating me in that room. It was too much and I was not yet capable of absorbing it.

A deep urge arose in me to rush out of the room, to go under the sky -- it was suffocating me. It was too much! It will kill me! If I had remained a few moments more, it would have suffocated me -- it looked like that.

I rushed out of the room, came out in the street. A great urge was there just to be under the sky with the stars, with the trees, with the earth... to be with nature. And immediately as I came out, the feeling of being suffocated disappeared. It was too small a place for such a big phenomenon. Even the sky is a small place for that big phenomenon. It is bigger than the sky. Even the sky is not the limit for it. But then I felt more at ease...

The next morning when I heard the bird, everything dropped away and the next thing I knew I was the bird.
I was the listening.
I was everything.
Everything and Nothing.
So ordinary.

I saw that the real "I" of me was only beingness, was only existence, and that my beingness was exactly the beingness of the universe. And when I saw that, I identified with every being in this universe; I identified with every atom in it. And when you do that you lose all sense of being a separate individual, an ego.

When I saw that, that I AM the Amness of this universe, I then saw the whole world as just an image in my imagination, like a dream.

I imaged or dreamt that I was a body. And I'm dreaming right now that I'm this body.

One night not long after my twenty-ninth birthday, I woke up in the early hours with a feeling of absolute dread. I had woken up with such a feeling many times before, but this time it was more intense than it had ever been. The silence of the night, the vague outlines of the furniture in the dark room, the distant noise of a passing train – everything felt so alien, so hostile, and so utterly meaningless that it created in me a deep loathing of the world. The most loathsome thing of all, however, was my own existence. What was the point in continuing to live with this burden of misery? Why carry on with this continuous struggle? I could feel that a deep longing for annihilation, for nonexistence, was now becoming much stronger than the instinctive desire to continue to live.

‘I cannot live with myself any longer.’ This was the thought that kept repeating itself in my mind. Then suddenly I became aware of what a peculiar thought it was. ‘Am I one or two? If I cannot live with myself, there must be two of me: the ‘I’ and the ‘self’ that ‘I’ cannot live with.’ ‘Maybe,’ I thought, ‘only one of them is real.’