The concept of transmission goes back to a story of how Gautama Buddha was sitting in silence before giving a dharma (i.e., a how-to) talk. Korean Zen Master Seung Sahn [see the Kwan Um site] related it as follows:
"Holding up a flower on Vulture's Peak." Again, Buddha had appeared for a dharma speech in front of a huge gathering. For several minutes he was silent. Finally, he picked up a flower. Everyone was confused except Mahakashyapa, who smiled. Then Buddha said, "My true dharma I transmit to you."
The Four Pillars of Zen, typically attributed to Bodhidharma, the Indian who spread the teaching of sudden illumination to China about 1,000 years later, emphasized the idea of a "special transmission":
1. A special transmission outside of the scriptures.
2. No dependence upon words or letters.
3. Direct pointing at the soul of man.
4. Seeing into one's own nature and the attainment of Buddhahood.
The implications are that 1) the way (dharma) to become what Gautama, Jesus, et al. became is through seeing into one's own nature; 2) this can be assisted by another who has seen into his own nature; and 3) it's not done by transmitting conceptual understanding.
Current thinking, even among people with a conceptual understanding of advaita or non-duality, is to dismiss the possibility of transmission with a response such as: "... If, as the Buddha said, there is nothing to do or achieve
... what is there to be transmitted?" Or, more condescendingly: "If all is One Mind, where's the mind that's transmitting and the one that's receiving?" These attitudes, I believe, have shut out the true mystery of how the "individual" becomes aware of his true nature as That which is not divided.
In Alfred Pulyan's correspondence with Richard Rose, his first mention of the technique was as follows:
I have got something all that man can get on this earth most probably and my job & your job is to transfer it from me to you. O.K. Here is Alfred Robert Pulyan guinea-pig. How are we to extract it from him? It is otherwise called "the transmission."
Other references in Pulyan's correspondence include these:
Words do not "transmit" it, but negatively they can show the way.
"What do you want to define as friendship?" It is the state previously illustrated in detail. It is the "transmission" of Zen. It is when each is "open" with the other. It is an approach of the One Self in each. It is a way to realization. It demands a certain discrimination & a certain culture. A trigger-happy "hood," a sadist, a chawbacon, a "fishwife," an autocratic boss, a proud intellectual, the Pope, --- all these can easily have a "mystic experience" or "cosmic consciousness" (even though they might call it "only subjective"), but not so easily the "awakening" experience which Jesus said is denied to them and reserved for simple people.
However, the attention one gets, needs to be far more individualized & personal because this is not "learning," it is partly a transmission through friendship or love.
My mind "contains" yours actually....
The last statement may have been the one that triggered Richard Rose's intuitive pick-up of the technique, which he later described in The Psychology of the Observer, giving the type of mental activity that occurs on the part of the teacher and the student.
Rose said that transmission could be forced on a student, but if the student wasn't on the brink of a realization by retreating from untruth to the point of near-realization then he or she wouldn't know whether the realization was real or artificial. Unfortunately, none of his students reached that point while he was still active. The closest occurrence was with the wife of a student, who wasn't happy about her husband's interests. When she walked into a room where her husband and a few other students were sitting in silence with Rose, she immediately got "hit" by the presence in the room. She fell to her hands and knees, weeping, and remained thus for nearly an hour. She attained what Rose called the "mountain experience," where she realized that her husband didn't exist and that all of humanity was an illusion. But that was as far as she could go. She didn't realize her own individual non-existence. So Rose brought her out of it.