Recently, a non-TM friend asked me, "In the TM movement, what was secret, aside from the mantras?" That question really got me thinking. I have come to the conclusion that there were at least six types of secrets in the TM movement: (1) things that were secret to the lower levels, but were revealed to upper levels, (2) things that were not secret in the earlier days of the TM movement, but later were made officially secret, (3) things we were explicitly told to keep secret, and to tell the public that these things were secret, (4) things we weren't explicitly told to keep secret, but we picked up the cues that we should keep them secret, and (5) things that we were explicitly told to lie about to the public in order to keep them secret, (6) things that Mahesh kept secret from all of us (or you may term that "lied to us about") that we only found out through the internet, etc.
Type (1) might be the religious/Hindu/Vedic side of the movement. Or the fact that Maharishi instituted celibacy for some factions of the movement.
Type (2) might be the fact that the mantras were sounds to attract the favor of Hindu gods. Another example is that "God Consciousness" was later re-termed "Glorified Cosmic Consciousness." Also, originally it was strictly forbidden for non-"flyers" to see "yogic flying." Later the public was invited to watch.
Type (3) might be the mantras, how they were were chosen, and how to do TM, the TM-Sidhis, and other TM programs.
Type (4) might be to not translate the puja if someone asked us. Or to not tell anyone that learning how to choose the mantras took 5 minutes.
Type (5). I remember Maharishi telling us to "tell the audience at the introductory lecture that the puja is a 3-minute ceremony." Someone asked Maharishi in dismay, "It takes me 10 minutes! Am I doing something wrong?" Maharishi replied, "It will feel like 3 minutes to the student." Or Maharishi's explicit instruction to "tell the students that the puja is a non-religious ceremony, just for the purpose of giving gratitude to the tradition of masters." However, on my TM Teacher Training Course, Maharishi told us that the real purpose of the puja was to temporarily lift the TM teacher into a higher state of consciousness, and sped his/her growth towards enlightenment.
Type (6) might be the fact that Maharishi's "timeless wisdom, the purity of the teaching" consisted of him teaching different mantras and different criterion for choosing mantras on different TM Teacher Training courses. Or that Maharishi was not Guru Dev's favored disciple, but rather his clerk. Or that TM research is biased, that some people have harmful results from doing TM, and that other techniques have proven as good as TM.
Please, add your memories of TM secrets to this list!