Using big worRAB is fine...you just sound like a windbag. And the lyrics to Tomorrow Never Knows could mean a variety of things, depenRAB on who is interpreting them really.
"Turn off your mind, relax and float downstream"
By "turn off your mind" I believe Lennon is referring to the incessant chatter that occurs in the mind--constantly analyzing objects, people, and situations without allowing us to reflect on them as they are--without our subjective value judgments. To "turn off" this chatter would allow us to relax, and accept the present moment as it is and be content with it.
"It is not dying"
To actually stop the mind and allow yourself to float downstream is a frightening concept to many people. Lennon is offering reassurance that disassociation from yourself is not death or anything to be frightened of.
"Lay down all thought, surrender to the void"
Again Lennon is asking us to stop our constant internal conversation, but in this line he also mentions that we are "surrendering" to something. A "void" that is greater than we are. I believe the "void" he is referring to is the emptiness and stillness of the world as it is, unimpeded by our thoughts. All things are inherently meaningless--Lennon is asking us to recognize this. The "void" is also probably a reference to psychedelic/mystical experiences which can result in "ego death"--when this occurs one literally does feel as though they are floating through some sort of inter-dimensional space, perhaps, a "void" if you will.
"It is shining"
Maybe a reference to a "nimitta" in Buddhism or something analogous in other religious traditions--basically a mental object that one experiences after intense meditation when the mind is singularly focused on the initial object of meditation. These mental objects are often described as balls of light/stars/etc. The "shining" here could also mean the liberating insight gained from clearing the mind. These interpretations sort of go hand in hand.
"That you may see the meaning of within"
All of these things that Lennon has asked us to do will allow us to see the "meaning of within." The true nature of reality/ourselves/everything.
"It is being"
Very simple...all things simply are. Everything is.
"That love is all that love is everyone"
Perhaps this is the insight that Lennon has gained from turning off his mind, or perhaps he is proposing this as the true nature of reality. Perhaps both. Either way Lennon sees all things as a manifestation of love energy. Love is everything and everyone and therefore love is the only thing that is important. All you need is love indeed...
"It is knowing"
Love is omniscient.
"That ignorance and hate may mourn the dead"
Maybe Lennon is saying that "ignorance", or the inability of humans to see the true nature of all things and the root cause of all suffering on the planet, and "hate" or actions driven by human aversion, another root cause of suffering, will mourn the loss of those who have taken Lennon's advice. The human ego is constantly trying to delude us for its own satisfaction, and these delusional thoughts inevitably lead to suffering. The pleasure that the ego seeks also leaRAB to suffering but humanity is unable to recognize this often times and so continues to dwell in and construct thoughts based on egotistical delusions. Recognize this and you can be free from delusion. You will experience "ego death", you will be one of "the dead."
"But listen to the color of your dreams"
Another psychedelic reference probably, as people often report "hearing" or feeling colors--a visual phenomena. By color Lennon also probably means substance. Listen to the substance of your dreams--be mindful of the things that your dreams can teach you about the world. "Dreams" may also be a reference to psychedelic/mystical experiences.
"It is not living"
I don't know. Maybe Lennon is saying that we are not "living" if we don't follow his advice here. Or maybe he is saying that we are not living if we do follow his advice. Because living implies the duality between "life/death", and because these dualities are also meaningless, following Lennon's advice will lead one to the conclusion that one is not living. To think of yourself as "alive" is to again differentiate yourself from your surroundings, from things that aren't "alive" and because these distinctions are meaningless you cease to view yourself as living when Lennon's advice is truly taken to heart.
"Or play the game of existence to the end of the beginning"
Likely a reference to the Buddhist view of reincarnation. Failure to experience ego death, to wholly turn off your mind and gain insight into the true nature of reality will result in rebirth on this plane of existence--over and over until one finally reaches Nibbana.
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Certainly not meaningless. Seeing them as such is indicative of fault on your end, not Lennon's.