> It’s observing passively.
This is a byproduct of the process. You cannot observe passively if you still have a very strong imprint of a doer. When you start observing the tingles and the sensations, you still observe them from the center and there's a distance from the center and the sensations. The only way this center disappears is if the regions of the brain that create imprints lower their activity.
I'd say it is very easy to accomplish it when you're sleepy (especially after you wake up during the night and go back to sleep). There's no need to shut anything down through high focus, brain does it naturally to paralyze the body and lose the waking state.
"My Stroke of Insight" by Jill Bolte Taylor goes through many side-effects experienced by the meditators, but through a lens of a brain stroke.
> Thought ceases because it interferes with being aware, not because you are experiencing brain death.
Not sure about that. The verbal/visual thinking can be a strong feedback loop to the underlying unconscious processes. The only way I can see that it stops is if it is suppressed to unconscious, you've learned to not have it in focus.
Also, many people have no visual and verbal thoughts. They don't have an imprint of standard modes of thinking at all. I'd say the definition of thought needs to expand to sensing. Any sensation is a thought. Focus on verbal/visual thoughts is misplaced.
I do agree that people learn to eventually do this without the side effects of practice. They can probably transition to a different brain activity without dealing with the breath ever again.
I think a much better standard for meditators is to ask them if they feel like their whole body is alien, or if they have something like alien hand syndrome. Losing thoughts, yet still being the body (or even the space around the body) is just another form of thoughts.
The imprint of a doer gives you the feeling of someone controlling the body or doing the thinking. For example, I can get lost in thoughts so hard that I no longer have imprints of controlling the body. Somehow I leave the shower and dress myself yet I know I don't remember doing any of it.
To also move the conclusion further, it sounds like the ultimate goal is to feel like you're not separate but that you're whole, so in that case it must be that this body, from that perspective, is fully without individual imprint, behaving completely like an input/output machine, no inner subjective experience present.