Suppose you look into the mirror and out of the blue, while you expact to see a well-known face, you see nothing. Would that not be frightening? The notion ‘i exist’, ‘i am’ depends on such confirmation, i have seen. For long we see a body and subconsciously this confirms ‘i exist’ and also vice versa. Maybe one is not aware of this proces of confirmation but still it is there.
The same with vedana, sanna, sankhara and vinnana. It is like a proces of mirroring. If suddenly vedana or other khandha’s would cease, the notion ‘I exist’ is challenged, because for long there is this inner scheme: "There are vedana’s, thoughts, perceptions (etc) so ‘I exist’ and vice versa.
Our sense of “I am” circles around the khandha’s as it were. It relies on them. It is build upand based upon them. If this notion of ‘I exist’, ‘I am’ is challenged that can be scary.
Our internal scheme is…there are tactile sensations, there are feelings, emotions, thoughts, perceptions, so, “i exist”. And also “I exist” because there are bodily sensations, emotions, thoughts etc. This relies on eachother.
Internally happens exactly the same compared to looking into a physical mirror, see the face you see all the time, and be confirmed “I exist”. Maybe some think this is theory, no. There is really a long standing identification with body and mind and a notion of" I am" that very much depends on a constant subconscious proces of comfirmation. The root of all fear, i think.
Identity gives us a feeling of safety, but at the same time that grasping becomes a cause for not letting go, not seeing the empty nature of mind and it does not really provide safety.
The sutta’s teach: vinnana is not me, mine, my self. Ofcourse this also becomes very apparant when we loose eye-vinnana, smell-vinnana, ear-vinnana, taste-vinnana, tactile vinnana. It is not that we cease to exist when we become blind, deaf, without smell and taste ability, or without any tactile sensation, right?
But what happens when we loose mind-vinnana, mental vinnana? What happens when there are no mental objects (dhamma) at all to discern? If at that moment we black out, suppose we do, then it prooves, i believe, we are mental vinnana, and buddha’s teachings proof to be wrong.
The sutta’s also use this reasoning that when, for example, a certain feeling disappears, we do not experience that we disappear, right? This reasoning establishes some kind of logical trust, faith, certainty that we cannot be that feeling. If i am thoughts, then i must disappear when thoughts cease, right, but such does not experientally proof to happen. If we would black out or loose all experienttial notion that we are present at the moment vinnana ceases, suppose, then it proofs Buddha’s teachings are wrong, because then it proofs ‘vinnana is me, and my self’.
Blacking out can also not be the nature of meditation, samadhi, wisdom, awakening, seeing, direct knowledge, i believe. And that is the aim of Dhamma. Most likely, i think, blacking out means that one has just become unconscious and is fully absorbed in bhavanga state. I would not associate this with cessation, because cessation is taught as a Truth that is seen, subtle. If one is unconscious there is no seeing nor direct knowledge.
There are also many buddhist meditation masters who do not speak of blacking out in meditation. In deep meditation one comes to see the true nature of mind, that what is very subtle, hard to see, the uninclined (Ud8.2) and does not black out. I also do not know sutta’s that describe blacking out as part of meditation or samadhi practice. I believe it is only an idea that cessation of khandha’s is blacking out. Blacking out is just becoming unconscious, i believe, like deep sleep, narcosis, not death but just unconscious.
Many meditation masters teach that meditation can bring us to a point we really see that we are not the khandha’s. Praising blacking out seems odd for a Dhamma that teaches that the end of defilements is for one who sees.