I know a similar question has been adressed before but I feel it did not address my question. When we sleep all our pain/ache on our body vanishes for some time span, you do not know what happened around you for that time span, it seems like you travelled 8 hours forward in time. Many of motor neurons stop firing. Now imagine if we sleep dreamlessly in such a way that you can't be waken up by any means, but are still alive, can that be considered as death (in your perspective)? In sleep you have a waking point but if there is none like in death won't infinite dreamless sleep be death for you? What am I expected to see in a dreamless infinite sleep if I don't feel death? It's a proven fact that you know that you are dead when you are dead.
There seems to be some misunderstandings that need to be cleared up.
First, when we sleep, all our pain/ache does not vanish completely. It is still there; we just don’t experience it fully as when we are awake. If it’s mild, we may be oblivious of it during sleep. But if it’s strong enough, it’ll disturb our sleep, cause us to toss and turn, and even wake us up from time to time during the night. Or when we’re sleeping peacefully and someone pokes us sharply on our body, we will wake up from the pain. This proves that the pain that occurs in our body during sleep does not vanish and can be felt by us even we’re asleep.
Next, it’s true that many motor neurons stop firing during sleep, but many are still firing too, especially those that maintain respiration, muscle tones, and occasional movement during sleep. Many motor reflexes, which need firing of motor neurons, are still functioning as well. You can prove this by touching a cornea or stroking a sole of a sleeping person.
Third. But the most remarkable difference between sleep (including dreamless sleep) and death regarding the brain is that all neurons is the sleeping brain are alive, metabolizing, and firing from time to time, even if there is no alert consciousness or dreaming in it. On the contrary, no (or minimal) neurons in the dead (or almost dead) brain are alive, metabolizing, and firing – behaviorally, this results in no respiration, no motor movement and tone, and no motor reflexes – whatsoever. And if you do the electroencphalography (EEG) on the sleeping brain, you’ll see a lot of lively changing waves all the time in the sleeping persons (even with no dreams) but flat lines in the person with dead brain.
Q: Now imagine if we sleep dreamlessly in such a way that you can't be waken up by any means (but still alive) can that be considered as death (in your perspective)? In sleep you have a waking point but if there is none like in death won't infinite dreamless sleep be death for you?
A: No to both questions, as discussed above, there’re a lot of differences between the dreamless sleeping brain and the dead brain, both behaviorally and electrophysiologically. Even outwardly, in my perspective, the dreamless sleeping person breaths peacefully, moves a little bit sometimes, and do not rot, but the dead person does not breath, does not move even a bit, and rots.
Q: What am I expected to see in a dreamless infinite sleep if I don't feel death?
A: You will see similar things that you see when you’re sleeping in dreamless sleep (sleep stage I to IV) – that is, you’ll see nothing – you just sleep.
Q: Its a proven fact that you know that you are dead when you are dead.
A: I don’ think this is a proven fact; I haven’t seen any proof of this. Simple logic tells that when you are dead, you don’t know anything anymore, and you don’t know anything means you don’t know that you are dead, too.
Purves D. Unit V. Chapter 27 Sleep and Wakefulness. In: Purves D, Augustine GJ, David Fitzpatrick D, Hall WC, Lamantia AS, McNamara JO, Williams SM, editors. Neuroscience 3rd ed. Sunderland, Massachusetts: Sinauer Associates Inc; 2004.
Schwartz JRL, Roth T. Neurophysiology of sleep and wakefulness: Basic science and clinical implications. Curr Neuropharmacol. 2008 Dec; 6(4): 367–378. doi: 10.2174/157015908787386050.
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You state 'proven fact', without references or citations.
"To sleep, perchance to dream—ay, there's the rub, for in that sleep of death what dreams may come when we have shuffled off this mortal coil, must give us pause" - Shakespeare
Sleep is categorically not just 'jumping forward in time'. Consider the mysteries of general anaesthesia where it's widely reported time is not sensed as having passed, vs time estimation ability during sleep which seems to be linked to slow wave sleep.
It's not just dreaming, which differentiates sleep from death. Dreams are however integral to sleep, it must be noted people dream on average 4 times a night, and two weeks with sleep but where dreaming is prevented results in hallucinations and risk of death, as discussed in my answer on this question: Have any thinkers applied empiricism to the dreaming and deep sleep states? So memory of and reporting of dreams is not a good guide to whether they have happened.
Integrated Information Theory attempts to distinguish between waking, sleep, and other types of unconsciousness. It is however a field with far more questions than answers, because the mysteries of sleep and dreaming are bound up with the mystery of consciousness, the deepest question in both philosophy and science.
Who feels death, or, infinite dreamless sleep? What you are, is not an abstract essence separate to your embodiment. In what way is sleeping-you, you? In Buddhist thinking we do not remain the same person, we wake each day anew, and even to each moment, as our thoughts arise and fade.
"What we are today comes from our thoughts of yesterday, and our present thoughts build our life of tomorrow" - Dhammapada
If we awake from death, how much are we the same person? Buddhist thought says causes and conditions are reborn, not any transcendent or unchanging soul. The inability to be present, requires other times for our lines of thought or action to culminate, or reach fruition. Being fully present however, we awake to now, and set our thoughts and actions on that basis.