Does consciousness exist in sleep

[jjjjj]

The common opinion on sleep is that it's unconsciousness but I did some research and read that you can dream in all 5 stages, and when you don't dream you ruminate, also that you do some "conscious" actions such as movement, sleepwalking, talking in sleep, etc.

Does that mean that a level of consciousness still exists?

Like you don't remember everything during sleep but if you did remember everything would it be more of a memory of being extremely drowsy or complete unconsciousness (like in anaesthesia)?

Or would it simply be a memory of being there (like when you wake up from anaesthesia it feels like you just opened your eyes after closing them but after sleep it's never like that)?

[Dekan]

Dream conciousness, from my own somnolent experience, exists in at least two forms or types:

 

1. The "weak" form. This is when you dream of (say) falling off a cliff. As you're about to hit the ground and be killed, you think "No, I won't really die, thank Heavens, - this is just a dream."

 

2. The "strong" form - This is when you realise that it's just a dream, and you think "Hmn, I can take control of the way this dream's going, and there won't be any repercussions when I wake up. So I can perform all kinds of discreditable actions, and get away with it."

 

These type-2 "lucid dreams" are great fun, but alas they don't seem to occur very often.

[Marat]

One way to approach the question is to note that when you wake up after having been asleep, you are aware of time having passed. Thus you did not just drop out of existence while asleep, so that there was no dimly aware recording of the sensation of time passing, but rather, the awareness of that semi-conscious recording of time having passed when you awake shows that you were at least minimally conscious while sleeping. If this were not true, you couldn't tell on awakening whether you had just been unconscious for an instant and collapsed, or have slept for 9 hours.

[jjjjj]

Also does "dreamless sleep" even exist? We know that...

We can dream in all 5 stages of sleep (not just REM)

We move around very often throughout the night (all in nREM since you're paralyzed in REM)

Memories are sorted out constantly in all stages of sleep.

Also this http://www.goertzel.org/dynapsyc/2005/ZhangDreams.htm

And if you look at history of sleep "research"

First we thought that you dream once or twice every night and most of it is dreamless because we didn't remember dreams

Then that we dream throughout REM.

Then that most dreams are in REM and some in nREM.

I think that it's reasonable to say that you dream constantly and there is no "dreamless sleep"

Or if there is, it's almost certainly not a thoughtless void like most people imagine, and the thoughts in it are very similar to dream thoughts (perhaps not connected in a dream...?)

[John Cuthber]

If you were not, at some level, conscious when asleep, you would fall out of be a lot more often.