Hi @mgaft1! Happy to answer to question, at least I try to : If the astral body and the 'I' would completely leave the physical body you would 'dead'. There's still a 'connection', that's why 'partially'. It's like a shifiting of positions, not a departure, you change the state of consciousness, from waking to sleeping. The 'I' is more or less split so to say, a part of it stays in the physical body. You can't measure it in numbers. Thoughts and cognitive processes are only possible when fine nerve-structures are being destroyed. The daily recognition would not be possible without this process of destruction during waking up and going to sleep. That's just how your 'brain' works, and your body as well. The power which is used to create your consciosuness is used to build and repair these damaged structures during your sleep and you can't perceive it. The regeneration / development = unconsicousness, because the power is needed to build and recover. The destruction / degradation = consciousness, the powers do the damage. That's why lack of sleep can be dangerous because your body can't recover as it should. If your consciousness would be still in your body, if you would still be conscious, you wouldn't sleep, you would be awake and therefore there would be more destruction. So you have to leave your body (the 'I' and the astral body) to enable the recovery. I hope that helped :) Thank you very much for your question and interest.