In case my mind is preserved I can't imagine existing forever in this supernatural realm, however nice and pleasant it may be there but if my mind is manipulated or even ereased then we're no longer speaking about me anymore so whatever happens to this supernatural medium - call it soul or whatever you want - happens to somebody else.
Of course I don't mind living longer than the ~80-90 years and I'd really enjoy seeing loved ones that died before me but I don't believe that this or similar scenarios will happen. It's not that I don't want an afterlife to be true but it's rather that I don't see any compelling evidence that conscious existence is possible without a brain. So whether "I" existed in some obscure unconscious state before my conception or whether I didn't exist at all before this moment is of no importance to me because I can't tell the difference.
BMCDA, you say you do not wish to be eternal.
Well, it's just as I stated above: if I'm still myself I don't want to exist forever but if I'm turned into a different "person" I couldn't care less since that's no longer me.
Perhaps you could stop for an hour and be completely still, don’t think, but just listen and see if you can “sense” being outside of your body.
It's interesting you mention this experience since I've read a lot about this kind of experiences although I've never had them myself. However, have you ever considered the possibility that these experiences are not of supernatural origin but are generated by parts of your brain?
I mean our brain is a complex organ and much is still unknown but I don't think we have to invoke supernatural explanations when dealing with such phenomena. How we perceive reality is dependant on how the different parts or our brain function and interact with each other (see split brain, temporal lobe epilepsy. In the meantime it is well known that meditation, prayers or similar practices can induce the experiences you described above (I think it's already possible to induce these experiences externally; maybe I try it out since "sensing" of being outside of my body sounds quite interesting ;^).
Especially since WW1 the effects that injuries of different parts of the brain can cause in a person have been studied and so far the possibility that our mind and the so-called spiritual experiences we may have are simply natural phenomena hasn't become less probable. Of course this doesn't disprove the existence of a supernatural realm but it also doesn't suggest that our brain is in some way connected to this realm.
Regards
So what is this 'being'? Is it a supernatural medium that enters the natural world at our conception (or is generated at our conception) to get recorded and then to leave the natural world to enter the supernatural realm again and exist there for ever?
Yes.
If this is the case then what happens to my mind that got presumably recorded on this supernatural medium when it leaves the natural world? Is it preserved at the transition or is it heavily altered or maybe even ereased?
It is preserved, but you also gain exponentially greater awareness and knowledge.
It's not that I don't want an afterlife to be true but it's rather that I don't see any compelling evidence that conscious existence is possible without a brain.
This is the bottom line. For those who believe that consciousness is but a physical phenomenon, there is a tendency to also believe there is no afterlife and there is also a tendency to believe that consciousness can be achieved through artificial intelligence.
Well, it's just as I stated above: if I'm still myself I don't want to exist forever but if I'm turned into a different "person" I couldn't care less since that's no longer me.
But what if you are everything you are here and much, much more?
However, have you ever considered the possibility that these experiences [getting “into” the spirit] are not of supernatural origin but are generated by parts of your brain?
I have considered it, but on personal experience I know what it is. There is no way I could ever convince you, it is virtually impossible to express in words. But if you give it a try, perhaps you will experience it as well.
I think it's already possible to induce these experiences externally; maybe I try it out since "sensing" of being outside of my body sounds quite interesting.
I do hope you give it a try! If you are able to sense your being outside your body, then you may even entertain my conclusion, i.e. that the physical brain is a transmitter/receiver for the spirit.
How might you explain something that I've experienced, BMCDA?:
On time, in silent prayer, I had the distinct impression that I was holding a sword in my hand. It had some specific significance to me. As I remained in prayer, an intercessor came by, looked toward me, and immediately his eyes got big and he smiled in some astonishment and said something like, "Wow, look at that sword!"