[bojan]

Originally Posted by CraigS

To the best of my knowledge, they still don't know why anaesthesia has the effect you describe. And the reason is: that no-one has really worked out what consciousness (or sentience) is. Anaesthesia reverses whatever it is.

You don' have to know what consciousness is to know why anaesthesia has its effects. The way I see it is simple: it blocks the acquisition of data from outside world (by stopping the CPU clock (or whatever this is in brains) and there is no more memory storage during that time.
Obviously, what the computer might "perceive" (after restarting the clock) is instant change of environment, but the sense of time passage will not be there (because for it, there was no passage of time - because nothing was recorded during the time clock was inactive.

I know, I am stressing the analogy with computers ad nauseaum.. But computers are the simple but common enough information systems we use in everyday life, and I think it is a good analogy for start.

Originally Posted by CraigS

"Acceptable" would suggest you have your own criteria.
What if you already exist somewhere else, but you just don't know it, (nor ever will) ?
.. or, what if you are the copy, and the original thinks the same about you ?

Well, I have to start with something... but I am not saying the criteria is not going to be changed...
About copies of "me"..
If a copy can exist without me being aware of it, that means it is not "ME", this is someone else then..
And this is definitely true because the experience of that copy from the moment of its "creation" is different from mine.. and it may even not be aware of "me" (In theory I may be watching while it was created from the other room through the one-way mirror). It IS different person (or, different information system - because the content of memory is already different).

Originally Posted by CraigS

My point is that trying to force a conclusion to an 'open-ender' in science, limits one's thinking and invariably prematurely closes off other options which might be real. (Eg: my favourite .. exo-life … trying to force a 'yes' or 'no' is unproductive and can lead away from reality).

On the contrary, in this discussion I actually I tried to use the method "Reductio ad absurdum".
In other words, I am trying to see if I will hit the contradiction at the end, which will/may point into other direction.
So, actually, my mind is open (I think)

Or perhaps I just have read too many SF novels