I have identified a possible flaw in a thought-experiment-based argument I posted here ('Kirk dies') some time ago. I wrote:
"We willingly go to sleep at night. We willingly get anesthetized for an operation. We might also be happy to go into 'cold storage' for a long space journey or to survive a devastating catastrophe on earth (a 'nuclear winter', for example).
But, what if, though we could be certain the hibernation device would not fail to keep our body alive and in a resuscitatable state, we just did not know whether or not it would ever get around to waking us up?
Going into such a device becomes exactly equivalent to a game of Russian roulette. Death (as in the death of the body) is functionally equivalent to not waking up, ever. All the death of the body does is make it impossible ever to wake up. It takes away hope.
But, from the point of view of the unconscious person, hope – or any kind of expectation – is irrelevant. So the experience of death is equivalent to the experience of going into a state of unconsciousness – nothing more."
The problem (as I now see it) is that I was overlooking the fact that a body which is revivable must, like any living thing, be in some sense sentient.*
A person requires consciousness as well as a social context, etc., and so is much more than a sentient body or body components. But the latter is the basis and sine qua non of the former and – crucially – is what makes me me and not you.**
The higher functions of my brain (or my 'mind') fade in and out, and may go permanently before my body fails. Once they are gone, I (as a functioning person) am gone. But in another sense I live on in my separateness until the death of the body.
In a fundamental sense, basic sentience is a far more interesting phenomenon than consciousness or self-consciousness, as it is the root of the latter. If there is a deep mystery in the universe, sentience is it. The primitive organism in a rock pool attracted to the warmth of the sun: this is what is most remarkable.
A human body, then, in some imagined technology-induced kind of super-hibernation would be unconscious but sentient (probably in many ways). And such a 'sleep' – even if extended indefinitely – is not at all equivalent to death.
I thought I had demonstrated (assuming that a functioning human body is entirely physical, i.e. soulless) that there can be no afterlife, no waking up (as it were) after death.*** But my little thought experiment was, I think, fatally flawed.
All sorts of possibilities – especially in an infinite universe (or multiverse) with multiple copies and so on – remain in place (faint though these possibilities may be).
* I am assuming here that any process which completely shuts down the functioning of organs, cells etc. would not be reversible: it would in effect kill the body.
** I know there are difficult questions about what it is exactly that confers identity on an individual or what identity consists of or in which I'm skirting here, but (if one rejects a Cartesian view) the living body is clearly basic.
*** Looking at things from a first-person perspective helps to keep these sorts of discussions grounded. Look, for example, at the sort of question that a dying person might ask him/herself. Something like: "Is this the end, the end of all experience (for me)?" I put the 'for me' in brackets because the burden of the question lies elsewhere. The dying person is not interested in me-ness but in whether or not there are going to be any more experiences. One can imagine – looking forward – waking up as oneself at another (say, earlier) stage of life, as someone else entirely or even as a giant cockroach – and I think these imaginings are at least coherent. (Kafka's giant bug had psychological continuity with the man who suffered the transformation. My cockroach doesn't (necessarily), and nor does my someone else. Thus the inserted clause, 'looking forward'.)