Allen Stairs offers a spirited reply, and an amusing last line, but I am a bit more sympathetic with your worry. You might check out the Stanford Encyclopedia of Philosophy entry on beliefs about the afterlife which I co-authored with William Hasker. There is a terrific book on hell by Jerry Walls called Hell: The Logic of Damnation and a good reference work published by Oxford University Press, A Handbook on Eschatology. Jonathan Kvanvig also has a good book on hell that carefully runs through the possible justifications for belief in hell. Minor point: for many religious traditions in which there is a hell, hell is understood to be self-created rather than created by God. This is colorfully and vividly represented in Milton's Paradise Lost. Philosophical arguments for belief in an afterlife (or life beyond life) are often developed in the context of the case for and against theism, though philosophers who are atheists have believed in an afterlife (e.g. Buddhist philosophers). The British idealist McTaggert made an interesting case for an afterlife without theism --his viewpoint has been described as Heaven without God. Ronald Dworkin in his book Religion without God also has some interesting speculation about how secular humanism can (in principle) accommodate an afterlife.
In both the legal and the familiar sense of the word "murderer," the answer is no. You certainly wouldn't be charged with murder in a case like this, and if you were, successfully arguing that you didn't actually kill the person but merely allowed them to die would lead to a "not guilty" verdict. Murder, as it's usually understood, is unlawful killing or, in the non-legal sense, morally unjustified killing.
That said, someone might argue that if you're in a position to save someone's life and you don't, then you're guilty of something just as bad as murder. No doubt we can come up with hypothetical cases where this might be so. For instance: Alex intends to kill Bob; he's got the means and the will. But on his way to do the deed, he discovers Bob unconscious and bleeding by the side of the road. Suppose it's clear that Alex could save him; calling 911 and staunching his wound until help arrives would do. But Alex does nothing except wait for Bob to breathe his last. In this case, we might say that Alex has really just taken advantage of a twist of fate to accomplish what he would have done by himself anyway. We might well think: Alex is as morally guilty as he would be if he'd shot Bob to death. But whatever we say about this case, it's hard to draw general conclusions from it. In general, both the law and common-sense morality distinguish between intentionally harming (or killing) someone and simply not helping them and the fact that there are some cases where the distinction seems untenable doesn't show that it's untenable in general. After all, there might be many explanations for the fact that someone doesn't act to save someone else: shock or fear or confusion, for example. None of those add up to malice, let alone murder.
Just to give you something more to chew on: suppose you could save Rob and could also save Bob, but no way could you save both. You flip a coin and save Rob, letting Bob die. You were capable of saving Bob, but you didn't, but pretty clearly this doesn't make you a murderer. It doesn't even mean that you did anything even slightly wrong. Not the case you had in mind, but a clear example of letting die that's not the moral equivalent of murder.
I think you are right, and Freud says that we can never really think of ourselves as completely dead in the sense that there is nothing of us left. I suppose the good thing about the losing life idiom is that it leaves open the possibility that there is more to us than just this body, and perhaps a soul or something similar continues to exist, or has that possibility. In fact, your comments remind me of those philosophers like Epicurus who argued that death is not to be rationally feared since after it occurs there is nothing to experience the absence of life.
Lots of interesting questions here, and I won't try to do all the issues justice. But a handful of quick thoughts.
First, philosophy doesn't usually have a perspective on a question because the questions philosophy deals with tend to be inherently controversial. Philosophers have views, but there's almost always disagreement amongst philosophers on almost all philosophical topics. This one is no exception. That said if you were to take a poll these days, I'm pretty confident that at least among philosophers in the "analytic" tradition (very roughly: influenced by formal logic, science, careful attention to language and meaning...), you'd find that most don't think there can be consciousness without a body to embody it. This is largely because the more we learn about the workings of the mind, the more we see that it's intimately connected with the functioning of the brain.
Turning briefly to one of your examples: suppose a bit of information were taped to the top of a tall object in an operating room. And suppose it turns out that a patient who reports a near-death experience is able to give a detailed account of the information, even though from the operating table there was no "ordinary" way to see it. What would this show?
It's not at all clear. In particular, it's not clear that it would do much to support the idea that the mind is separate from the body. What we'd have is someone whose brain is functioning now and never actually died. Somehow, this person has some information that we wouldn't expect him to have. But what best explains how he came to have the information is hard to say - even if he reports an experience of floating above the operating table. Saying that the mind separated from the body and travelled up through the room to examine the information doesn't help much. How would that work? Does the bodiless mind have eyes? How did the interaction between whatever was up there on top of that tall object and the disembodied mind work? How did the information get stored? How did the mind reconnect with the patient's brain?
The point isn't that the mind must be embodied. The point is that a case like this would only amount to good evidence for minds separate from bodies if that idea gave us a good explanation for the case. As it stands, it's not clear that it gives us much of an explanation at all, let the best one.
I'm not quite ready to go along with my colleague's answer, but my answer isn't any more hopeful.
If time has the structure of the real line (as we usually think) then even if it's infinite, every moment is only a finite time away from now. (Compare: every real number is only a finite distance from 0.)
But even if time is infinite in the way the real number line is, it doesn't follow that there will be a duplicate of you somewhere off in the future. To get that conclusion woud take a lot of extra and optional premises. More important, even if there will be a duplicate of you someday, there's no good reason to think it would be you, nor is there any good reason to think that you could look forward to its experiences. (These two aren't quite the same issue, as it turns out.)
Clearly there's a lot in the background here. If you're interested in more reading on the core problem, i.e., the problem personal identity, you might have a look at Martin and Barresi's anthology, called Personal Identity.
It's a lovely question. Let me start by recommending a couple of things to read. One is Bernard Williams' classic paper "The Makropoulos Case: Reflections on the Tedium of Immortality" (in his book Moral Luck.) Another is Larry Temkin's paper "Is Living Longer Living Better?" (in Journal of Applied Philosophy, 2008.) One of the interesting things about Temkin's paper is that he believes the question isn't merely idle. He believes there is at least a serious chance that we might learn to halt the aging process.
Be that as it may, let me raise one issue among the various possible ones.
It may seem that living forever would be an unmitigated good. But Williams argues forcefully that this isn't so. His argument has two parts, but I want to note just one of them: if we lived more or less as we find ourselves now, then eventually life would become unutterably boring. The title of his essay is taken from a play in which a woman (Elena Makropoulos) has been given a potion that lets her live indefinitely. Life eventually becomes so tedious that suicide is her only escape.
Is Williams right? Would unending life be insufferable? I don't know. Not everyone finds Williams's case convincing. Temkin, among others, offers some reservations, but Temkin concedes that there may be much more to what Williams has to say than might seem to be so at first.
This suggests that simply granting everyone unending life might be granting them something that they would come to hate. If so, then waving the magic wand, so to speak, might be doing great harm.
Of course what I just said seems premised on giving immortality to people whether they ask for it or not. We could mitigate the problem at least somewhat by imaging that only those who consent get the "gift." That helps, but it leaves a residual issue: since we have so little idea what would really be entailed by living indefinitely long, is there any hope that anyone could make an informed decision? And if not, would it be right to make the offer? There's a good chance that many people would find it too superficially attractive to resist. But if Williams is right, they would have been better off resisting. Is the moral risk too great here? I, for one, don't feel that I have a good answer.
There's far more that could be said here than these few comments cover. But it's a really interesting question; what I've tried to suggest is that the answer isn't as obvious as many people might think.
There's clearly an enormous amount that could be said about this, but here are a few thoughts.
Suppose that some person is suffering, and to avoid certain complications, suppose that there's no "cure" for their pain. Now suppose that the person actually wants us to take his life. (Imagine that he isn't in a position to do it himself.) Then it's not just obvious that it is wrong, all things considered, to kill him. That's why there's a serious debate about euthanasia.
That said, there are important differences between typical human beings and most other animals: humans don't just have immediate desires and aversions; humans have self-concepts which include plans, desires and values that bear on their own futures. Most animals, or so we believe, don't have any such things. We normally think that people's views about their own futures count -- that it's wrong simply to ignore them. In particular, if someone is suffering but doesn't want to die, we think that carries tremendous weight. Most animals, or so we think, don't have the capacity for the relevant thoughts. They don't have a conception of themselves as being who have potential futures about which they have plans, wishes and desires.
That's at best a contingent fact, and it may not be true of all animals. If a creature has a conception of its own future and has desires about the course of that future, then that makes a moral difference -- or so we normally think. And so it may well be that even in the case of some non-human animals, killing a creature in order to end its suffering is wrong.
None of this is meant to address all the issues that your question raises. Other panelists may well have things to say on matters that I haven't even raised. But the normal human capacity to be able to think about one's future is surely relevant to sorting all this out.