Panati's Extraordinary Endings of Practically Everything and Everybody, a book whose accuracy I have sometimes found wanting, has an interesting take on a familiar fact. According to Panati, sex and death are two aspects of the same phenomenon. Organisms that reproduce asexually do not have finite lifespans like we do. The amoeba simply splits into two amoebas, which in turn exist until themselves splitting. As long as it isn't killed, it multiplies endlessly without ever dying.
But in sexual reproduction, two individuals contribute genetic material that grows into a new organism, then they die. Death is simply the logical corollary to a process that uses a mere fraction of an organism to produce a new creature. In humans, it may happen decades after the sex act itself, but it's inevitable--and linked to the fact that we are sexual beings.
"In one sense," writes Panati, "we possess immortality, but not where we want it. We have it in our generational genes. We'd prefer it in our body, in the form we cherish, in the face that gazes reassuringly back from the mirror" (p. 6).
Despite Panati's argument, there isn't much to envy about amoebas. They don't care about their immortality any more than your sex cells care about theirs. Lacking consciousness, they are unable to care.
For your part, cloning wouldn't satisfy your desire to live forever. You would think of the clone as a new person, just as you think of identical twins as two separate individuals despite their genetic sameness. What you really want is a continuance of your soul, not your body. Even if you don't believe in the soul, you recognize a distinct inner self which perishes at death. Immortality, to you, means the permanent existence of this self.
Previously, I raised the question of whether you'd be willing to die if a clone with all your memories were created in your place. That sort of experiment could be the key to immortality, assuming that merely copying the information in your brain to another vessel would effectively move your consciousness there, like a transfer of data between computers.
There are problems with that assumption, however. In his book How to Write Science Fiction and Fantasy, Orson Scott Card discusses a fictional species that communicates by transferring memories. According to Card, "individual identity would be much less important to them than to us. And death would be almost meaningless. As long as you passed memories before you died, then everything you thought and experienced would continue to live on, so that even though you might cease to take part, everyone in the community would clearly remember having done everything you did!" (p. 50)
Card here implies that there is some intangible "you" existing independently of your memories, so that even if those memories are passed to someone else before your bodily death occurs, "you" perish. But if "you" are nothing more than your memories, as some philosophers have argued, then how is a memory transfer from one body to another any different than what happens in life from each moment to the next?
I believe it is different. No matter what the philosophers say, there is something intangible inside us. Consider the attempt to create an android with human emotions. You might program it to have a distinct state called "sadness," where it would display symptoms such as frowning, downcast eyes, and broken concentration. But it's doubtful that any of this would cause the machine to experience sadness, any more than an actor experiences the emotions he performs.
Inner experience, one of the most mysterious features of human life, is not just information in the brain. It is the part of yourself which experiences the information. You can't prove it exists. You're directly aware of your own, but you can only infer that other people are something more than machines programmed to behave as though they have inner experience.
Philosophical materialists typically attempt to ignore or downplay the mystery of inner experience, viewing it as merely another illusion to be swept away by the inevitable march of scientific progress. The problem with that argument is that since all illusions are perceived through a person's inner experience, to call inner experience itself illusory borders on the tautological. Inner experience is the elephant in the room, the one thing in existence that absolutely defeats a materialistic explanation.