What, specifically, is lost at the moment of death? Certainly not consciousness, transient brain state—or more precisely: Brain state is destroyed not only when we die, but in fact constantly. Twain writes “I do not fear death. I had been dead for billions and billions of years before I was born, and had not suffered the slightest inconvenience from it;” better yet, that “I” (the experiencer of qualia) has died—been irretrievably obliterated—thousands of times in the last minute without noticing. So we shouldn’t be concerned with the cessation of conscious experience.
It seems the only self worth worrying about is fully described in structure of the brain (or perhaps in even more general symbols), without regard to its dynamic state. What becomes inaccessible only after the heart stops? Memories, prejudices, opinions, reflexes, half-recollected scraps of poetry and unfinished plans: information at a higher level of abstraction. Clinical death destroys that self simply because memory becomes a locked box when it ceases to move the hands and lips.
This will not always be the case. Even at present, small pieces of the self-as-aggregation-of-abstractions can be documented and stored—incompletely, imperfectly—eventually reconstituted on the substrate of another three-pound mass of fatty brain tissue (just as the aggregation of abstractions I identify as myself includes as substructure borrowings from Auden and my kindergarten teacher). Human beings are far less interesting than we think if Ray Kurzweil can reconstruct an emotionally-satisfying father from genes and old photo albums; nevertheless it doesn’t strike me as outrageous to suggest that any being so reconstructed deserves to be called part of Kurzweil’s father.
At some level it’s just a question of where we’re comfortable drawing the line that separates the self from the rest of the world. Let holism be damned—then the kind of immortality conferred by creating paper records of memory, even of trips to the grocery store, is not poetic but real in the most literal sense possible.