The irony of the body is that it retains desire even after it loses its desirability. Soul and body decouple. (Maybe they were never coupled). But it's possible that there are moments in our lives when we feel both desirable and feel desire–and in those moments we maybe get a sense of what it is to be immortal. Most people's notion of immortality is just the permanent extension of their sexual prime (endless erotic consumption). Certainly this seems to be what anti-aging research or transhumanism ultimately reduces to.
Sometimes I think what it would take to get me to give up writing. I really have no concept of myself outside of this activity. I really don't think I'd want to live without the possibility of serious writing–not because life isn't worth living without literary activity, but, because I've overdeveloped this one faculty so much—committed so much hope to what it might yield—that the rest of me has atrophied. For instance, sometimes I sense that lovers are disappointed in me emotionally—find me closed off, hard to reach, or simply uninteresting. I think, well, yeah, because I'm saving the best parts for something else.
One thing I noticed reading the letters and diaries of my favorite writers is that they read for help, practical help. Great writers often really resemble groups of scientists trying to solve a problem. Even though we think of works of art as individual, works of literature as individual. Often there's a set of social and spiritual problems that beset an entire age. The best writers are all approaching the problem (the human, the human condition) one way or another. The only difference between art and science is that, in art, there's no solving anything. Hypothesis gives way to hypothesis, never fully becoming theory (philosophical theories are just insecure, masquerading hypotheses).