(CNN) A physician who had been diagnosed with cancer once told me that, before he became sick, patients would periodically ask him, "Doc, will you pray for me?"

"I'd 'pooh-pooh' the idea," the physician told me. "Then, I became sick, and realized how important spirituality was in patients' lives."

I heard such stories again and again as I was interviewing physicians for a book, " When Doctors Become Patients ." Doctors facing the prospect of their own death would tell me how they finally began to truly understand the vital roles played by spirituality and religion in many patients' lives.

I was reminded of these conversations when I read the news of a 14-year-old girl who had died of cancer, but who had asked that her body be cryopreserved after her death in the hope that one day she might be cured.

I can only begin to imagine what the girl -- known only as "JS" to protect her privacy -- and her parents must have felt. Her parents were divorced, and while her mother supported her wish to be frozen, her father had opposed it. The cost of the procedure in this case, according to the judge, is about $45,000. The case went to court, and the judge ruled in JS's favor.

The girl's wish to continue to live is, of course, not surprising. After all, death is arguably the greatest tragedy of life, and something that most of us try at all costs to avoid. And the death of a child is generally even more disturbing than that of an adult -- all living things eventually die, but it feels like a child has been cheated of a full life. So I am sure that the thought that JS might one day come back to life greatly comforted her and her mother.

Sadly, cryopreservation of bodies has never been shown to work. No one has ever been frozen and then come back to life when thawed. Of course, proponents argue that eventually medical science will indeed figure out how to make it work. And the lack of success so far has not stopped some 250 people from being cryonically preserved in the United States, according to one study

But even if cryopreservation could work, in say 100, 200 or 300 years, it would raise a number of important issues and questions. For a start, everyone the frozen person knows will long since be gone. The world will be a very different place. Climate change may have destroyed many of the world's major cities. Where would the thawed people live? How would they support themselves?

These questions might seem self-evident, and nix any interest in cryonics. Yet the idea -- and, to some, the appeal -- of the process persists. Why?

For a start, stories of the dead coming back to life or achieving immortality fill our religions and myths -- from Jesus to Orpheus (who descended to the underworld to bring back his deceased beloved), Sir Galahad and Frankenstein. When I attended medical school, the gates of a nearby cemetery proclaimed words from Corinthians, "The Dead Will Be Raised."

Psychological research suggests that we all seek means of symbolic immortality -- a sense that we can somehow transcend the mortal confines of our lives -- through religion (a sense of the afterlife), our children, our creative work, or "experiential transcendence" ("drugs and sex and rock 'n' roll"). In my reform Jewish Sunday school, I was taught that when we die, "We still live on Earth in the good deeds we have done, and in the hearts of those who cherished us."

In short, many of us have difficulty grasping the apparent finality of death. Critics argue that as a society, we engage in widespread denial of death -- overly focusing on youthfulness, and discriminating against the elderly.

Similarly, after many people's hearts or brains have failed, we often keep these individuals alive on machines, at great costs. Indeed, one study suggested that "one out of every four Medicare dollars, more than $125 billion, is spent on services for the 5% of beneficiaries in their last year of life."

Most individuals, if asked hypothetically, would likely prefer to have that money used in other ways -- for their own or their children's or grandchildren's education, for example. Yet many people still work to delay their own death, or that of loved ones, for as long as they can.

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Ultimately, none of us knows what happens when we die. I am sure that the thought of coming back to life gave JS immense solace. If so, I am glad. But as adults, we should, I would argue, try to find better ways to accept more fully the finality of death here on Earth, whether symbolically or through other means.

Seneca, the ancient Roman writer, said we should live each day of our lives as if it may be the last -- because it indeed may be. And that might be the biggest lesson of these stories that we hear about cryogenics and expanding use of end-of-life machines -- that it is not so much about the science, but about living life to the fullest while we are here. That's something we should all work on together.