It was only to be expected that with advances in medical science we are tending to live a bit longer. But a longer life is not necessarily a better one. Medical science can give cancer sufferers a year or two extra, but it has failed to do much about arthritis. And, as Bryan Appleyard points out, the longer we take to die, the longer the young are forced to stay young. “In Britain,” he tells us, “there are now 6.8m kippers.” Meaning, kids in parents’ pockets eroding retirement savings. But there are deeper issues yet.

The last century saw western philosophers of religion deconstructing the idea of body-soul dualism, or what the philosopher Gilbert Ryle famously called “the ghost in the machine”. Dualism maintains that who and what you are is an immaterial substance, a soul, dwelling within the material body. For religionists, dualism provides a rationale for personal immortality. When our bodies die our immaterial souls continue to live, floating off into paradise, purgatory or hell. The status of this disembodied conscious self has never been viewed by theologians as satisfactory. Hence the importance of the doctrine of the soul’s reunion with a brand new body after the Second Coming, or what many American evangelicals call the Rapture. The significance of the death of dualism, which appears to have entered popular culture with remarkably little fuss, is, to put it brutally, that when you’re dead — that’s it folks — you’re dead.

Yet as if to demonstrate the tenacity of immortal longings, despite even the optimism of some about a future resurrection, the decline of the spooky-stuff soul has coincided with an explosion of interest and research into life extension, longevity — dare one say it, a decided reluctance to go finally into that dark night, or even temporarily before that Last Day meet with one’s Maker. Appleyard, starting from the premise that an extended life is now feasible, has written an enthralling essay on the contemporary meaning of dying and death. It is also a book about the meaning of life. As he writes, citing Octavio Paz: “Tell me how you die, and I will tell you how you live.” Appleyard chronicles with admirable and often dazzling accessibility two strands of science that underpin life extension. The more respectable the science, the more modest the life extension (decades rather than centuries), but the closer to immortality, the more whacko the science.

For Appleyard, however, it is the new culture of mortal denial that is culturally significant. Is it the inevitability of death that gives life and love their savour? Or is it human, as the Spanish philosopher Miguel de Unamuno insisted, to insist on our immortality? And would immortality make us happy or find us longing for death from sheer boredom? Appleyard orchestrates an impressive range of genres (history, technology, personal reminiscence, anecdote, anthropology, philosophy) to establish his developing argument about what it means to live and to die in the 21st century. At one extreme he unpacks the rigorous research of the British biologist Professor Tom Kirkwood, who has specialised for three decades in the ageing process of genes and cells.

Kirkwood has challenged the notion that we are programmed to die. Instead, we are programmed to age, which is what brings on death. According to him, though, the ageing process could be genetically stabilised if not reversed; hence his qualified optimism about life extension. At the other extreme, we are introduced to the bizarre figure of Aubrey de Grey, a Cambridge autodidact who promotes a nano-tech engineering solution to curing us of death by removal of debris from ageing cells. And beyond de Grey there is a breed of contentious “immortalists”, among them the American physicist Frank Tipler who sees vast computer proliferation taking the whole of nature and the universe into a cyberspace eternity.

In a pacy narrative of the mind, where Descartes meets Wittgenstein and Aquinas rubs shoulders with Swedenborg, Appleyard is steering us in this age of encroaching death denial towards that inevitable question: am I a “deathist” or an “immortalist”? Do I live by accepting death, or by rejecting it? Appleyard argues in conclusion: “All our stories, myths and meanings are constructed on death, on a knowable, shared progress from the cradle to the grave . . . If we live for ever, not only will our particular loves die, love itself will die of thirst, a thirst for death.” He is, of course, profoundly right, but accompanying him on his riveting helter-skelter of a literary journey not only confirms but deepens the humane wisdom of that positive conviction.

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