Are people foolish to crave everlasting life? Writer Theodore Powys' reflections on immortality capture the paradox - and downsides - of living forever, says philosopher John Gray.

"The longest life may fade and perish," wrote Theodore Powys, "but one moment can live and become immortal."

It's an arresting thought, and never more so than today when so many people are doing whatever they can to live longer. There's nothing new in the quest for longevity. Ancient Chinese and early modern European alchemists dreamt of an elixir that would give perpetual life. In Mary Shelley's novel, Dr Frankenstein pursues the dream by reanimating bodily parts of the dead.

But it is only in recent times that the dream has captured masses of people, with millions following diets and exercise regimes in the hope that they can put off dying for as long as possible. There are a few who go further - groups of immortalists, who have their cadavers frozen until technology develops to a point where they can be resuscitated or who stuff themselves with hundreds of vitamins every day while looking forward to a time when they can upload their minds into cyberspace and escape death altogether.

It would be rash to assume that such far-fetched ideas will never be feasible. We're living longer than any previous human generation, and there's no obvious limit to this process.

A more interesting question is why anyone would want to live forever. Wanting more years of healthy longevity is natural enough - which of us, if offered a pill that would ensure 30 more such years, wouldn't take it?

Wanting to live forever is different. In trying to escape death, we are attempting to transcend the natural world. Long before using technology to overcome mortality became scientifically conceivable, most of the world's religions promised some kind of afterlife to their followers.

But this only pushes the question one step further back. Why do so many religious people want so fervently to believe that death isn't the end?

Theodore Powys was a religious writer who was happy to believe that death is the end. An author once admired by some of Britain's leading writers and critics, but who until recently was almost forgotten, he was born in Derbyshire in 1875 the son of a clergyman and one of three brothers who were writers - the other two being John Cowper Powys and Llewelyn Powys, also well-known writers in their day.

Life and times of Theodore Powys Born in Derbyshire in 1875

Son of clergyman, siblings included writers John Cooper Powys and Llewelyn Powys

Shied away from modern world

Also known as TF (Theodore Francis) Powys

Set tales in exaggerated rural landscapes, reducing people to barest elements

Mr Weston's Good Wine (1927) is best-known novel - also wrote Unclay and short story collection Fables

Religion coloured his writings

Influenced by Nietzsche and Bunyan

Died in 1953 New Statesman - profile of Powys by John Gray

Theodore made an unsuccessful attempt at farming in East Anglia and then spent the rest of his life in semi-seclusion in a succession of remote villages in Dorset, where he married a local girl and devoted himself to a life of writing and contemplation. Though everything he wrote had in some way to do with religion, there is no reason to think he had any religious beliefs.

Throughout his life, he went to the village church, but when asked why answered, "Because it's quiet". His novels and short stories - fables and allegories of recurring human passions etched against a background of country life - show the influence of the King James Bible and John Bunyan, but he was also a close reader of Nietzsche and Freud. He didn't reject Christianity as much as use it to express his own, highly original view of life.

This originality is nowhere clearer than in Powys' attitude to death. Published in 1927, Mr Weston's Good Wine, his best-known novel, tells how a wine merchant called Mr Weston arrives one dull November evening in an old, mud-spattered Ford van in the Dorset village of Folly Down, accompanied by an assistant called Michael.

Mr Weston is a short, stout man dressed in an overcoat and wearing a brown felt hat under which his hair is "like white wool", who has come to the village to sell his wines. The wine merchant "had once written a prose poem that he had divided into many books", Powys tells us, only to be surprised when he discovers "the very persons and place that he had seen in fancy had a real existence in fact" - in Folly Down.

Image caption Dark wine of death, anyone?

Mr Weston turns out to be the creator not only of Folly Down, but of the world, though he lacks many of the attributes that are given to God in religious tradition. At times, he's sad and lonely, he isn't infallible or omniscient - his assistant Michael is shown as being more knowledgeable about human ways - and while he looks on the human beings he has brought into being with a kindly eye, he also envies them.

Powys never explains why Mr Weston has come to sell wine in Folly Down, but we are told that there are two good wines for sale - the light white wine of love and the dark wine of death. When asked if he drinks the dark wine himself, Mr Weston replies, "The day will come when I hope to drink of it, but when I drink my own deadly wine the firm will end."

Mr Weston may have created the world, but he wants nothing more than a human life. He and Michael - a tall, handsome fellow with an eye for the village girls - delight in the comedy and the beauty of the earthly scene.

Image caption Dead or alive: Frankenstein's monster

The wine merchant has no illusions about human beings - how could he, since he created them? He knows all about their greed and cruelty, but still he envies them. What he brings his creations is what he wants himself. At the end of the story, having dispensed his wines in the village, he is driven to the summit of Folly Down hill, where the engine stops and the car's lights go out. He and Michael talk for a while, until Mr Weston politely asks his assistant to drop a burning match into the petrol tank.

"Michael did as he was told. In a moment, a fierce tongue of flame leaped up from the car; a pillar of smoke rose above the flame and ascended into the heavens. The fire died down, smouldered and went out. Mr Weston was gone."

What human beings possess that Mr Weston lacks, until he achieves it at the end of the novel, is mortality - the very prospect of final death that religions have promised to deliver us from.

That immortal beings might envy humans is not a new thought - you'll find it in Greek myths, where the gods meddle in human affairs in order to savour something of the transient joy of mortal life. Expressing the same thought by using Christian imagery, Powys captures a paradox at the heart of our thinking about death and the afterlife - there's a kind of immortality that only mortals can enjoy.

Previously in the Magazine There are people frantic for eternal life. A few years ago I met people who were vesting their savings in the cryogenic movement - a movement that undertook to freeze your body after you were dead and keep it until such time as science came up with the solution to whatever had killed you, at which moment you could be defrosted, cured, and resume your life. Little attention was being paid to two serious disadvantages: what might the world be like when you emerged from the deep freeze, would they still have iPods and aeroplanes, supermarkets and killer heels. And secondly, why would anyone bother to defrost you when you had already paid up and had no possible means of redress? Read Joan Bakewell's full article BBC iPlayer - Beyond Belief: Immortality

Theologians and mystics distinguish between eternal life and everlasting existence. Human immortality, they say, doesn't mean going on and on in perpetuity - it means leaving time behind, and joining God in eternity. What these religious thinkers have never explained is how humans can exit from time without becoming unrecognisably different from all that they have ever been.

The immortal soul that supposedly survives death isn't the quirky, fleshly human being that we have been in life. A faded image of what we once were, it's a kind of ghost. The same is true of the uploaded minds envisioned by those who seek an escape from death in cyberspace. A computer-generated phantom floating in the ether isn't a human being, just a high-tech shadow. The shade might persist forever, but the human individual would be dead and gone.

Theodore Powys had no interest in that sort of immortality, and neither do I. Powys' delightful fable - so much more subversive of conventional religion than the sermons of the new atheists - points to immortality of a different kind, one that we can experience without losing our human identity. If Mr Weston thinks his deadly dark wine is good for human beings, it's because only creatures that live in passing time can know moments of undying value.

There are no such moments in a life that can never end. In such a life, there's nothing to treasure, nothing that has value because it cannot come again. Our lives have meaning because they are bounded by death. That's why, at the end of the book, Mr Weston chooses to join the mortals he has created and vanishes from the scene.

The paradox is that it's only because we die that we can know what it truly means to be immortal.