By Marina Benjamin

When the British Museum in London was in the process of acquiring its spectacular wave-form roof in the late 1990s, I contemplated donating a single triangular pane to sit among some 3,000 other non-identical panes making up the Museum’s iconic ceiling. I was tickled that my name would be engraved on a singular piece of strengthened glass and that all it would cost to bind myself into the fabric of this magnificent building was a couple of hundred pounds – the price of a pair of Eurostar tickets or a splash-out family meal. What motivated me was a feeling that I wanted to give something back to the old British Library, with its cartwheel seating and sky-blue leather chairs, where I spent many a year reading and researching.

I wonder now if my motives mirrored, on a small scale, those that drive wealthy philanthropists to donate entire buildings to the public, buildings which then (quite naturally) get named for them: the Sainsbury’s Wing, or the Sackler Gallery, or the Clore? The cynic in me thinks that philanthropists have more practical matters in view. Tax breaks, for one; brand ubiquity, for another. But if vanity doesn’t also play some small part in things, what about posterity – that tangible afterlife that one acquires not in heaven but here on Earth by having oneself, or one’s family name, commemorated in bricks and mortar? And if the buildings don’t survive, then surely the history books will remember.

Certainly there is comfort in the idea of securing posterity, of being able to swim in the stream of later generations – to linger among distant successors and become a kind of uniquely present ancestor. This is the dream of immortality re-cast in a material light, a means of extending (literally) the essence of oneself post-death without actually being physically manifest. It is about posterity as duration, not transcendence. But in a secular world, who would quibble with that?

Yet, as someone who writes books that will certainly outlast me, not least carry my thoughts and words to people I will never meet, I can honestly say that posterity is not something I actively seek. My afterlife, such as it is, will instead be a by-product of my putting something into the world that I felt motivated to undertake for urgent and proximate reasons that have everything to say to the vital present. It doesn’t excite me particularly to think that some neoprene-clad cyborg of the 23rd century will one day read one of my books and wonder what my life was like, because, quite simply put, I won’t be there.

This exact sentiment was a source of unappeasable disconsolation to an old college friend of mine who died of cancer a couple of decades back at the tender age of 33: she could not bear the idea of not being around when everyone else she knew would be. Posterity offered scant compensation. Even so, she made a time capsule of herself for her young children to remember her by, packaging up letters, select photographs and video snippets that they could cherish in later years. Perhaps this is the kind of afterlife that matters most – living on after death in the hearts of the people you love.

But if such an afterlife matters to individuals, surely there’s a version of it that rings true across societies? The problem, or perhaps it’s not a problem, just a feature of posterity, is that it is reputation-blind, for so much of what lingers does so by chance. I doubt the Paleolithic hunters responsible for the cave paintings of Lascaux, and other cave networks across Europe, ever dreamed of posterity when they daubed animal images over the walls of their dwellings in the ritual hope of a good hunt. They had danger and imminent death in view to be sure, but the dread of our own demise need not prompt a compensatory grasp for immortality. It may just strengthen our kinship bonds in the here and now, our investment, if you will, in horizontal security.

On the other hand, it’s clear that the pyramid builders of ancient Egypt were deeply invested in eternity. They were honouring kings, after all – man- Gods who insisted on having their earthly possessions and wealth sustain them in the afterlife to come – and the vast mausoleums they erected in the desert had to endure through millennia, just like their embalmed occupants.

While built-in longevity may be no guarantee of survival, I’m struck by the way that commemorative acts of monument building speak principally to the lived moment, whereas ‘legacy builds’ attempt to engender a conversation with our tomorrows. This is why Dubai’s feast of skyscrapers qualifies as a power play while Mount Rushmore’s presidential effigies are about carving a signature into time itself. It is also why former President Mitterand’s grand project – his 15 billion franc investment in revivifying Paris’s civic architecture in the 1990s – now looks like ideological artefact, whereas Danny Hillis and Stuart Brand’s ‘Clock of the Long Now’ – a futurist project that involves constructing a stupendous time piece, all precision-tooled steel cogs and gleaming chains, inside of a mountain in western Texas – symbolises a reckoning with our fate-tempting shortcomings as a species: an investment in the impossibly distant future. This kind of project renders eternity into something almost palpable, the reverberating tick-tock of a monumental timekeeper echoing through space for eons to come.

I don’t believe there is a single culture in this world that doesn’t set store by prolonging the lives of its dead as a matter of course, honouring national heroes, political leaders, pioneers, monarchs, adventurers, soldiers, scientists, and campaigners with statues and plaques, prominently placed in public squares or outside important buildings so that their deeds will not be forgotten. But it is a species-wide posterity that moves me more, especially the kind that embodies the eco-sensibilities of the Long Now and brings the future into conversation with the present as a warning and a caution against our own excesses. If eternity in its material dimensions matters at all, then it is our endangered planet that makes the greatest claim.

In this sense the eternity project I most admire was generated by British publishing tycoon Felix Dennis, who, when he died in 2014, left most of his £500 million fortune to a re-wilding project. His wish was to plant 30,000 acres of forest in Warwickshire, mainly English Oak and silver birch, but with patches of glass pools of water for wildlife and a rich undergrowth of herbaceous plants, bulbs, and shrubs. This is a project that factors time into its very realisation. It is not about staking a claim on the future – rather it is working with and towards that future. “Whosoever plants a tree, winks at immortality,” Dennis once said. I like to think that the future might one day wink back at him.