Image of a ghost, produced by double exposure, 1899. Courtesy of the National Archives and Wikimedia Commons.

There’s a theory I like that suggests why the nineteenth century is so rich in ghost stories and hauntings. Carbon monoxide poisoning from gas lamps.

Street lighting and indoor lighting burned coal gas, which is sooty and noxious. It gives off methane and carbon monoxide. Outdoors, the flickering flames of the gas lamps pumped carbon monoxide into the air—air that was often trapped low down in the narrow streets and cramped courtyards of industrial cities and towns. Indoors, windows closed against the chilly weather prevented fresh oxygen from reaching those sitting up late by lamplight.

Low-level carbon monoxide poisoning produces symptoms of choking, dizziness, paranoia, including feelings of dread, and hallucinations. Where better to hallucinate than in the already dark and shadowy streets of Victorian London? Or in the muffled and stifling interiors of New England?

Ghosts abounded—but were they real?

Realis a tricky word. It is no longer a three-dimensional word grounded in fact. Was it ever? We are living in a material world, but that is not our only reality. We daydream, we imagine. Everything that ever was began as an idea in someone’s mind. The nonmaterial world is prodigious and profound.

You don’t have to be religious, or artistic, or creative, or a scientist, to understand that the world and what it contains is more than a 3D experience. To understand that truth, all we have to do is log on. Increasingly, our days are spent staring at screens, communicating with people we shall never meet. Young people who have grown up online consider that arena to be more significant to them than life in the “real” world. In China, there is a growing group who call themselves two-dimensionals, because work life, social life, love life, shopping, information, happen at a remove from physical interaction with others. This will become more apparent and more bizarre when metaverses offer an alternative reality.

Let me ask you this. If you enjoyed a friendship with someone you have never met, would you know if they were dead? What if communication continued seamlessly? What if you went on meeting in the metaverse, just as always?

Already, there are apps that can re-create your dead loved one sufficiently to be able to send you texts and emails, even voice calls. And if you both entered the metaverse in your avatar form, there is no reason why the “dead” avatar couldn’t continue. Truly, technology is going to affect our relationship with death. In theory, no one needs to die. In theory, anyone can be resurrected. We can be our own haunting.

Humans are terrified of death. Will technological developments allow us to avoid its psychological consequences? Or will it give us a new way to go mad? By which I mean to detach from the world of the senses into the metaverse?

And does it matter? If Homo sapiensis in a transition period, as I believe we are, then biology isn’t going to be the next big deal. We are already doing everything we can to escape our biological existence—most people barely make use of the bodies they have, and many would be glad to be freed from bodies that are sites of disappointment and disgust.

Perhaps we are moving steadily toward the nonmaterial life and world that religious folks have told us is the ultimate truth. This time around, we won’t have to die to get there—we join the metaverse.

There are plenty of horror stories about evil spirits impersonating the newly dead. I wonder if spirits of all kinds will infiltrate the metaverse? I am being playful here, but how would we know if a being in the metaverse had a biological self or not?Why wouldn’t ghosts hack the metaverse? Surely it will feel like a more user-friendly, at-home space to them. The metaverse exists, but at the same time, it occupies no physical space. Ghosts exist (maybe), but they have no physical being. Tangible reality is getting old-fashioned.

Once the hard boundary between the “real” world and other worlds comes down—and that’s what the metaverse intends—being alive matters less. Once the physical body becomes optional, where does that leave ghosts?

A ghost is the spirit of a dead person. An avatar is a digital twin of a living person. Neither is “real.” A haunted metaverse. Why not?

In a sense, the Plato sense, materialism is about the hard copy. It is impressive. But it is still a copy.

In other words, we are living in Toytown, and we mistake the substance for the shadow. The substance isn’t what we can touch and feel—and we know we are not actually touching or feeling anything; that’s an illusion. Substance may not be material at all.

Shakespeare put it this way, in sonnet 53: “What is your substance, whereof are you made / That millions of strange shadows on you tend?”

I don’t want to get into Shakespeare’s Neoplatonism here—which is what those lines swirl around—but I do want to get into the fact that computing power and AI have left multimillions of us wondering what is real, in the old-fashioned sense of the word. This will only get faster and stranger as we enter the metaverse; a virtual world with digital twins in our world—or the other way ’round, if you prefer.

“What is your substance, whereof are you made?” This could be addressed to a human. Or a transhuman. Or a post-human. Or an avatar. Or a ghost.

This essay is an adapted excerpt fromNight Side of the River: Ghost Stories by Jeanette Winterson, out from Grove Press this month.

Born in Manchester, England, Jeanette Winterson is the author of more than twenty books, includingWhy Be Happy When You Could Be Normal?, Oranges Are Not the Only Fruit, 12 Bytes, andThe Passion. She has won many prizes including the Whitbread Award for Best First Novel, the John Llewellyn Rhys Prize, the E. M. Forster Award, and the Stonewall Award.