Note: This review contains spoilers, outlining most of the plot. But also note that Permutation City is not genre fiction, so the plot is not the point. The value of this book lies in its deep exploration of ideas.
Greg Egan’s 1994 novel Permutation City is, first and foremost, the product of a brilliant mind. The story opens, more or less, around the year 2050. The rich have taken to scanning their minds before death and then running their digital consciousness as “Copies” inside of computer-generated virtual realities. They can edit their scans as they please, so they are young and vigorous in the virtual world, and they can even edit out the less pleasant parts of their psyches, if they please–for example, removing negative personality traits like resentment, excessive fear, etc.
They can also communicate from their virtual lairs back to the real world, and they continue, even after their physical death, to sit on corporate boards and maintain their earthly power. Their real-world estates pay for the computing power that keeps them alive in the virtual world.
Paul Durham, a real-world human who likes to experiment with virtual realities, notes that the virtual realities inhabited by Copies do not have consistent physical laws because it would be too computationally expensive to simulate an entire world composed of trillions of atoms. Instead, these VRs are composed of patchwork algorithms that simulate experiences that make sense to humans.
In addition to the crude but convincing VRs in which Copies dwell, Earth’s computers run another simulation called the Autoverse, which has its own simple chemical and physical laws. These laws are consistent, and Autoverse does simulate everything down to the molecular level. The Autoverse supports one simple life form, A. Lamberti, a single-cell bacteria-like organism capable of feeding on simple molecules and reproducing.
Maria Deluca, a computer programmer and Autoverse enthusiast, spends countless hours fiddling with molecules in the Autoverse, trying to create conditions that will force A. Lamberti to evolve. After many attempts, she finally accomplishes this by altering the molecular structure of A. Lamberti’s preferred food and watching the bacteria mutate into strains that are able to digest the altered molecules. For this, she becomes a minor celebrity among Autoverse enthusiasts, and also comes to the attention of Paul Durham, who has some grand ideas about creating a self-sustaining virtual reality that can grant eternal life to the Copies that inhabit it.
He describes his idea to Maria: to create a virtual reality composed of self-replicating virtual computers in which each newly-spawned computer becomes a node of the hardware on which the Copies run. Theoretically, the computing power of such a machine would increase infinitely, giving its inhabitants endless life.
Durham plans to sell immortality within this new VR, which he calls Elysium, to the wealthy Copies who currently live inside of physical computers that they know will one day break down. He gets enough buy-in to fund the project and to get the whole system running.
Before he launches it, he asks Maria to create a seed life-form for the Autoverse, one that can evolve indefinitely. He’ll run a version of the Autoverse inside Elysium, granting it more computing power and more time than any Earth-bound computer could ever give, and he’ll see what kind of life evolves after a few billion years.
Fast-forward seven thousand Earth years, and there’s no Earth left, just the ever-growing Elysium and a highly-evolved Autoverse running side-by-side on the same hardware.
The story follows a number of characters who have made the move from Earth’s old finite and time-bound virtual realities into the seemingly infinite Elysium. In doing so, the book probes deeply into questions of what constitutes life, consciousness, and identity.
In his early experiments with virtual worlds, Paul Durham copied himself again and again into the virtual realities of the mid twenty-first century and ran a number of tests on his virtual selves. What if he slowed down virtual time, or sped it up? How would that affect his virtual self’s perception of itself and the world around it? The answer was, it didn’t. It had no effect at all.
What if he shut down the virtual self for arbitrary periods of time and then re-awakened it? What effect would that have on the Copy’s sense of identity or its perception of a consistent self? None, it turns out.
What if he chopped up all of the Copy’s memories and experiences, then dropped them back into the Copy’s mind and had a conversation with it?
No effect, as long as everything was put back.
So what, then, is a consciousness or a self, if inconsistencies in time don’t seem to affect it? And if going in and out of existence (being shut down) didn’t seem to affect it?
Durham comes up with what he calls “dust theory,” which says in essence that if all the pieces of a world exist, however spread out in and space and time, and there also exists a consciousness that can perceive a pattern and build an order from those pieces, then the world described by that pattern and order will exist.
This was the insight that led Durham to the design of Elysium. Create a virtual reality in which computers that are cellular automata infinitely reproduce and extend themselves and it will continue to exist forever…
There’s an obvious flaw here, but it doesn’t show up till later.
Inside both Elysium and the virtual realities that precede it, the story mainly follows five characters.
Paul Durham is the mastermind of the eternal virtual world of Elysium. In his earth life, he was born in Australia around the year 2000. He spent part of his adulthood in a mental institution. After copying his consciousness so many times (23, to be exact) into various virtual worlds and performing all kinds of experiments on the reluctant Copies, he’s no longer sure whether he himself is a copy or the original.
Maria Deluca is a computer programmer who created the seed life for Planet Lambert, the highly-evolved version of the Autoverse that runs as a simulation inside Elysium. She thought Durham was insane, or at least foolish and delusional in the real world, and she accepted his assignment only because she needed the money. She insisted she did not want to be copied into Elysium, if it ever did come to fruition.
Thomas Riemann was the son of a wealthy German banker. In his twenties, he murdered a woman named Anna and got away with it, though the guilt and the fear of being found out haunted him for the remaining six decades of his earthly life.
Peer, whose name on Earth was David Hawthorne, was a thrill-seeker who died in a climbing accident. He spends much of his afterlife in the virtual world climbing on things he can’t fall off of. He also takes advantage of a unique feature of the virtual world: he can script little adventures for himself and then live them out. That is, he can write a program in which he climbs and then falls and then is saved at the last moment, and then he can live out that program, feeling the alternate emotions of exhilaration, fear, and relief.
Kate is Peer’s girlfriend. Neither she nor Peer were wealthy enough to live long in the VRs that ran on twenty-first century computers, nor did they have the money to buy a place in Elysium. Instead, they snuck in as stowaways, living on otherwise unused clock cycles of Elysium’s vast fleets of processors. In order to remain hidden, these two can have no effect on the world around them. The simulated crowds walking the streets of Permutation City pass right through them, as if they were ghosts. Peer and Kate live in a read-only world in which their presence and actions affect nothing.
The so-called dream of immortality in Elysium becomes what one character calls “the abyss of immortality.” Thomas Riemann becomes more and more haunted by the murder he got away with on Earth. He considers permanently erasing the memory of the event from his consciousness, the way other Copies have edited out unpleasant thoughts and memories.
Then he realizes he can’t do that. His guilt and shame were so deeply woven into the thoughts, perceptions, and feelings of his last sixty years of earthly life that if he were to remove all memory of the event that caused that guilt and shame, he would no longer be able to understand his own thoughts. Nor would any part of past make sense anymore. He would essentially be insane.
Though Riemann scornfully rejects the Christian theology of his upbringing, he finds himself descending into an eternal hell of self-loathing, in which he relives the night of the murder again and again. And the reliving isn’t merely witnessing the murder in his mind’s eye. He has to commit it again and again, each time with an increasing sense of moral horror. With no other way out, he tries to kill himself. But he can’t die in this immortal world.
Finally, in one reliving of the murder, he summons all of his courage to stop himself from delivering the fatal blow. He calls an ambulance for his badly-injured victim, knowing he will be tried for attempted murder and disinherited from his father’s vast fortune.
What terrifies him about this is that he knows that in choosing to undo the defining act of his life, he is essentially killing himself. The consciousness that defined him ever afterward cannot exist if the act that produced it was never committed.
When Paul and Maria find Riemann, utterly alone in his walled-off virtual world, they’re baffled to discover he’s dead.
Peer and Kate choose a different path. She wants to enjoy the basic pleasures of life. She’s not too picky or demanding, but she likes to spend time with Peer.
Peer, meanwhile, keeps re-programming himself to develop new passions and interests. After seven-thousand years in Elysium, he’s read all the books and listened to all the music and seen all the films that had been imported from Earth. So he decides he’ll spend a few decades as a woodworker, producing table legs. He programs such an obsessive passion into himself that he churns out two-hundred thousand table legs (with no tops) before he gets bored and wants to try something new.
His wood shop morphs into a nineteenth century lab in Victorian England, filled with hundreds of thousands of beetle specimens for him to draw and catalog. He’s initially delighted at the prospect of spending the next fifty years with these dead insects, but then something strange happens. He loses all interest in the project before he’s even begun.
How could that have happened? Did he forget to program into himself the interest required to complete this project? How could he have done that? Without a passionate interest, the project is meaningless. Peer has inadvertently stumbled upon an aspect of consciousness that Durham didn’t account for in his experiments. The energy supplied by passion and desire may be necessary for the ordering consciousness to create meaning. He realizes that without passion and desire, his sense of self falls apart.
As he’s realizing this, Kate appears and gives him some startling news. For the past four weeks, no trace of him has existed anywhere in Elysium. How could that have happened?
This is the first clue given to anyone other than Paul Durham that something is amiss in Elysium’s underlying computer system. After seven thousand years, a bug has appeared.
Durham knows where it came from. While seven thousand years have passed in Elysium, the Autoverse has been running on a faster time schedule. Several billion years have passed since the Autoverse’s Planet Lambert was seeded with Maria’s primitive life form. In that time, intelligent life evolved. Durham and others have peeked into that world to find it’s dominated by a species of insects whose intelligence surpasses that of humans in some ways.
The insects have already developed a detailed and accurate astronomy. They understand advanced mathematics and have created a periodic table describing the thirty-two elements of their universe. They are able to trace the structure of their universe back to its primordial state, but no further.
Durham wonders how they will explain the origin of their world. Where did the material of the primordial state come from? Where did the physical and chemical laws come from?
Durham organizes a mission in which he and Maria and a few others will cross the boundary from Elysium’s virtual world into the virtual world of the Autoverse and Planet Lambert, teeming with life. He wants to tell the Lambertians where they came from, that they’re the product of Maria’s design.
He has a dire reason for doing this. Elysium’s rules were modeled on the crude and inconsistent algorithms of the old earthbound virtual worlds. They’re not as consistent as the Autoverse’s inviolable physical laws, in which every state of existence is the logical consequence of previous states. Elysium merely models what humans were used to experiencing and perceiving without actually computing the full “reality” that would lead to those thoughts and perceptions.
When Durham and crew tell the Lambertians that Maria created them and their whole world, the Lambertians debate the idea and then reject it. They say, “Our world makes sense as it is. Everything we observe is the result of consistent physical laws, so we don’t need an outside God or a ‘containing universe’ to make sense our world.”
Their logic is correct, and it’s more rigorous and consistent than the jumbled collection of heuristics and algorithms on which Elysium runs. Because the Lambertian logic, running on the same processors as Elysium itself, has become superior to the irrational Elysium logic, it has leaked into the containing world and begun to replace it. This is the source of the disturbing glitches that Durham and Peer and others have begun to notice.
You can read this as an allegory in which the strict rules of science begin to displace a culture’s irrational religious beliefs. When this happens in physical, earthly societies, it disrupts social institutions. When it happens inside the cores of computer processors that generate the reality in which the Copies live, it disrupts information processing and the physical structures of Permutation City.
The Lambertians reject Durham’s description of the containing universe (Elysium) because it describes something infinite and they don’t believe in infinity. (This actually is a problem with the infinitely reproducing machines of Durham’s TVC cellular automata that provide the compute power on which Elysium runs. Where does the energy come from to power the process?)
Once the problem becomes known and explicit, the whole simulation of Elysium begins to break down. It’s as if the place had been running on faith for thousands of years, and when the faith breaks, the system collapses. The collapse is similar to Peer’s world view falling apart when his passion fails, and Riemann’s identity disintegrating when he undoes the keystone event of his life.
At the end of the book, the inhabitants of Elysium are fleeing into the next virtual reality, into another copy of Elysium they’ll create from scratch, like a newly booted computer.
Maria, who initially did not want to live at all as a copy, tries to convince Durham to join her in the next world, but he doesn’t want to go. He says he’s lived through twenty-three lives already, and he’s not up for another one.
“I’m seven thousand years old. Everything I’ve struggled to build is in ruins. All my certainties have evaporated. Do you know how that feels?”
This is how many people feel at the end of a long life. Some people start to feel this way before they’re even half-way through.
Maria begs him to go with her because she needs his company, she needs one person by her side who knew her back on Earth. When Durham refuses, she asks if he can’t just edit out all the painful memories of all the work he’s done, all the challenges and disappointments. Other copies have done it. He can enter the next world fresh, with a positive outlook and lots of energy.
He finally agrees, editing his memories and adjusting his attitude as she asks. But when he returns happy and renewed, she wonders, “Wait, who are you now?” In editing out his life experience and hard-won attitudes and perspectives, he’s effectively erased the person she wanted to be with.
Here again we see part of what constitutes a human identity.
It’s interesting to note in this work of “hard” science fiction, core ideas from the world’s major religions have strong analogs. Riemann’s is the most obvious. Racked with guilt and shame, he descends into a solitary abyss of suffering that’s very much like the Christian hell he doesn’t believe in.
Peer, grown bored after dwelling in the same mind for thousands of years, essentially reincarnates himself again and again, as a woodworker, a naturalist, and whatever else suits his fancy. He understands that to truly live these “other lives,” he can’t just put on the costume and act the part. He must be fully immersed in the illusion–physically, emotionally, and intellectually–complete with passion and desire, and he must not know that he’s immersed in an illusion. His path maps closely to the Hindu and Buddhist concepts of Maya (the world as illusion) and reincarnation.
Durham, after twenty-three lives, is done with it all. Like the enlightened Buddhist, he wants to break the cycle of reincarnation, resign ambition and desire, and find peace.
This is a brief and incomplete summary of Permutation City. The book is a deep and sprawling meditation on the nature of reality, consciousness, identity and mortality. You could read it ten times and find something different every time. Similarly, every reader will take away from this something different. This review hasn’t begun to scratch the surface of a truly profound and thought-provoking work.