Permutation City

Set in the mid-21st century, Permutation City opens with Paul Durham's fifth Copy waking in a simulated Sydney apartment. A Copy is a software simulation of a human brain and body running inside a computationally generated environment. The Copy discovers that his flesh-and-blood original has sabotaged the legally mandated bale-out function, a termination option required in all Copies, because the original believes his previous four Copies lacked the resolve to continue. Furious but trapped, the Copy demands to be treated as a collaborator. The original eagerly agrees, and their shared research begins.

The novel introduces Maria Deluca, an unemployed programmer in Sydney and an enthusiast of the Autoverse, a cellular automaton universe governed by simplified physics that supports its own distinct chemistry. Maria tends cultures of Autobacterium lamberti, a single-celled organism created by the Autoverse's inventor, Max Lambert. She discovers that a strain has spontaneously evolved an enzyme capable of metabolizing a modified sugar she introduced, the first example of natural selection in the Autoverse in 16 years.

Thomas Riemann, a wealthy Copy and heir to a merchant bank, lives in a virtual Frankfurt, presenting as an 85-year-old man though internally rejuvenated. Durham visits and offers immortality for two million euros: a second version of Thomas run entirely beyond harm's reach. Thomas is skeptical, and a background check reveals Durham's psychiatric history, including a decade in a ward and corrective brain surgery. Thomas hesitates to dismiss the offer because of a secret: In 1985, he killed a young woman named Anna during a violent argument in Hamburg and was never caught. The guilt has shaped his entire life.

In June 2045, Durham subjects his Copy to experiments testing the nature of consciousness. He reduces the time resolution of the simulation to increasingly coarse intervals; the Copy feels no difference. He scrambles the order in which brain states are computed; the experience remains seamless. In the most radical trial, the model is fragmented across thousands of processor clusters worldwide and scattered through time. The Copy's experience is unaffected. The Copy articulates what he calls the dust theory: The cosmos has no intrinsic structure but is a cloud of random data from which self-consistent patterns, including conscious observers, assemble themselves and construct their own coherent space and time.

A pivotal chapter reveals that the Paul who experienced these experiments was not a Copy but the flesh-and-blood original, placed into the virtual environment with his post-scan memories suppressed. His partner, Elizabeth, orchestrated the deception so Durham could experience what his Copies endured. Durham resolves to continue: He will make a new Copy, let it run briefly, then terminate it, so that its pattern of experience must find continuation elsewhere in the dust.

Durham contacts Maria and proposes an extraordinary commission, asking her to design a seed organism and planetary environment in the Autoverse capable of evolving complex life. Maria's mother, Francesca Deluca, has terminal liver cancer and refuses to be scanned. Maria accepts the commission partly because the money could fund a scan for Francesca. When a fraud investigation reveals Durham has been selling shares in a hidden sanctuary to wealthy Copies, Maria confronts him. Durham explains that he is not the flesh-and-blood original but the 23rd generation, a man whose past includes all previous incarnations as Copies. His plan is to construct a TVC cellular automaton universe, named for the mathematicians Turing, von Neumann, and Chiang: an ever-expanding grid of self-replicating processors seeded with a Garden-of-Eden configuration. In cellular automaton theory, a Garden-of-Eden state cannot have arisen from any prior state of the system; it can only have been placed from outside. The configuration will contain Copies of Durham and his 15 backers, a virtual city called Permutation City designed by architect Malcolm Carter, and Maria's Autoverse planet.

A fourth storyline follows Peer, a Copy formerly known as David Hawthorne, who died in a rock-climbing accident four years after his scan and woke in the impoverished virtual slums. His lover Kate, a fellow Copy, introduced him to the philosophy of Solipsist Nation: defining one's own reality without deference to the outside world. Peer has since used software to modify his own brain, cycling through self-directed personality transformations. When Kate reveals that Carter can hide them inside the city's code as invisible computational parasites, Peer creates a clone to stow away with her.

Thomas Riemann, after months of deliberation, creates a clone from his death-bed scan and scripts a scenario in which the dying clone briefly wakes, believing itself the flesh-and-blood Riemann. Thomas watches the recording and concludes the ritual is pointless: He cannot absolve himself through a proxy death. He delivers the frozen clone to Durham for inclusion in the Garden-of-Eden data. Maria is scanned at the Landau Clinic, and the launch takes place at Durham's flat. The program FIAT bootstraps the TVC automaton, and they observe Durham's Copy conducting 50 rapid-fire experiments to validate the system from within. After 10 hours, the money runs out and the simulation is halted. Maria deletes her scan file, and Durham deletes everything else. Durham grows manic, weeping. Maria sleeps with him. She wakes to find him dead; he has taken his own life, believing his Copy achieved immortality and the dust theory was vindicated.

Part Two opens inside the TVC universe, now called Elysium, seven thousand years after the launch. Maria's Copy wakes in Permutation City. Planet Lambert, three billion years into its evolution, teems with hundreds of millions of species. The Lambertians are insect-like creatures with nervous systems far more complex than a human's; they are conscious and communicate scientific theories through synchronized group dances. Maria joins the Contact Group preparing for first contact. Meanwhile, Peer and Kate exist as parasites within the city's code, and Thomas Riemann is sealed in a private environment, reliving variations of Anna's murder in an endless loop.

The Autoverse begins destabilizing Elysium. Durham suspects the Lambertians' coherent understanding of their world is overriding the TVC rules. Elysium is a patchwork of ad hoc simulations with no unified physics, while Planet Lambert has three billion years of consistent physical law. Durham's team enters the Autoverse and presents the Lambertians with the truth of their origins, but when Durham instructs Dominic Repetto, a later-generation Elysian, to relay the TVC rules, the Lambertians reject the theory: The TVC system would endure forever, and infinity is an absurdity their framework cannot sustain. Instead, a team of Lambertians develops field equations that explain their primordial conditions without creators. Elysium disintegrates. Permutation City implodes. Riemann's sealed environment drifts away, its own internal logic having taken precedence. Maria articulates the principle: A universe with conscious beings either makes sense of itself on its own terms, or not at all.

Peer and Kate discover the Elysians have vanished. Without the ever-growing infrastructure, their parasitic computer is finite; they are mortal again. Peer offers to dissolve his selfhood into simultaneous personalities to become a society for Kate. Durham initially refuses to join a new seed, exhausted after 25 lives, but Maria persuades him to reshape himself rather than surrender. He makes adjustments to his mental state and agrees. As failing processors spread across Elysium, Maria launches a new Garden-of-Eden configuration.

The epilogue returns to the real world. In November 2052, the flesh-and-blood Maria leaves three wreaths at the base of a trompe-l'oeil mural in Pyrmont for her parents and for Durham, all cremated. A colleague admires the painted garden and asks whether she wishes she could step right through. Maria does not answer. They walk toward a burst sewer main, and her eyes water from the stench: the mundane, irreducible reality of the physical world.