In mid-21st century, humanity has the technology to scan a human being's brain and create a virtual copy of them who, by virtue of containing the same information as the original brain, has subjective conscious experience and views himself/herself as a continuation of the original person. Those Copies (with a capital C) live in various VR environments which run on a vast global cloud computing network, the processing power of which is bought and sold through an online marketplace called QIPS Exchange ("QIPS" stands for "quadrillions of instructions per second"). While many of the Copies have originally been terminally ill people for whom being scanned was the only chance to keep on existing, others are back-up versions of rich individuals who like the idea of keeping on living indefinitely. The class differences between different Copies are manifested in the level of detail in their virtual worlds and the speed with which they're being run.
Another endeavor which uses a large slice of the QIPS market is the Autoverse - a cellular automation designed to simulate some weird form of artificial chemistry and, through it, virtual life. The Autoverse provides diversion to a community of programmers who work on it in their spare time, their current main goal being to find a way to make the only virtual life form synthesized so far, Autobacterium lamberti, to evolve.
It seems, however, that the Autoverse junkies would have to put their hobby on hold, since a project named Operation Butterfly is buying out virtually the entire QIPS market. This initiative is meant to mitigate the devastating climate change-caused typhoons that have been hitting south-east Asia lately. It means to do so by turning the Butterfly Effect on its head - if small perturbations in a chaotic system might have a difficult to predict, far-reaching effect, then by creating a detailed enough simulation of Earth's atmosphere and oceans, one might determine which subtle changes in the water temperature might prevent the appearance of typhoons. Naturally, Operation Butterfly is a threat to the thanatophobic billionaire Copies. As beings who don't have legal rights, the world's governments might decide that the resources used to maintain their continued existence might better be redirected towards saving the lives of "real", fleshy human beings. And this is where a mysterious financial service salesman named Paul Durham enters the picture. For a fee which is pretty meager for a billionaire but large enough to buy a whole lot of QIPS, Durham offers to relocate the copies to a sanctuary in which, if his radical metaphysical theory works, guaranteed immortality is only the tip of the iceberg.
The metaphysical theory in the heart of the novel bears some resemblance to Max Tegmark's Mathematical universe hypothesis, which he has proposed four years later.
The novel provides examples of:
- Accidental Murder: As a young man, Riemann had a girlfriend from the rough part of town that his parents would not approve of, and, one day, got into an argument with her about this, which led to him throwing her against the wall, giving her a concussion, which killed her. His guilt about this, and the fact that he ran away instead of calling for help, informs his entire personality.
- Adam and Eve Plot: With all the religious symbolism that shows up in the novel, it's only fitting that it should end with Paul and Maria setting off together into their own newly-created universe.
- Artificial Afterlife: Shows up in several ways.
- People can make "Copies" of themselves through Brain Uploading, which can survive them in a virtual-reality environment. However, the original person still dies normally, and the quality of the Copy's existence depends on how much processing power their trust fund can buy for them.
- Paul Durham's unorthodox beliefs about quantum ontology and The Multiverse lead him to believe that a simulation can become real on the basis of its mathematical self-consistency, so he runs an infinitely self-organizing "Garden of Eden" model for a few seconds and then deletes it. Somehow, this actually creates "Permutation City", an alternate reality that creates itself according to the model, wherein the founding Copies are each Reality Warpers in their own, increasingly vast, domains.
- After a drastically bungled First Contact scenario causes Permutation City to unravel in a Puff of Logic, the Copies of Durham and Maria seed a new universe to escape into, making it a sort of artificial after-after-afterlife.
- Audience Surrogate: First Durham, during his experiments, then Riemann, while Durham is explaining his plan, and lastly Maria in the TWC universe. In the latter two cases, the characters think that Durham is a nutjob, and at this point, the readers can't help but agree.
- False Crucible: Durham repeatedly attempts to download his intelligence into a computer, but the downloaded intelligence always kills itself, so he (the original, human one) brainwashes himself to believe he's one of the downloaded copies, to get a better appreciation of what it's like for them. At least, this is what his devoted girlfriend explains to him when he wakes up after 'deleting' himself. After he repeats the test a few times, she ceases to exist...
- Go Mad from the Isolation: Happens to Peer and Kate, since they cannot interact with anyone else in Permutation City.
- Inside a Computer System
- Loss of Identity: Peer eventually cracks from the pressure of first living in a ghetto with those who can't afford enough QIPS, and later being stuck in the TWC universe only able to interact with one other person, that he voluntarily alters fundamental aspects of his personality in an attempt to evade boredom.
- Mind Uploading
- Reality Warper: every member of the TWC universe has complete control over their allotted piece of reality, as well as infinite processing power, since the TWC universe isn't limited by external considerations.
- Eventually the Lambertian species as a whole unknowingly gets a reality warping power: after finding a simpler scientific explanation of both the Autoverse and the TWC universe, the evolution of both universes shifts - the Autoverse becomes independent of the TWC universe and the TWC universe begins crumbling down.
- Starfish Aliens: the Lambertians, which superficially resemble insects.
- Self-Inflicted Hell: Riemann uses the TWC universe to endlessly punish himself for his prior actions. Not even Durham, with absolute administrative power, can break him out.
- The Atoner: Thomas Riemann never forgave himself for accidentally killing his ex-girlfriend decades before the story begins, and as a result his entire character arc is about his attempts to relieve his guilt. He fails, and, when he finds out that he has (unintentionally) been given true immortality and the ability to change his surroundings to his liking, decides that the only thing he can do is make himself suffer for eternity.
- The Greatest Story Never Told: Nobody in the real world will ever know about the events of the TWC universe in the book's second half. Real-world Durham commits suicide in order to ensure that his Copy will live forever, and Maria will spend the rest of her life thinking that she got taken in by an insane con artist.
- The Singularity: Shows a world in the process of transition to post-humanity (so arguably is not a true singularity) which, unlike the author's later works, actually has a lot of problems as a result, most notably, that only the super-rich can afford to actually use their Copies; all others must live in a rather crapsack ghetto until technology in the real world advances enough for everyone to have enough processing power, which might never happen. Even the super-rich can hardly interact with the real world in any meaningful way, and so become insular and quite paranoid. There is also worry from the general public that the rich will use their Copies to make a permanent aristocracy, causing regression into a Feudal Future, though this never happens.
- Unreliable Narrator: Durham spent time before the story begins in a mental hospital, meaning that it's impossible to be sure if anything he says is true. Until the TWC universe works, and everything he says is vindicated.
- Who Wants to Live Forever?: Played straight alongside characters who are enjoying immortality. Maria is not happy when she wakes up in Permutation City alone with Durham and a bunch of elderly rich people, Kate eventually thinks that she and Peer made a terrible mistake stowing away in the TWC universe where they can't interact with anyone else, and Riemann is so horrified about being forced to live with his guilt that he damns himself to hell (metaphorically speaking).
- Writer on Board: Just in case it wasn't clear what Egan's opinion on religion is, at the climax of the novel, when the Lambertians destroy the TWC universe by proposing a way that the Autoverse could have come into existence naturally, Maria comes to the conclusion that this means that a creator god is impossible even in principle, which appears to be what the whole book was leading up to. Subtle, this author is not.