Quarantine (novel)

Quarantine is also a novel by Jim Crace, which was shortlisted for the Booker Prize.

Quarantine is a hard science fiction novel by Greg Egan. Within a detective fiction framework, the novel explores the consequences of the Copenhagen interpretation of quantum mechanics, which Egan acknowledges was chosen more for its entertainment value than for its likelihood of being correct.

The novel is set in the near future (2034-2060), after the solar system has been surrounded by an impenetrable shield known as the Bubble. The Bubble permits no light to enter the solar system, and as a consequence the stars can no longer be seen. This seems to be mere background at first, but in fact it is central to the plot.

The Bubble, it turns out, was constructed by aliens to prevent humanity from wreaking massive destruction on the rest of the universe, though this is not revealed until late in the story. The human brain is responsible for all causality, by collapsing wavefunctions representing systems into a particular eigenstate. Human observations of the universe were reducing its diversity and potentiality (for instance, by rendering it uninhabitable to beings that relied on stars being something other than the enormous nuclear fusion-powered furnaces human astronomers have observed them to be).

In the course of the novel, the situation is further complicated when human researchers discover a way of modifying the brain to provide conscious control over the process, allowing people to suspend wavefunction collapse at will, and to choose which state the wavefunction will collapse to. This allows a person to choose how any nondeterministic event (such as flipping a coin) will turn out, provided that he is not being observed by anyone who is still involuntarily collapsing wavefunctions. This is used to perform a variety of low-probability tricks, such as opening locked doors by simply rattling the handle and collapsing the wavefunction to the state where the tumblers just happen to slip into the open configuration.

The novel contains a number of striking ideas beyond the quantum mechanics. Of particular note is the fact that people habitually download software to run in their brains. Such "neural mods" (whose titles are always given in boldface, such as Sentinel or P3) are installed by insufflating several drops of fluid carrying genetically modified microorganisms, which in turn carry nanomachines capable of rewiring nerve cells. The story's narrator is put under control of the Ensemble, the organization that is developing the wavefunction collapse inhibitor, by the installation of a "loyalty mod" in his mind which prevents him from even thinking of betraying the organization. The narrator meets a group of other Ensemble loyalists who have discovered that their keepers have failed to specify exactly what they are to be loyal to (except by its name), and he finds freedom after a fashion by defining the Ensemble for himself. The narrator, working with the Ensemble splinter group, then proceeds to steal the software which allows humans to suppress waveform collapse.

A rogue member of the splinter group infects all of humanity with the software. (Normally, neither the microorganisms nor the nanomachines involved in installing neural mods can survive long outside the human body, but in this case the rogue scientist uses the eigenstate-control mod to modify their properties.) As a result, causality is suspended all over the globe, and the untrained humans, not knowing what to do with their newfound freedom, break down the fabric of reality.