Permutation City is a science fiction novel (ISBN 1-85798-218-5) by Greg Egan which explores quantum ontology via the various philosophical aspects of artificial life and simulations of intelligence. It won the John W. Campbell Award for the best science-fiction novel of the year in 1995 and was cited in a 2003 Scientific American article on multiverses.
Permutation City asks many of the same kinds of philosophical questions as other works such as The Matrix, Blade Runner and Ghost in the Shell, as well as other cyberpunk and postcyberpunk works – is there any difference between a perfect computer simulation and a "real" person? – but its textual nature allows it to push the ideas further. Egan gleefully deconstructs and undermines traditional notions of self, future, personality, and even physical reality. It also displays Egan's "dust" theory of existence, which postulates that our universe is but one instance of an infinitely configurable data pattern being run on a universal computational substrate.
The book opens with a 20 line anagrammatic poem, in which all lines are anagrams of the book's title.
Another interesting idea expressed in the novel is that of the Autoverse, a virtual chemistry for a virtual world (possibly an advanced version of Conway's Game of Life, containing thirty-two chemical components/elements), but which are "easier" to computationally model than real chemical elements. Another way to phrase this is that the Autoverse is the simulation of a small universe. But the Autoverse is different from our real world because it is much simpler. Egan still had self-consistent laws and nature in the Autoverse. For example, there is a simple Autoverse physics, Autoverse chemistry. A major plot grows out of the creation of a primitive form of life, Autobacterium lamberti, forming the basis for Autoverse biology. Maria, a computer hobbyist designs the Autobacterium lamberti as a bacterial-like organism that is able to evolve (i.e. is susceptible to natural selection) when conditions for its existence become unfavourable. She does this using virtual presence software, ie:a piece of software that allows you to have complete control over aspects of the computer simulated virtual mini-universe. The computer then creates a world capable of modelling objects as complex as bacteria, down to the level of individual atoms.