Permutation City

Permutation City follows Thomas Ray, a wealthy man who purchases a copy of himself as software, and Peer, a digital consciousness created in a simulation. The narrative explores what it means to be conscious in a virtual world, whether simulated beings have rights, and the economics of digital existence. Egan constructs an intricate hard science fiction framework where simulated universes can exist independently of physical computers, raising profound questions about the nature of reality and identity.

The novel is structured around philosophical thought experiments and technical speculation about computation, consciousness, and the possibility of infinite simulated worlds. It became influential in transhumanist and digital philosophy circles, frequently cited in discussions of mind uploading, simulation theory, and the ethics of artificial consciousness. Egan's rigorous approach to the physics and mathematics of simulation set a standard for intellectually demanding science fiction.