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 environment, whether simulated beings have rights, and the economics of digital existence. Egan constructs an intricate world where simulated universes can be paused, copied, and run at variable speeds, raising profound questions about identity, continuity, and the substrate-independence of consciousness.

The novel is structured as a philosophical exploration disguised as hard SF, with detailed technical discussions of how digital minds might work and what constraints they would face. Egan examines the "dust theory" and other metaphysical frameworks for understanding consciousness in simulation. The work has become foundational in transhumanist and digital philosophy circles, influencing discussions of mind uploading, simulation theory, and the ethics of creating conscious digital beings.

Published in 1994, Permutation City remains influential in both science fiction and academic philosophy, frequently cited in debates about artificial consciousness and the nature of reality.