<aside> ⚠️ Spoilers!
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I am at a loss for words in describing Permutation City. Of all the fiction books I have read (maybe even including non-fiction), this is the one that has made me think the most. It’s a masterpiece of philosophical scifi, with an extremely intricate and thoughtful discussion of what it means to be conscious, and a delightful exploration of what reality means.
Permutation City considers a world where people can scan and upload their consciousness to make Copies, which are run on remote servers. In classic Egan fashion, he gives a practical and ‘realistic’ description of server loads/quotas almost perfectly parallels the real situation with Amazon Web Services or Google Cloud. Cloned consciousness is a theme that Egan explores frequently in his short stories (see Axiomatic), but Permutation City focuses more on the interactions between clones and “originals”.
For any human, absolute proof of a Copy’s sentience was impossible. For any Copy, the truth was self-evident: cogito ergo sum. End of discussion.
The climax of the book is spectacular. I sat still for half an hour trying to process what happened – even though I probably don’t understand it well enough to explain it to someone else, just understanding the edges of the idea left me dazzled.
Unfortunately, as with all of Egan’s works, it’s difficult for me to recommend Permutation City to a general audience, as one of the central plot points regards automata theory, a topic from theoretical computer science. There may also be some red-herring story arcs, but I don’t feel that these detract at all from the intellectual grandeur of the novel. If you are willing to make the effort to understand cellular automata (Conway’s Game of Life is the classic example), and to keep a wide-open mind about the nature of consciousness, Permutation City is incredibly rewarding and among the best science fiction I’ve had the privilege of reading.
What am I? The data? The process that generates it? The relationships between the numbers?
EDIT (Dec 2021): it has been several years since I read Permutation City, but I still think about this book frequently. Definitely due for a re-read.