Permutation City

by Greg Egan

Other authorsChris Moore (Cover artist)
Hardcover, 1994



Call number

PR9619.3 .E35


Millennium (London, 1994). 1st edition, 1st printing. 304 pages.


The story of a man with a vision - immortality : for those who can afford it is found in cyberspace. Permutation city is the tale of a man with a vision - how to create immortality - and how that vision becomes something way beyond his control. Encompassing the lives and struggles of an artificial life junkie desperate to save her dying mother, a billionaire banker scarred by a terrible crime, the lovers for whom, in their timeless virtual world, love is not enough - and much more - Permutation city is filled with the sense of wonder.

User reviews

LibraryThing member JanetinLondon
I haven’t read many books like this before, so I don’t really know what to say about it, but I’ll try. It’s a book where the ideas are more important than the story, and, while this can be mind expanding, it’s also ultimately very frustrating, because, for me, good fiction is about human issues (or human substitutes – animals, aliens, whatever). I think those get very lost here, principally because the author doesn’t actually care about them.

Imagine what would happen if our whole personality could be “scanned in” to a computer and encoded as a piece of software, to the point where it could actually make decisions about how to interact with its virtual world. Think avatar, but to the nth degree. In this near future, that is possible, but requires such immense computing power that, as yet, only a handful of dying super billionaires have done it, and they “live on”, enjoying any virtual worlds they like, and still controlling their vast wealth, to ensure they continue to be able to afford this forever. Of course, the future is never certain – will there be a political backlash? Will computer time become too expensive? Will the earth be destroyed, or abandoned? One of the protagonists devises a scheme that will create a virtual world with molecules that can mutate, hoping that eventually (as in, billions of years) this will develop to the point that natural selection starts to work, evolving a “world” independent of any computer (the science got way beyond me at this point, I’m afraid). As well, people can create copies of their software to live in different virtual worlds, as a sort of insurance. There’s a lot of this sort of thing, including what would happen if you lost your wealth – would you just get less and less computer time? – could you “hide” your software code in the cracks, sort of like those annoying ads that pop up if your browser is slow in getting to its destination, in effect becoming an unseen “squatter”, and so on. All very imaginative stuff, which I did find fascinating to think about even though I had to skip over quite a bit of it.

The problem comes when the author tries to build in human/moral/emotional stories. One character was an unexposed killer in “real” life – can he escape his guilt? Is it even “his” anymore? Another is desperately trying to raise money to allow her dying mother to be scanned, which the mother is resisting – what are the emotions involved? What will “people” actually do with all that time? What do “self” and “identity” mean if you can’t be sure whether you are the original or a copy? And how could you tell? All these interesting questions are introduced, via potentially interesting characters, but none are fully developed or resolved. I found that very frustrating, and it knocked down what could have been a great read to just okay for me. If I want to read about the potential for AI I can read a science book, but a novel needs to do something different.
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LibraryThing member Lyndatrue
It isn't as if there were no other reviews, and normally, I don't review anything that has a bunch of reviews already. I'm just poleaxed by the book, and the ending. I almost started reading it again, but stopped after the first few pages. Life is short, and there are other books. I'll still return to this, sometime down the road, just for the pleasure of reading it, all over again.

It's excellent, and believable.
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LibraryThing member mentatjack
I read this when it was released in 1995 and still have my copy. It unerringly makes my list of top 10 speculative fiction works.

At this far of a remove, I don't remember the details beyond modeling a slightly simpler universe inside of a computer, but It opened up a new world of science fiction for me. This was one of the first science fiction books that I read the year it was published, and thus the first without the "past looking forward through a present not my own" feeling that Asimov and Heinlein and many others gave me.… (more)
LibraryThing member fpagan
An important fictional exploration of mind uploading; I should have read it long before 2007. Complicated, and a whale of a tale.
LibraryThing member Cheryl_in_CC_NV
I didn't particularly care for the book - too much complexity in the plot and too little understanding of characters and motivations.
LibraryThing member antao

(Read originally in 1994).

I was six years old when my parents told me that there was a small, dark jewel inside my skull, learning to be me"...

">Learning to be me

With this starts off one of the most astonishing short stories I've ever read. If you haven't read it, I urge you to do so. Egan questions what it really means to be human in a way that it's quite unsurpassed in my mind.

I've just finished "Permutation City", and the feeling I got from reading it now is the same I got in 1994 when read it for the first time.

Is it possible to write a book exploring the dichotomy between a computer simulation of a person and a "real" person? More specifically, is it possible to focus on exploring one possible model of consciousness and reality? (YES, It's possible!!!)

The Dust Theory upon which the book works is based on Tegmark's mathematical universe hypothesis (MUH). The assertion states that our external physical reality is a mathematical structure. Without going into much detail, the following article is great to start grasping the concepts that underpin the book:


Without the proper conceptual framework, I admit it's difficult to get into the book. But as one understands the questions lurking behind it, it's one hell of a ride.

Other Computer Science concepts needed to deeply appreciate the book:

1 - The assumption that human consciousness is Turing computable, ie, all aspects of genuine consciousness can be produced by a computer program. Egan tries successfully to deconstruct not only some standard notions of self, memory, and mortality, but also of physical reality;

2 - Cellular automata. In this book VR assumes the form of The Autoverse, which is basically a deterministic chemistry set, internally consistent and vaguely resembling real chemistry;

3 - VR making extensive use of heuristics to simulate completely immersion and convincing physical environments, but at a maximum of seventeen times slower than "real" time.

The three ideas above are at the core of the book. Not even William Gibson nor Neal Stephenson explore these concepts the way Egan does. His ideas are way, way bigger than Gibson's or Stephenson's. He's thinking way bigger. He's asking questions that start in the real world and run right past the border to metaphysics and philosophy using Computer Science constructs. I look back and wonder if there was ever a line at all.

Despite the fact that it makes some demands on the reader, namely Computer Science Literacy, the book feels absolutely real.

Greg Egan is really one of a kind. He deserves a wider readership, not being pinned down to SF.

Computer Science apart, his work is so pure that it resonates. I'm going to reread all of his work. I'm in for a ride.
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LibraryThing member ohernaes
Mind-boggling novel about personal identity and artificial life and evolution. Complex and difficult to follow at times, but recommended nonetheless.


Original language


Original publication date


Physical description

304 p.; 8.3 inches


185798174X / 9781857981742
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