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Permutation City (1994) (gregegan.net)
413 points by RafelMri 4 months ago | hide | past | favorite | 203 comments



Fun to see this on HN today; I just finished it last night, on a recommendation from a friend. It was great, and left me full of unfinished thoughts -- just what you want from a good SF yarn.

For folks who enjoyed the ideas in it I can heartily recommend qntm's short story Lena (https://qntm.org/lena), which explores some of the same ideas but with a hefty dollop of (implied, but all the more intense for it) psychological horror.


Can confirm - I'm a huge fan of Greg Egan and specifically Permutation city, and also a huge fan of qntm's stories. Lena is probably the most famous, though not even the best ("I don't know Timmy" is better IMO).

Also, I finally read qntm's Antimemetics division and, while it is a bit lacking in the end, it is one of the most "oh wow this is a crazy good idea" stories I've read in years.


I'd also wager that "I don't know Timmy" is more thematically related. I feel most of the discussion in this thread glosses over what is most unsettling about Permutation City. It isn't just a book about what it could be like to be a simulated mind, it's most deeply about exploring the disquieting metaphysical consequences of computable minds. I can't think of a story that has as thoroughly scattered my basic grasp of reality as this one. Only Blindsight even begins to comes close.

In "I don't know Timmy" there's a sequence that goes:

"Well, we can't exactly turn it off."

"Why not?" asked Tim, halfway to the door, then stopped mid-stride and stood still, realising.

"Oh."

But you can turn it off without consequence and Permutation City explores the disturbing implications of why thoroughly (with a deus ex machina ending to save causal physics, as expected of an Egan story, physics is what has plot armor).


> I can't think of a story that has as thoroughly scattered my basic grasp of reality as this one. Only Blindsight even begins to comes close.

Absolutely! Very few books have also basically changed my philosophical outlook on something as much as this has (I had the seeds of the idea before the book, but the book really cemented specific concepts around computation and thought/consciousness/identity even mean).

Another book that is fairly different, but has had a big impact on some of my views of things, is the Three Body Problem trilogy (specifically the second and third book).


> But you can turn it off without consequence and Permutation City explores the disturbing implications of why thoroughly

Can you turn it off? The entire universe is 100% deterministic and the "stack" of universes in question is based on the same seed data. So if you decide to turn the n+1 simulation off, the same decision will be made in the n-1 universe. The simulation isn't running on some self-replicating automaton like in Permutation City. Of course the universe being 100% deterministic also poses the question if you can "decide" to do anything, since all decisions are already made.


The point is that if the universe is entirely deterministic then it is entirely described by its starting conditions: from the point of view of entities within it, it makes no difference if you run the simulation or not, they exist from their own perspective. Running the simulation only matters to you. So in the case where you have recursive simulations of the same universe like in the story, even if you turn of your simulation, implying the universe 'above' turns off theirs, you will continue to exist just fine, as far as you can see. That is the core idea of permutation city: they set up a simulation containing themselves and then don't bother to continue to run it: it doesn't matter to the simulated version of themselves (of course, you can ask the question whether they would need to set up the simulation in the first place. And then things get more crazy).


Make sure to read Ra as well. One of my favorite webfics. https://qntm.org/ra


It's one of my favorite webfics too, so I got a hardcover:

https://www.amazon.com/Ra-qntm/dp/B096TRWRWX

Have this in my personal library as well as a (paperback) of Permutation City. I think it's awesome they're published online but there's something special about having it in print too.


I just read the Antimemetics division and qntm's short story collection. I loved the short stories and first ~40-60% of the Antimemetics Division and felt it then got too crazy and abstract. The "magic is real" thing has new worried as I usually avoid fantasy. Do you think I'll still like Ra?


It’s as far away from fantasy as magic can probably be. I think you might like it!

In some ways, it’s even less fantastical than antimemetics, think magic as a sub-branch of advanced physics and in no way mystical.


I read Ra and I loved it, but it's imperfect. It could use an editor.

Antimemetics, being SCP-related, comes with a hefty dollop of magical realism.

Ra, to me, felt like a rocket ride as new ideas, twists, and exponentially escalating stakes get thrown at you. The pacing is very jerky, and I can very much understand if people just nope halfway through.

In particular, the characters... suck (my apologies, Sam)


Characters sucking is a common complaint about hard scifi which I can very much live with and am used to. Thank you!


While if didn’t hook me as quickly as Antimemetics or Ra, I also thoroughly enjoyed Fine Structure: https://qntm.org/structure


Thank you for this link, I’m really enjoying it.


I got a copy of the Antimemetics division too after a read through on SCP wiki. Well worth getting a physical copy to support the author.

qntm is becoming one of my favorite authors as well.


IIRC I bought it on Kindle for similar reasons.


Just curious if it repeatedly crashed your Kindle? My Kindle (Oasis 2nd gen) was very unhappy with the "redacted" black bars. When a page was full of them, the Kindle just gave up.


Nope, read it on my Kindle Oasis (I believe 2nd gen but not sure), and it was perfectly fine.


Better link to read (same story, not the first draft): https://qntm.org/mmacevedo


Fantastic read, thanks both of you for sharing this.


That's a great short story. The clinical ambience of it's description really amps it up. Real Black Mirror stuff.

I haven't read Permutation City (on my list) but I really enjoyed Disaspora by the same author (Greg Egan). Similar themes from what I gather.


More specifically, in Permutation City mind uploading is in its infancy, while in Diaspora it's a run-of-the-mill tech.

I'll add Schild's Ladder to the recommendations.


Ah, I was thinking of https://qntm.org/responsibility all along the story, and completely forgot about https://qntm.org/mmacevedo (of which lena is the draft)


On the side note - most of qntm's works have these small, interesting ideas behind them - really satisfying to read.


Egan's "Instantiation" series of short stories is also probably up a similar alley - available in his collection of the same name.


Good read, feels like it should be structured as an academic paper with made up bibliographies.


I thought Permutation City was great. One of my favorite sci-fi reads from the last couple of decades. It's probably about time to read it again, as most of the details escape me now.

Anyway, I was going to say... I've always thought that folks who enjoyed Permutation City might also enjoy Glasshouse[1] by Charles Stross[2]. The two novels aren't necessarily overtly similar, but I feel like there's a sort of abstract conceptual kinship there.

[1]: https://en.wikipedia.org/wiki/Glasshouse_(novel)

[2]: https://news.ycombinator.com/user?id=cstross


I've long wanted to read Charles Stross and somehow haven't. (Well, I read a few chapters of Accelerando years ago and never finished it, despiting liking it quite a bit.)

Do you think Glasshouse is a good place to start with his writing and is representative of his style? I loved Permutation City, one of my favorite books.

(I would've asked cstross himself but that would seem too awkward!)


Do you think Glasshouse is a good place to start with his writing and is representative of his style?

Well... to me, I'd almost divide Stross' works into two tranches: the "The Laundry Files" books, and everything else. In that regard, I think Glasshouse is fairly representative of the "everything else" tranche. But even then, there's a fair amount of variance in his works. I wouldn't, for example, necessarily compare Halting State and Glasshouse, or Rule 34 and Singularity Sky. I guess that's a way of saying that while Stross has his favored themes and topics, he's far from formulaic and I don't feel like you can pigeon-hole his "style" too narrowly.

That said, I haven't read every other work Stross has written, but I've read a pretty good chunk of them. And almost all of the "The Laundry Files" novels. Me personally, I recommend pretty much all of it. :-)

EDIT: Just realized that there's really a 3rd major tranche of works in Stross' ouvre: the "The Merchant Princes" books. I forgot about those, as I haven't actually read any of them (shame, shame, I know...). All of what I've read of Stross to date is from the "The Laundry Files" series or the "everything else" batch, minus "The Merchant Princes".


> I forgot about those, as I haven't actually read any of them (shame, shame, I know...)

It's a really great set of stories, nine in total now, and unlike The Laundry Files, a finalised / completed story arc. They evolve quite radically, from an initial portal fantasy (reporter finds herself in an apparently medieval parallel world), via trans-dimensional techno-thriller, multi-timeline developmental economics, to high-concept space war. Highly recommended.

And the Laundry Files has to be the only series I've read where vampires use agile / scrum techniques to source their blood supplies, and where an Elven combined-arms battlegroup make the Waffen-SS look like soft jessies.

Incidentally, the Laundry Files has its own separate spin-off; the New Management series. Also good fun.


Merchant Princes series is about my favorite cstross!


I love both The Laundry Files and Merchant Princes/Empire Games, and wouldn't mind seeing a high-budget TV adaptation of them.

mild spoiler

At some point there's a bloody Project Orion-type spaceship taking off the Earth's surface.


I actually have the first two or three books in that series on my shelf already, waiting to be read. Just haven't worked my way around to them yet. Soon, hopefully...


I once commented on HN how much I loved Accelerando and Charles Stross responded suggesting I read his The Rapture of the Nerds. I read it soon after and loved it. I very much enjoy the genre of people living inside computers; I welcome recommendations.

https://en.wikipedia.org/wiki/The_Rapture_of_the_Nerds


> I very much enjoy the genre of people living inside computers; I welcome recommendations.

"Ra" by qntm: https://qntm.org/ra


I think glasshouse is truly excellent, but to me it's not terribly representative of the other works (most of which I also enjoy - they're just different).


Egan has been my favorite author for years. I like his earlier works (like this one) much more than his last books. I have the impression most books he wrote and published in the last 15 years require a Ph.D. in either Mathematics or Theoretical Physics. Permutation City was my absolute gateway drug to his work and I could not stop talking about it when it first came out.

A series that explores similar ideas (although to a much smaller degree) of uploading, artificial life, and transfumanism, I've been enjoying lately is Pantheon. I just wanted to mention it here since I think you guys will enjoy it.


Zendegi is a recent book that is quite readable - but I agree regarding most of the others. Permutation City is one of my favorites but I think Diaspora must be my very favorite.


I read The Book of All Skies and quite liked it, but yeah, I basically just skimmed over the especially mathy sections. In that one the math is about (spoiler?) how gravity would work with a very unique planet, with comparisons drawn to electrostatics, I think. It was still enjoyable because it's still unique and interesting sci-fi.


I felt dumb and that I couldn't keep up also with Permutation City


My book review from last September:

> Reads like a “consciousness and computers are cool” story written by an engineer. A few incredible ideas padded by weak storytelling and philosophical exposition. Probably would’ve been better as a short story.

[0] https://taylor.town/books#permutation-city

If you like this book, I recommend Accelerando, Piranesi, Dick's Ubik, and Ted Chiang's collections.


I read Accelerando recently and it's great.

Hard to believe that it was written in 2005 given the one scene where the main character is walking around generating multiple interlocking crypto contracts to store money for his daughter.


It was published in 2005 -- actually I wrote the 9 novelettes that went into it from 1998-2003 (they were originally published in Asimov's SF magazine from 2002-2004 before I assembled and rewrote them to make the book).


Not going to lie, getting a comment from THE AUTHOR of a book I greatly enjoyed is now one of the highlights of my 10+ years of being on HN!

I should add: every time I hear the phrase "state vector" I think of Accelerando.


Thank you for your work! Last time I praised Accelerando on HN you commented that I should read The Rapture of the Nerds. I read it shortly after and loved it!

https://en.wikipedia.org/wiki/The_Rapture_of_the_Nerds


Blew my mind in the best way. Thank you.

There's a line in there that feels like it could pop up in a permutation city sequel:

> ... running a timing channel attack on the computational ultrastructure of spacetime itself, trying to break through to whatever's underneath...

Does that idea come up anywhere else in your work? If so, I'd go read it.


Scratch Monkey may have some vague notions along those lines, if I remember rightly: https://www.antipope.org/charlie/fiction/monkey/index.html


Yes, very prescient. Also the VR glasses with embedded AI and independent subagents seems almost something that you could build today.


> If you like this book, I recommend Accelerando, Piranesi, Dick's Ubik, and Ted Chiang's collections.

Thanks for the recommendations. I read and liked most of the books in your list, so I'll likely also appreciate the ones I haven't.

EDIT: I would also recommend Watts' Blindsight.


Blindsight is such an underrated gem.


Glad to see Ubik mentioned. While far from unknown, it typically takes a back seat to other works by Dick, and IMHO it's the absolute best. It is unsettling in a way comparable, although different, to Kafka.


I'll have to disagree on this one. I'm a big Phillip K. Dick fan, and have read many of his works (though it's been a while), but I found Ubik to be a slog and didn't really enjoy it.

To anyone reading this - I'm not saying don't read it - it's a beloved book! I'm just saying, if you read it and don't enjoy it, keep in mind that you might be like me and enjoy his other stuff more.


I'm with you on this, I liked the ideas in Ubik, but I found it really hard to go through it compared to other Dick works, but of course everyone is different.


Agreed. Speaking of underrated works from cyberpunk authors, you may be interested in William Gibson's non-fiction essay collection Distrust That Particular Flavor. My hot take: I think Gibson's non-fiction is much stronger than his fiction.

EDIT: Ooh, that collection includes Disneyland with the Death Penalty: https://en.wikipedia.org/wiki/Disneyland_with_the_Death_Pena...


> My hot take: I think Gibson's non-fiction is much stronger than his fiction.

Wow, that's spicy.

Will def check those out though.


Here's an even spicier take:

Although less prescient, Seveneves was a better read than Cryptonomicon.


Let's hope it is less prescient. If it isn't... global warming will be the least of our problems.


You shut your mouth! :-)

Actually, if you said the first 2/3 of Seveneves was a better read than Cryptonomicon, then maybe..


I liked the expansion of the ideas. I was bored a couple of times so it could be compressed a bit into maybe a novella half the size of the book, but a short story would have left me wanting.


No one reads Greg Egan for the character building or any of that other literary bullshit.

This is the novel that introduces the idea that a simulation universe need not have another universe simulating it. Hell, it's the only novel that has that idea. There is more insight here than we could extract from a thousand other authors, philosophers, and thinkers. But who cares, the characters were sort of cardboard and he has the whole r/menwritingwomen thing going on.


Neal Stephensons Anathem is also based on these same ideas- specifically the concepts of timeless physics, and the idea that mathematical and physical existence are identical.


Thanks. I'll put that one on my reading list. Haven't read but one of his before.


Anathem is, I think, Stephenson's best book. Definitely worth checking out.


'The Diamond Age' is my favorite, but perhaps because it's one of the rare Stephenson's that sticks the landing. Anathem is amazing, and worth reading just for the parable of the fly-worm-bat...


The Diamond Age is my next-favorite after Anathem. Both are excellent books.


read the two, had not connected the dots. Thanks!


I also recommend the non-fiction physics book “The End of Time” by Julian Barbour. It explains these ideas directly, and inspired Stephenson to write Anathem.

Weirdly, I happened to be reading all 3 of these around the same time, not initially realizing they were connected.


I justs finished reading the book and the idea that a simulation universe need not have another universe simulating it indeed baffled me. How do you make sense of that? I was disappointed there wasn't a clearer motivation for it.


(spoiler warning for others!)

Durham's "dust theory" is basically that every possible universe is simulated an infinite number of times across space and time within our universe as Boltzmann brains (he doesn't call them this but his idea of random bits of dust randomly computing things is equivalent), so actually running a simulation containing mind uploads on a computer ourselves is unnecessary to allow consciousness to exist within the simulation.

Durham describes the theory with a few more steps, like his idea of "launching" which I can't help but think Maria is correct in calling unnecessary. I think the story is trying to communicate that Durham's theory is subtly wrong or incomplete, especially when the surprising event happens at the end. I think the explanation for the surprising event at the end is (heavier spoilers ahead!) that there's a mix of Boltzmann brains running two different versions of Permutation City (one where Permutation City and the A-life universe are artificial simulations with arbitrary complicated physics and starting states exactly as we saw them be designed within the story, and one where the A-life universe is natural with a simple unified underlying physics and starting state and Permutation City is an artificial simulation/construct within it with a complicated starting state) which have been running in parallel and producing equivalent conscious experience, but by the end of the story, the latter version of Permutation City is simpler and therefore simulated in proportionally more Boltzmann brains than the first version. The latter version exists more, so when the conscious experiences of these two versions of Permutation City finally diverge, the story follows the latter version.

(I'm pretty confident in this reading of it. The story makes a regular point in talking about the complexity of the artificial simulations containing mind uploads and how much they're unlike the simple unified physics of our world. The point is brought up in a way as if the author or characters expect it to have significance; the surprising event at the end of the story is this point's significance finally being seen.)


> How do you make sense of that?

Chew on it for awhile. It's worth it. The explanation provided was sparse, but sufficient to justify.


By more insight do you mean pure speculation? I could say Liu Cixin has more insight than a thousand other minds with his Dark Forest and dimensionality, but again it's all speculative fiction.

Also, some people actually like well-written characters. I know it sounds strange.


Why Piranesi? Seems more straight up fantasy.


To me, the main distinction between fantasy and sci-fi is world-building vs. idea-exploration.

This book feels more like the deep exploration of a cool idea, which is why I'm recommending it in this context :)


Piranesi is fantasy the way Kafka is fantasy. Which is to say, kinda, if you squint. But mostly it’s allegorical.


I loved this book. It’s the sort of book that made me occasionally pause and think about the ideas presented in it. Boltzmann brains still fascinate me. The spot market for CPU power was visionary. When reading it again when I was older I only found the characters a bit weak.


> The spot market for CPU power was visionary.

Absolutely. Not to mention the use of proof of work, just 2 years after the idea was actually proposed. Very ahead of its time.


> Boltzmann brains still fascinate me.

It's ok. You fascinate them too.


Egan is the only great Australian science fiction writer I’m aware of. I principally recommend Diaspora for far future post-human history with a strong focus on physics and maths, and Quarantine which is a sort of heist thriller with a unique quantum physics hook in a relatively near future Northern Australia setting where First Nations people have gained independence and positioned themselves as an Asian financial / biotech hub.

Egan’s prose, characterisation and plotting are often weak, but almost every page has a new creative concept.


Big Fan of Egan's short stories. I feel like they are his strongest work and maybe because they can lean more on ideas. Luminous about math grad students discovering some secrets in math is pretty great.

Wang's Carpets which became Diaspora is mind blowing.

Zendegi is an interesting novel by him I never see anyone mention. I enjoyed it and the characters are a bit more developed. It also has a Eliezer Yudkowsky stand in as the big bad guy i seem to recall. Which made me chuckle.


I think of Zendegi quite often when I think about the debates surrounding digital companions, etc. I don't think the book had great commercial success.


I'm a big fan of Egan, having read a few of his books and a bunch of short stories. Personally, Zendegi was the weakest of his books by quite a bit. (Still good, just... not great.)


I’ve liked every Egan book I read but also want to mention Distress. I got shipped it accidentally when I ordered Diaspora and the seller told me to keep it.

It’s set in the “near future” so probably 2020 since it was published in 1998 and does a good job, I think, of talking about things that are happening now- third world empowerment, body augmentation, transgenders, precision pharmacy, biohacking.

And some things we don’t have yet- artificial island nations, self-autists, custom engineered plagues.

I like it because it’s one of those books that stuck with me for describing tech that “we should and one day will have” in that Egan described a “pharm” that compounds medication on the fly to precisely medicate us. For example, it will give you stimulants with your vitamix but have to counter it the next day based on how your body performs. I can’t wait for that and hate having to wait days to adjust meds. I feel similarly about Stephenson’s metaverse description and young lady’s illustrated primer, and nanodrones, and cryptocurrency. And Doctorow’s “comm” device that he described a few years before the iPhone.


Distress also has a short passage explaining the collapse of the collapse of CBDs and inflation of the suburban property market and cost of living due to remote work, set in an area of suburban Sydney that’s now not far off Egan’s predictions. Few hard science fiction authors of recent decades can pull that off, as the 21st century has shown that our 20th century science fiction tropes are either already here (computing and networking revolution, hydrogen bombs, DNA sequencing) or will likely not materialise for centuries (space colonisation, mind uploading). Egan has a talent for speculating about little details of life that illustrate a very different world.


Egan’s Diaspora is a strong book that I’d definitely recommend to hardcore sci-fi lovers.


> Egan’s prose, characterisation and plotting are often weak, but almost every page has a new creative concept.

I agree with all of that. I was thinking recently about how Egan compares to Neal Stephenson after some discussion of his (NS) fiction here a few days ago [1]. They both (imo) are weak at characterisation etc. - but to me Egan's work is among some of the best sf I've ever read [1], wheras I find reading Stephenson an ordeal. I think that's down to the depth of the ideas that Egan explores, but I'd be interested in what others think of how he compares to other authors.

[1] https://news.ycombinator.com/item?id=39287616

[2] Permutation City. Diaspora, short works in collections like Luninous, etc.


IMO, Egan's prose and plotting are not notably bad. Characters are probably his weakest point. Plus, Egan knows when to stop rambling, or rather, he doesn't ramble. As opposed to the other guy.


Greg Egan as great! Two other Australians you might try are:

Terra Nullius by Claire G. Coleman, about what it's like to be colonized.

Souls in the Great Machine by Sean McMullen, about what it's like to be part of a computer.


Also worth noting is the work of the late George Turner (d. 1997), notably The Sea and Summer and Beloved Son.


Thank you so much for recommending both authors! I'm a huge fan of Egan and would really appreciate to explore the Australian sci-fi scene more.


Diaspora is my favorite Egan book. Permutation City seems to get talked about more, but the dust theory stuff just felt implausible, and it has one of the worst sex scenes I've ever read. Maybe it's because Diaspora is less concerned with anything as abstract as consciousness and more interested in how different forms of life play out, which I find fun when it's done well.


The sex in that sex scene is supposed to be cringingly bad. Supposed to be uncomfortable to read. Did you think it was poorly done, or was it just too uncomfortable-on-purpose?


> Egan’s prose, characterisation and plotting are often weak

I sort of agree, but personally I like the rawness of it. For a similarly unrefined yet intellectually stimulating writing, check out Gregory Benford who used to be a professor of physics.


Going back a while, but I really enjoyed The Resurrected Man by Sean Williams.

I have a few other books of his, some seem sci-fi, some seem fantasy, but haven't read them yet.

Seems he's not been idle: https://en.m.wikipedia.org/wiki/Sean_Williams_(author)


Egan is prolific and his quality is quite uneven. I loved Permutation City, Diaspora and Dichronauts (although the latter had a weak story). But other books like Scale and Phoresis are downright bad. It's so hard to pick which Egan books to read because often the ones that sound the most interesting are the worst.


My standards are likely lower than yours, but while agree that his characterization is not the strongest, I do like his prose and plotting.


If they ever want to shoot an 'Even Blacker Mirror' TV anthology, they should adapt Egan's short stories. 'Axiomatic', especially.

Two stories in that collection from before the modern social internet (1992), with non-internet somewhat fantastic premises, nonetheless often come to mind when observing modern online self-presentational & affiliational dynamics:

• 'The Hundred Light-Year Diary' - a method of receiving tiny (tweet-like!) messages from the future – eventually rationed out to all people! – examines questions of free-will & (self-)deception, at many levels

• 'Unstable Orbits in the Space of Lies' - how much of what you believe/aver is imposed by your neighborhood?


Greg Egan is an acquired taste of hard SF. I would highly recommend someone who wants to get in to start here - it is short stories and some of his very best. Also one of my best cover of sci fi books

https://www.amazon.com/Best-Greg-Egan-Stories-Science/dp/194...


Agreed. He's strongest I'm his short stories. I have two collections of them.


If you like this one Diaspora seem to have extrapolated some of this ideas and went several step further (and then added much more), and Zendegi that is a lot more modest in extrapolation and tries to be more realistic (and emotional).

He have also a lot of mindblowing short stories. The collection I've read by him was Axiomatic, that had many great ones.


Permutation city is one of those books that "blew my mind". If you read sci-fi recreationaly, you know what I'm talking about. When the author introduces a novel concept which makes you think "holy crap, _what if_???" and then uses that concept to create a compelling story. It's on the top shelf in my library, along with my other favorite books.


Just finished reading Exhalation by Ted Chiang, and can't recommend it enough. It's a collection of short stories - so easy entry point for beginners as well.


I love Ted Chiang, and enjoyed Exhalation, but personally I would recommend Stories of Your Life and Others as the first book of short stories. I found it had a higher percentage of home runs.


To me anything I've read from Ted Chiang is a home run and I've basically read all his work.


My all-time-favorite collection of short stories is The Wandering Earth by Cixin Liu. Highly recommend, whether or not you liked The Three Body Problem (trilogy)


You might like Invisible Planets, Chinese sci-fi short stories compilation. I’ve read a few of them; Folding Beijing is pretty great.


Permutation City was my introduction to Egan many years ago, and since then I've read nearly everything he's written (Scale is still somewhere on my unfortunately neglected reading list, but I'll get to it eventually).

The same captivating exploration of interesting ideas is omnipresent throughout his work, and that's always been why I keep coming back. I think it's important to go into his stories with an open mind towards what literature is allowed to be - namely that it can focus on things other than narrative or characterization without being a detriment to itself. A steak does not need to be as sweet as a cake in order to satisfy a diner, after all. And that's not to say that he avoids interesting narration or character development entirely, but there are definitely stories of his where he's clearly focusing on other aspects, and the choice to do that feels intentional and appropriate to me.


Which Egan is your favorite?


It's been years since the last one I read, so it's a bit hard to recall. But the stories that have really stuck in my mind are the results of Egan tweaking some physical law, constructing a universe that might reasonably arise under those physical conditions, and then writing a plausible adventure within that universe.

Dichronauts (2 spacial and 2 time-like dimensions instead of our 3 and 1) and the Orthogonal trilogy (Riemannian spacetime instead of our "Lorentzian") come to mind. I just really like the care he puts into constructing these universes, from how planets form (the worlds in Dichronauts are infinite hyperboloids instead of spheres), to how scientific discovery progresses (as a result of the physics in Orthogonal, light of different frequencies travel at different speeds and visually separate as a common matter of course, which leads to a much earlier understanding of relativity by a fairly primitive civilization). It feels like he's building universes from first principles and taking care to consider every little consequence and detail, which leads to a lot of "Ohhhhh" moments when you encounter something counter-intuitive but then realize it directly follows as a consequence of the initial physics tweak.


I remember this book having the concept of people running at different time scales so people in “the real world” would run at 1x and simulated people would run at whatever fraction they could afford. And they could speed up temporarily to have conversations back to real world.

This made me think that sometimes our physical brains speed up and can run at 2x but still only get I/o at 1x. It will be neat that I think at some point we’ll be able to boost up to like 1000x with implants or whatnot and think about something that doesn’t require any new information and then return to the present with insight to continue the conversation.

I hope this is affordable because it will be so handy for many things. If even to just spend more time staring at the Mona Lisa and contemplating.

It also makes me wonder how people age in fiction where people can freeze time. If someone freeze time for a year, does their body keep aging biologically?


Greg Egan's Mastodon profile is https://mathstodon.xyz/@gregeganSF He's fairly active there and likes to post math problems.

I liked Permutation City, but Diaspora really blew me away. Every time you begin to get your mind around some radical new concept, Egan throws adds another fold that makes you reconsider everything you think you knew.


I think Diaspora has the best description of a valid digital identity. But I still kept thinking I’d never trust my existence to the polis/state keeping my private key private.

In Diaspora if someone steals your private cert then they become you or are at least indistinguishable to everyone else from you. I’ve never seen a super solid way to prevent this when everyone and everything is digital.


I thought asking similar lines with Altered Carbon: If you can switch physical bodies, then how can you prove you're you?

Do you have to memorise a GUID? What if you forget it? What is someone else knows yours? If there's no physical link, how is it provable?


They skipped this in Altered Carbon and it was just a “rule.”

Memorizing a GUID wouldn’t work because someone could read it from your memory.

Stephenson did this well, I think, in Dodge with the PURDAH as it was an AI trained on every characteristic of an individual through their life so it was impossible to fake. Still hand waving, but logically consistent hand waving for an id that spans consciousness transferring from biology to digital.


Pretty awesome book.

Would be cool if someone could recommend sci-fi that equally good.


Been asking myself the same question for months.

So Egan's stories are basically a mathy whodunit -- start from first (fictional) principles and eventually solve some universe-scale question or crisis. His characters are basically walking textbooks meant for info dumping / FAQing the derivations.

In that light, some similar stories I've found are...

    - Dragon's Egg (Robert Forward)
    - Of Ants and Dinosaurs (Liu Cixin, 3 body problem author)
    - The Andromeda Strain (Crichton, more medsci than math)
    - Schilds Ladder, Diaspora (other Egan stuff)
The first two are especially similar to Egan's stuff in that the only real character is the civilization / setting not the people.

I've also tried some of the more common hard scifi recommendations like Reynolds and Stephenson, but I personally don't enjoy the dialogue / scenes meant for character development. I guess it's because the stories usually take a human-scale perspective instead of taking a what-if to its reality-bending extreme like Egan does.


You should try the old master, Hal Clement. Mission of Gravity is a classic "start from first principles" story.


Hm... I didn't like Cixin or Crichton.


It’s not an easy read, but Blindsight by Peter Watts has some equally unique and compelling synthesis of scientific concepts into a big concept plot.


Blindsight is his best book, but Watts has written a lot of great stuff, I recommend all of Rifters and, for something a bit different, especially the Sunflowers cycle.


Standard internet Watts warning that the Rift novels have random sexual torture just in case you prefer to avoid that


Right, yes, especially the last Rifter book made me wonder a bit about the sanity of the author.


I read the acknowledgements in some of his books and found him rather dislikeable.


You might want to read his blog [0] to get more insight into his character. I got the impression that the author is a great and likeable human being that became rather cynical due to his disillusionment with humanity.

[0]: https://www.rifters.com/crawl/


Blindsight hit all the right hard sci-fi notes for me. I've yet to find something that scratches that same itch.


Second this recommendation. Blindsight hits much harder and faster than Egan - and in my opinion the writing is much tighter. Similar focus on science-based idea exploration, particularly in regards to theories of consciousness, brain structure, probability, and vampires. If you like Egan I'd be shocked if you didn't like watts. He is one of the hidden gems of science fiction and an absolute gift to humanity.


Semi related: If you like The Thing (1982), Watts' The Things is pretty great: https://clarkesworldmagazine.com/watts_01_10/


Brilliant fan fiction that takes a few liberties, but it would be interesting to have The Thing's perspective if The Thing was made into a series. I think in the movies was just supposed to be cosmic horror who's only real goal was to survive by spreading. Communicating with it would be pointless, unlike in Watt's story, where you have a fundamental philosophical difference based on The Thing's understanding of biology, but you could at least have a meaningful conversation with it.


Oh, boy. Blindsight was a book that made me realize that maybe I like the _idea_ of hard sci-fi more than I actually like reading it.


I think that Blindsight was extremely on depressing/grimderp/evil side.

I really like hard SF and will never again read by this author.

> Standard internet Watts warning that the Rift novels have random sexual torture just in case you prefer to avoid that

in thread next to this one is not really surprising me

Also, not really sure is Blindsight actually hard SF. It seems to be soft one at most with a lot getting close to magic with SF styling.


Maybe we read totally different books called "Blindsight" by Peter Watts because this sounds like a completely different experience than what I and most other readers have had.


The one with sort-of-vampires with epileptic effects triggered by corners, creatures capable of movement starting and completing in way their movement was not noticeable by human brain and curiously trusting people in way that ended in predictable bad ending?


Yeah the crucifix glitch is kind of silly though it does have an internally consistent explanation. I feel like maybe you didnt read the notes and references (complete with citations)? Because otherwise you would know this?

Was the ending actually bad? like badly written or bad for the characters? Personally I thought the ending was good. It felt inevitable and also positive. Humanity got to keep living and the main character reached some type of personal growth.

Anyway heres the section from the notes and references that you must not have read about the "creatures capable of movement - not noticeable by the human brain"

For example, the invisibility trick of that young, dumb scrambler— the one who restricted its movement to the gaps in Human vision— occured to me while reading about something called inattentional blindness. A Russian guy called Yarbus was the first to figure out the whole saccadal glitch in Human vision, back in the nineteen sixties15. Since then, a variety of researchers have made objects pop in and out of the visual field unnoticed, conducted conversations with hapless subjects who never realised that their conversational partner had changed halfway through the interview, and generally proven that the Human brain just fails to notice an awful lot of what's going on around it16, 17, 18. Check out the demos at the website of the Visual Cognition Lab at the University of Illinois19 and you'll see what I mean. This really is rather mind-blowing, people. There could be Scientologists walking among us right now and if they moved just right, we'd never even see them.


"bad ending" not as in "badly written" but as in "bad end" - bad things in general happen in fictional world and to this fictional characters (as opposed to "good ending" or "bittersweet ending").


Blindsight is by no means a hard sci fi book.


Somebody will always say something like this on any thread anywhere on the internet about any sci-fi. I dont know whats so attractive about gatekeeping "hard scifi" but it must be satisfying since so many people feel compelled to do so.

Regardless Blindsight is a good book and definitely has interesting concepts and good writing throughout.


Hah, well then, maybe I just don't like vampires!

In all seriousness, I thought I had seen it in a list of "top hard sci-fi books" awhile back and a quick Kagi search seems to imply that a lot of people seem consider it hard sci-fi for whatever reason.

Maybe this means there's still a chance for me.


Haha, I already read Blindsight


If you enjoyed Permutation City, you‘d probably also like „The Metamorphosis of Prime Intellect“ by Roger Williams!

It explores a similar premise of a post-singularity future (though the mechanism is superintelligence rather than cellular automata/mind uploading), but rather than imagining exactly how we‘d get there, it tries to imagine what human flourishing would look like in a world of perfect abundance!


Oh, is that the one with the incredibly explicit, and incredibly unnecessary, sex based around the authors obsession with fucking dead bodies and fucking and impregnating his daughter?

I’m very far from a prude, but JFC. Its clearly the authors vehicle to play out his fantasies, masquerading as a scientific-fi novel.


Not sure we are talking about the same book here. It's certainly quite twisted, with people taking out death contracts that allow them to die painfully (but they are ressurected by the godlike AI every time). There's also torture and other unsavoury things.

To me, this was not unnecessary, but quite fundamental to the story. Everyone was trapped by the AI who would not let anyone come to harm without their permission anyway, and nobody could die. Various people tried to push back against these constraints in creative but disturbing ways.


I was going to post the final few pages of the book here as one example, but it’s way more graphic than I remembered, so I won’t.

But nothing at all was served by us reading about how deftly the main characters 13 year old daughter blew him until he was hard enough to ride. Or the main characters musings about their two (very underage) children having sex and how he was totally ok with it. Or the long section about the wife urging him to impregnate his daughter. Or the other dozen weird-ass things in that chapter.

There’s several more examples like this in the book.

The author is not exactly the first to explore potential consequences of effective immortality, but they are one of the few who was seemingly unable to do it without repeatedly getting to multi-page, graphic, and violent, sex scenes.

Like, if one feels the need for that kind of thing, William S Burroughs and Tom Wolfe already beat that one to death decades ago.

As another example more relevant to this crowd, Altered Carbon covered the exact same subject matter, and did so without needing to write smut for teenage boys.


I confess I had forgotten the very end, where they are trying to rebuild the human race with a limited pool of people. It definitely did not need to be that graphic, although it is somewhat in keeping with the generally disturbing themes throughout.

Nevertheless, I enjoyed it as something very different to the usual sci fi fare.

I also liked Altered Carbon, although I found it read more like a hyper violent blockbuster action movie than a novel. Other than they both use ressurection as a plot device, they are very different stories. The violence in it I actually find more gratuitous than in Metamorphosis of Prime Intellect.


Oh, I was referring to the books, not the Netflix series.

I enjoyed Prime Intellect, but I enjoyed it like a mindless action film or a trashy beach book, and I’d never actually recommend it to anyone.


You could try his other writings, such as The Curators, which I just finished and can recommend. It has some sex in it but much more normal, and the violence is mostly abstract (like destroying a planet by teleporting it into its star). Available at his website http://localroger.com/ .


Thanks for the rec, but my issue is less with the book and more with the author. And his non-existent editor.


Let me share several books that brought me a similar level of awe, due to the scope and creativity of the world-building:

1. Accelerando by Charles Stross - for THE Scope.

2. Quantum Thief by Hanny Rajaniemi - for the similarly high entry threshold and rewarding experience when you cross it.

3. Revelation Space by Alastair Reynolds - for a fascinating vision of future human societies.

I'd be happy to find more books like these.


I read and enjoyed these quite a bit, so let me add a few more to the list.

- “The Fall Revolution” tetralogy by Ken MacLeod: “The Star Fraction”, “The Stone Canal”, “The Cassini Division”, and “The Sky Road”

- “Void Star” by Zachary Mason

- “Singularity Sky” by Charles Stross

- “The Freeze-Frame Revolution” by Peter Watts

- “Perfekcyjna niedoskonałość” by Jacek Dukaj

- “A Fire Upon the Deep” and “A Deepness in the Sky” by Vernor Vinge

- “The Golden Oecumene” trilogy by John C. Wright: “The Golden Age”, “The Phoenix Exultant”, and “The Golden Transcendence”

- “Gnomon” by Nick Harkaway

- the Culture novels by Iain M. Banks


Accelerando is amazing; see it being recommended several times in this post!


I enjoyed pretty much everything from cstross and Reynolds (pushing ice and especially house of suns are great stand alone).

I enjoyed quantum thief but somehow I have yet to go beyond the first book.


It's an oldie (1977), but plays with some similar ideas and I think it really holds up: The Ophiuchi Hotline by John Varley.


> Would be cool if someone could recommend sci-fi that equally good.

You could consider „Diaspora“ by the same author a good sequel a couple of thousands of years into the future where humanity is but a faint memory called „dream apes“ as living fossils in this story.


> where humanity is but a faint memory called „dream apes“ as living fossils in this story.

Dream apes are the descendants of an extreme primitivist subculture, the "statics" the protagonists visit at the beginning are baseline humans.


That sounds cool.

Thanks!


People have already mentioned qntm, but I’ll put another plug in for “Valuable Humans in Transit” https://qntm.org/vhitaos

Sol Quy with monthly short stories: https://solquy.substack.com/p/111123-the-gunslinger

Adrian Tchaikovsky’s “Children of Time” series is fantastic.

Vernor Vinge can be a bit variable, but I would start with “A Fire Upon the Deep”


Children of Time is great. Children of Ruin was a lot of fun, but I was convinced by friends Children of Memory wasn't worth it.


Children of Memory is my favourite in the series! If you liked the first two (#1 was significantly better imo), you should 100% go for the third


Have you read Gibson's "Sprawl" and "Bridge" trilogies? I read them > ten years ago and haven't read any sci-fi since, these books kinda put a subconscious "it does not get better, better diversify into other genres" attitude into my brain and personally I'm OK with that. Was reading a lot of sci-fi before that.


Novella, free to read: The Epiphany of Gliese 581

https://borretti.me/fiction/eog581

>A linguist, a chemist, and a comparative psychologist explore the ruins of a dead superintelligence.


Excellent Sci-Fi yarn, with nostalgic references. I particularly liked the VAX-11 and LISP reference ("ideograms in a formal language full of parentheses")


Yeah, this book was incredible and the tech in it has aged extremely well. Have you tried any of Ted Chiang's books? They're also great hard sci-fi. Another one that plays with similar ideas to Permutation City is the Bobiverse series by Dennis E. Taylor.


I read Bobiverse which was pretty good, at least I liked all but the last book.

Thanks!


My fav sci-fi books are:

Ubik by Philip K Dick

Dark Matter by Blake Crouch

Recursion by Blake Crouch

Highly recommended


Stephen Baxter's books are along the same lines, start with one of these:

https://en.wikipedia.org/wiki/Timelike_Infinity

https://en.wikipedia.org/wiki/Time_(Baxter_novel)


The only think I have read of Baxter is his short story Last Contact[1], but I still think about it very often. Reading the Xeele sequence is in my todo list.

[1] https://en.wikipedia.org/wiki/Last_Contact


One thing you can try when looking for similar books to one you liked, is to check Library Thing: https://www.librarything.com/work/18880

In my non-scientific assessment, it's better than GoodReads.


If you can handle the science changing since publication in the 1930s(!!!) Olaf Stapledon is simply remarkable. "Last and first men" is one of my favorite books for just how unique it is, but "star maker" has some interesting parallels


Completely different style but I think Altered Carbon by Richard K Morgan introduces lots of new ideas and interacts with them realistically.

The first season of the show was good but very different than the book.


The Netflix version is a diluted version of a rough and angry book. The idea of consciousness executed in hardware is explored, including simulated torture in subjective slow time (possibly in one of the sequels: Broken Angels or Woken Furies).


I think they also changed the societal and cultural aspects quite a bit. In the book, everything was accepted and there were weren’t any “downtrodden.” The show changed all this with the meths being super billionaires and then there being lots of poor people. And the whole thing with the rebellion.

Book takashi was an envoy super spy person with immense training that stuck with him through sleeves. Tv takashi is like a rebel/terrorist who just got some training and has personality.

In the book, it was fruitless to fight against the government because what’s the point? The tv show seems to want to make a more simple rebels vs big brother.

Still cool, but I think changed the flavor quite a bit.

Second season, of course, is rubbish and I wouldn’t recommend watching it to anyone. It’s suspiciously horrible given how good the first was.


Not sure about "it was fruitless to fight against the government because what’s the point", a rebellion is a worthwhile thing in itself. "Make it personal" [1] is almost a call to arms.

[1] https://www.goodreads.com/quotes/169549-the-personal-as-ever...


I would really like to see writers sell their work DRM free on their pages, or have an open and responsible platform that writers could use for that.

I know it is a hassle to process anything finance-related, but in my region on amazon the book is unavailable and a hard copy isn't an option for me.

It is virtually impossible for me to give money to the author for an e-reader version of the book.


Same. Not just for convenience of having drm-free ebooks but so I can have an AI read it to me.

I don’t really have a preference for audiobook performers so hate having to buy ebook and audiobook. So I’m happy just feeding a text file into a reader and listening that way.


What AI do you use for that?


macOS’ “say” command is tolerable. Edge will read documents out to me.

And I’ve also played around with speechify and natural reader, but am kind of stuck because most of the public domain I want to read already have librevox or some recording available. And I can’t feed properly purchased books without a hassle.


I agree with your wish for more DRM-free options. I don't know why a hard copy isn't an option for you. If it's just because you lack the space, then one option would be to order the physical book. Give it away. And download a copy of the book from LibGen. Author gets their money and you get a usable copy of the book.


OK, I stared at that animation far longer than I should have...

then went digging and found this other link by the same author: http://www.gregegan.net/SCIENCE/Superpermutations/Superpermu...


his mastodon presence is full of such things

https://mathstodon.xyz/@gregeganSF


A timeless classic.


I see what you did there


Egan is great. Another good book is Incandescence. Only problem is that some of his novels contain some kind of loneliness. Can't describe it.


I do not remember when I read that I was Richard Stallman's favorite book. Then I read it, and I love it.

I tried to find the citation online, but I found that Richard Stallman does not have a favorite book (https://stallman.org/rms-lifestyle.html); anyway, it is a good book with good ideas to think about.


This book rather profoundly impacted my sense of reality and the kinds of realities that can exist within sci-fi universes.


If you enjoy the 'cute bugs doing science' SF subgenre then his incandescence is definitely worth a look.

https://www.gregegan.net/INCANDESCENCE/Incandescence.html


Egan's short stories are great. Luminous is an excellent collection. I've never been huge fan of his long form novels, and will remember forever the sex scene in one of them that ends with a cramped testicle. Why Greg, why?


> Egan's short stories are great [...] I've never been huge fan of his long form novels

Same here, I love his short stories!

IMO short form works better for him because there's so much to think about, even after having finished reading a story.

If someone needs a pointer on where to start I can recommend this thread: https://redlib.freedit.eu/r/printSF/comments/x1i4bj/greg_ega...

I especially enjoyed:

  - The Safe-Deposit Box
  - Into Darkness


That scene is from Permutation City. I thought it was a nice metaphor for that character’s strained relationship with his corporeal self.


I look forward to the motion picture adaptation of this scene.


Yup, I enjoy this book.

If you enjoy it, too, might I recommend Fool's War by Sarah Zettel. It's more of a Space Opera, but some similar themes to Permutation City pop up in it...


It's great classical sci-fi. Reminds me of Lem, Watts, Dukaj. Ideas and science matters more than special effects, action and characters.


Greg Egan is the Nintendo-hard of SciFi. You enjoy re-reading many times and every time you figure out something new.


I recommended this on another HN thread last week.

Probably my favourite book of all time. I'm almost due a reread.


Great book. I've read it through twice already! I always recommend it when talking about Sci Fi


This book sent me into a four-year-long depression and existential crisis.

Best book I ever read. I guess.


Just finished it! It's so good.


loved the dust theory. really stuck with me, bit like the dark forest from three body problem


I found the concept of computational biology pretty mind blowing in the early 1990s.


Sweet site thanks


Just came here to say that Diaspora by Gregg Egan is my #1 book ever :)


It's up there for me. But I liked his Schild's Ladder, which plays with some of the same ideas, even more.


I literally was telling a friend about how the one group needed to warn the group on earth about the danger (keeping things vague deliberately!) and how they had to quickly "evolve" different entities to be able to communicate with the earth beings.

Also the different time scale awareness concept.

Such great ideas!


(1994)


I just finished it. It's extraordinary. It's awesome. It goes way beyond ideas I'd seen half assedly developed before.


What is this?? Permutation City?!




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