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Comment by edanm | Hacker News Reader

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.

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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?

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!

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.

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

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

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.

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