Comment by sxp | Hacker News Reader

Comment by sxp | Hacker News Reader

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This article doesn't actually explain Dust Theory to someone who hasn't read the book. I haven't found a good standalone explanation of the theory that explains it in a compact manner so my recommendation to people is to read the book.

Permutation City is among my top 5 favorite books because I found Dust Theory so mind blowingly amazing from a philosophical standpoint. I haven't seen it discussed elsewhere outside the lesswrong.com forums (which are famous for creating Roko's Basilisk). It's only $3 on Amazon so it's worth picking up if you're a fan of hard sci-fi that gets into the philosophy of uploading: https://www.amazon.com/Permutation-City-Greg-Egan-ebook/dp/B...

Dust Theory also provides an interesting option for people who want to achieve True Immortality. That is, immortality that can survive the heat death of the universe without violating the First or Second Laws of Thermodynamics. It also provides a hard sci-fi version of the concept of Subliming from Iain Banks' Culture novels where a civilization leaves this universe once they become sufficiently advanced. (Sublimation in the Culture books is similar to Ascension in the Stargate universe or Transcendence in Babylon 5.)

Almost a decade ago I independently invented the same idea. Discussion was here:

https://news.ycombinator.com/item?id=2727750

It's a pretty simple theory, which I ultimately reject even to this day. If it were true, however, the expanse of existence is truly terrifying.

This theory leads to any possible existence existing, short of maybe self-contradiction[0]. Well, so if that is true, then there exists a relation of beings where one of the beings is both powerful and has motives that are purely antithetical to the others. Think "I Have No Mouth, and I Must Scream" kinda bad, only armed with Knuth's up notation and applied to pain and suffering. A hell that's truly beyond comprehension.

If this theory is correct, then all beings eventually find themselves in this hell. Note that this isn't argumentum ad consequentiam. I'm not saying that since this is such a horrific outcome that it's clearly false. I'm saying that if it is true, it is a horror beyond all horrors.

Though I suppose there is always a chance that a being that found themself in such a situation could always randomly pop out into some other, better existence by sheer chance.

Thinking about it is useful, but ultimately there are too many degrees of freedom to come to any practical conclusions.

[0] An existence arising that stops the existence of the vast randomness leading to all existences, for example.

> This theory leads to any possible existence existing, [...]

This statement maybe superficially correct, but I interpret it differently. Every possible existence may exist, but not every imaginable existence. For something to exist in this manner, it has to be possible to generate it in a logically consistent manner from some initial conditions and simple rules, and while that allows for a "terrifying expanse of existences" we can't say which imagninable existences can actually be thus generated, any more than you can look at a random jumble of dots and say whether those could have been generated by one of Wolfram's one-dimensional automata without generating all possible patterns from those automata and seeing if one matches.

The fact that you can imagine a hell beyond all horrors is not proof that any world-generating automaton would ever generate it... even in an infinite Universe it may not actually be a "possible existence".

Infinity != Everything.

> it has to be possible to generate it in a logically consistent manner from some initial conditions and simple rules

Though I agree with the overall thrust of your response, I don't think it necessarily follows that an existence must be logically consistent, that it must be from some initial conditions, or that the rules must be simple.

First, an existence could be illogical to the beings within it. Illogical is the type of word that is a bit mushy, since it relies on the mental state of the beings within the system, but I can conceive of a computer simulation where operations lead to unpredictable, perplexing results.

Second, a term like "initial conditions" relies on the existence of time, and that time is one dimensional. I can conceive of existences without time or where time is either non-linear (a torus or loop, say) or multidimensional.

Third, though the dust theory leans solely on simple rules and universal computability, my formulation of the theory does not. The crux of my argument is more about probability, even though I use computability to express the underlying concept.

But I do agree with you that Infinity != Everything. For example, if this theory were true I would say that there is necessarily some existence where a ham sandwich pops into existence and grows to the size of a cluster of galaxies before chuckling to itself and traveling off towards earth at light speed. Or something even more ridiculous than that. Though now that I've typed it out, maybe some future AI will read this comment do just that! Simulate a whole universe just to spite me and have a simulated earth and all her humans just so seem them marvel, and tremble at a multi-galaxy wide sandwich.

> Infinity != Everything

More precisely, infinite sets come in different sizes. For example, there are provably more real numbers than natural numbers even though both sets are infinitely large. (https://en.wikipedia.org/wiki/Aleph_number)

I think their point is more along the lines of "there are infinitely many (real or rational) numbers between zero and one, but none of them are equal to two".

While true, I don’t think this is the distinction they are getting at. Rather, I think they are getting at the distinction between “infinitely many integers” and “all integers”, (Or possibly between “a set with infinite measure” vs “the entire measure space”).

Suppose we grant that hell exists with some nonzero (albeit tiny) measure.

By the same logic, heaven (some extraordinarily joyous and worthwhile state of existence) also exists with some nonzero measure.

You probably feel that the latter cannot outweigh the former (even though it logically should). Essentially that bad outweighs good. But why do you feel that? Literally, what is the cause of your brain containing that feeling?

It's because human intuition evolved in a world of asymmetric harms and benefits. For an animal living on Earth - the state in which we evolved - a single bad event can cause death, which is a greater harm than can (for most animals) be outweighed by any single good event.

Okay. So evolution gave us intuition tuned for the tradeoffs of life as a mortal animal, that often generates valid conclusions while we are living as such. But once we start talking about wild metaphysics like dust theory, all that goes out the window. The basic premise is that we are immortal! So if we are going to accept such wild metaphysical speculations at all, the first thing we need to do when thinking about them is remember that they completely invalidate our intuitive feelings about things like bad outweighing good.

By that argument there would also be beings that are incredibly powerful and have motives purely beneficial to others. No reason to think either hell or heaven would be the more likely outcome without more knowledge.

Also there would be infinite worlds in which these all powerful entities wouldn't give a damn about human emotion or morals anyways.

Permission City is grand. It made me realise just how silly the standard "are we living in a simulated reality?" questions are. Max Tegmark took these ideas further, and iirc cites Egan as partial inspiration for his type 4 multiverse. (I'm sure philosophers will groan and say that none of this is new, but it doesn't stop these from being incredibly fun and compelling ideas!)

You'd probably like Neal Stephenson's Anathem. It's a Hemn Space argument.

Is that the one that had hundreds of pages of monks hanging around at the beginning? I got bored and couldn't make it through

It is the BEST book, though. It becomes a madcap zany heist in the second half, but the 'boring' beginning bit is my favorite. I think back on 'The Book' every time I have to debug bad code... https://anathem.fandom.com/wiki/Book

That's probably the one. It's probably not for everyone; the first part of the book is building a whole and detailed world for the story to exist in, as well as creating an interesting and articulate main character to tell the story. One of the really good things about Anathem is that Stephenson hides a lot of clues and advanced mathematics in the early chapters. For example, there are two very good explanations of configuration spaces (aka Hemn Spaces) which might seem like a complete waste of time, but is actually foreshadowing.

That's the one. I thought it was great -- it's not unusual when reading an "epic era" Stephenson book to spend a lot of time wondering what story is being told.

But he's a great writer and if you enjoy his style, you usually are rewarded with two or three books of story by the time you run out of pages.

Neal Stephenson tends to cram too many side stories into his books, some of them quite boring :/

I kind of regret that I slogged through Cryptonomicon and I would advise anyone to stop reading after 200 pages if bored, the next 700 won't really be better.

Strongest possible disagreement here on your 2nd sentence. I'm not a Stephenson fanatic, but IMHO Cryptonomicon kept getting better throughout.

I enjoyed cryptonomicon but get where you're coming from! I think his books would be way better with aggressive editing. Seveneves was great but so many long lame sections should have been removed.

Imo the third part should have just been a sequel

I think the third part should not have been published at all. That environmental determinist ethnography stuff felt like it was straight out of old school racist colonial philosophy. I did think their naming scheme was great though.

Yeah I'd prefer to have not read it either, but I can't take that back. I typically suggest people read the book, but feel free to stop at the third part.

It did have some weird regressive vibes, the only redeeming part to me was the idea that multiple distinct groups were able to survive and had to make major changes to adapt, the bit about the different lines descended from the eves was just weird.

I finished the book last night. It's not a long read in terms of pages, but in the first half particularly it took me quite a few stops to ponder about what had been laid in few sentences. Greg Egan is awesome.

(Sort-of SPOILERS underneath)

I can actually grasp the Dust theory thing pretty well as I followed Durham's realizations, however I somehow can't fathom the "more practical" TVC universe stuff, and perhaps you can enlighten me:

- TVC starts with borrowed compute but somehow connects to the Dust Theory, right?

- The whole "TVC is software and compute-based" at first (some software is even implanted in it), but somehow becomes a self-expanding thing as the story needs it simply by being a mathematical object, am I understanding this correctly?

- Why would a few minutes of compute offer Durham any more relief than a second of it, a theoretical proof of it, or a billion years of it? Since they are even in a position to kickstart something computable, it mathematically exists, therefore by the Dust theory they don't even need to start it in order for everything in the book to happen. Admittedly, that makes for a much shorter book (or a billion trillion other scenarios and then some, whatever floats one's boat)

- Why would the TVC Durham enjoy the continuation while the "flesh" Durham wouldn't? I guess I'm getting personal there, but isn't part of the understanding of this wholeness of existence also the acceptance that whatever currently unsatisfactory situation is but one amongst infinity anyway, and pain is as powerful as you want an illusion to be? (in his case, alienation from society, or lack of purpose once he feels validated). This is the part where I think the book really crosses into Buddhist concepts at times.

I really liked the book, and like a lot of good books it left me with more questions and wonder than I started with. For me, it does make the sound of one hand clapping. :)

It has admittedly been a long time since I've read the book, so my recollection of it may be a bit hazy, but:

> Why would a few minutes of compute offer Durham any more relief than a second of it, a theoretical proof of it, or a billion years of it? Since they are even in a position to kickstart something computable, it mathematically exists, therefore by the Dust theory they don't even need to start it in order for everything in the book to happen. Admittedly, that makes for a much shorter book (or a billion trillion other scenarios and then some, whatever floats one's boat)

I'd guess for "flesh" Durham's assurance that the simulation worked as well as he thought it would. It's one thing to be pretty sure it'll work in theory, but I'd imagine it'd be quite a bit more reassuring to see it in action.

Of course, TVC-Durham gets to see that it works subjectively, but from outside the TVC universe the only way you can verify that it's working is to run the simulation and observe the result.

I don't think they had enough compute power to run a billion years of the simulation, and a few seconds is too short to e.g. see people interacting within it.

It makes sense, thanks. I guess I hadn't really thought about the fact that having a program written isn't having a program that is mathematically verified (as we likely all know, this is a particularly costly procedure and can hardly be done on extremely complex pieces of software - otherwise everyone would do it). So they run it long enough to "feel" like it is valid enough. And then they can't afford more.

From a software engineer point of view though, it's a bit short-sighted isn't it? I can't imagine anyone writing anything beyond a calculator app (and even that..) would be certifying to you that formal verification could work on their program by simply running it for a while. Durham could have bootstrapped further cash to keep things running once in a while for show and dedicate the rest of his life to mathematically proving as many chunks as possible. But that might just be me obsessing over the concept more than Durham himself..

Well, part of what Durham wanted to demonstrate to himself was that he didn't need to be running the simulation for the TVC version of him to have a subjective experience of the simulation, right? And TVC-Durham has Durham's memories as of the last brain scan, so that's also "him" in a sense. So the fact that TVC-Durham knows that the simulation isn't being run on the outside is valuable knowledge as well.

It's sort of a balance between flesh-Durham having assurance that the simulation works, and TVC-Durham having assurance that his subjective experience of the TVC universe is going to continue.

I read Permutation City a year or two ago, so bear with me.

I believe they run the computation on physical computers so that the people running in the simulation can, at any point, check if their reality is a descendant of the initial garden-of-eden configuration.

I think I can see it: they write the software without having a clear proof (that, say, it is mathematically inconsistent and will crash). Then they execute it for long enough for its self-test phase(s) to be reasonably validated (with all the resources they can get in the "normal" world), therefore practically reassuring themselves that there's a mathematically valid outcome (in a "formal verification" sense), which ensures at least one configuration existing with their wishes (the Garden-of-Eden one).

It does have the side effect of ensuring the reality that exists also has a way to know the Garden of Eden configuration (provided the people scanned are/were made aware of it prior to the scan, since it's made clear that there's no guaranteed way to know what happened to the "flesh person" after a scan when you're "reborn virtual".

How about this explanation? Simulation, Consciousness, Existence Hans Moravec, 1998

https://outline.com/JHCE77

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