George Mann's Reviews > Permutation City

** spoiler alert ** [These are my updated review notes for May 16, 2021.]

I think my original review kind of holds up to the way I am still thinking about this book. I read the entire book again to try and answer some questions that bothered me the last time.

WTF does "TVC" stand for, as in "the TVC universe"? And I *swear* the Audible narrator is saying "T Bee C" not "T Vee C"... I listened to it at extreme volume and he's making a "buh" sound. I tried googling as much google and I could google, and I can't find what TVC acronym expands to. What does it?

So one other thing I still don't understand. After the book flips to the future "7000 years", is that 7000 years subjective time? Maybe they said that and I missed it. Or is that "the physical outside world 7000 years time"? Because there are few if any references that I saw to anything except what was "inside", after the time continuity jump. Are there even humans "outside" anymore? Who is running the infra?

I reject the Dust Theory even harder the second time around. I'm glad I made an attempt to quantify the possibilities. Even if my estimates were wildly off base, at least I tried! Tell me if my numbers or thought process was off by orders of magnitude please.

I still think this is an amazing book. It's really mind bending. I'm not really sure what to make of the guy who kept slamming his girlfriend's head into the brick wall, but maybe I'll appreciate that character more the 3rd time around?


[Everything below this point is what I wrote as a review on June 22, 2019.]

I'm really not sure what to make of this book. I guess I'll go read the comments and see what everyone else thinks?

/semi-snarky-review-on

After reaching the very end of this story and understanding all implications both stated explicitly as well as implied I feel I am ready to adopt a nuanced view of consciousness on the context of virtual environments.

So is it like, you can put person in computer? Is that how it goes? Like I type 10 PRINT "HELLO" 20 GOTO 10 and then I have a friend who is greeting me forever? I do see it is a person inside a hard drive but when you take off the hard drive cover who is inside!? Beep boop, there is a magic man transported into the inside of computer memory and there he say "I think therefore I am". Bravo digital man! It's like putting the horse in front of De Carte!

So more beep boop, until eventually it is massive computer and it makes it's own world and then the people inside say "oh no! I don't want to die when the janitor on the outside world pulls the power plug and all the hard drives turn down." But that is indeed the concern. Janitors within janitors, pushing around buckets full of suds water, only one awkward accidental kick of a power cord away from transcending the Lambertians and creating an internally consistent ruleset of fundamental laws that spans all the universes.

/semi-snarky-review-off

I guess what I'm trying to say is that on one hand I deeply appreciate the lengths to which Egan builds a self-evolving world and inhabitants inside who have severed their biological linkage and are free to self-determine their future in a completely unbounded way. But on the other hand C'MON please ground this book a little more in the physical world. Once the characters have transcended then their plights are ignorable and tame.. It's the struggle for life and death and reproduction that motivates us biological life forms. Without the threat of extinction, what is there to care about?

I have never read a book like this before, and I read a *lot* of sci-fi. Congrats to Egan for producing so many novel ideas and executing them so deeply. In that sense this book is a true tour de force.

I reject the Dust Theory. I think assuming that thought can be segmented into rarefied frames and executed in arbitrary order is to completely gloss over the idea that a single 'frame' of thought probably has multiple states internally executing at different tempos. The brain isn't digital. Neurons and axions and dendrites are comprised of molecules with atoms which in turn are interacting in non-deterministic ways as their cloud probability functions interact. The universe at the quantum level is probabilistic and random, and we have no reason to think the brain hasn't found ways to leverage these probabilities. In short, we are not deterministic. Low-level fluctuations in quantum states necessarily produce a level of randomness that blows away at least one, maybe two of the Dust Theory's founding assumptions.

But let's assume for a moment that human intelligence *could* be represented digitally. Now the Dust Theory goes on to have you think about how those states must surely occur *somewhere* in the universe, right? Pull out your college Thermodynamics book and start running some numerical guesses. Number of states of neurons in the brain divided by number of thought-states present in the universe. How exactly are we proposing to model a brain state from some non-brain part of the universe. Deep within the sun's core are there 10^40 atoms that happen to inhabit one specific cubic centimeter with the exact properties of my mental state right now? Oh, I'm sure there must be. Not!

I feel like the Dust Theory falls down under the slightest bit of numerical scrutiny. If you're going to base a book on such a thing, don't just hand wave your way to the punchline by saying "surely it must be so, the universe is vast!" That's lazy thinking. How vast? 88 billion light years. Take that cubed for volume. Average number of atoms per cubic centimeter across the entire universe? A few? Ignore those volumes with lower density than 1^20 atoms or so. How many do you have left? 0.000000005% of cubic centimeters within the universe with entropy low enough to possibly represent a mental state? How many of those do we have? Probably fewer than 10^62, just guessing. And how many possible mental states are there? 10^182 * 3^10000000. As you can tell by my rigorous math there is exactly a 0.00000000000000000000002% chance of the Dust Theory not being complete bullshit.

I guess I'm being lazy myself by not trying to run the numbers myself.

I think it is great how computer man and computer woman find love in the computer town even though at the end it sounds like noisy neighbors are moving in. Get off my lawn, Lambertians!