Reviews

Dispersion by Greg Egan

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wilbible's review against another edition

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challenging mysterious reflective medium-paced

Plot- or character-driven? Plot
Strong character development? It's complicated
Loveable characters? It's complicated
Diverse cast of characters? Yes
Flaws of characters a main focus? No

4.25

anthonycournoyer's review against another edition

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4.0

I would have given it more if I wasn't so clueless in math. The hardest of the hard-scifi books I've read. But it does what the genre does best, scattering bits of your mind in different dimensions.

fritzh8u's review against another edition

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5.0

This book has some really cool ideas.
I re-read at least once a year.

jbenz1213's review against another edition

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challenging hopeful informative medium-paced

Plot- or character-driven? Plot
Strong character development? No
Loveable characters? No
Diverse cast of characters? Yes
Flaws of characters a main focus? No

3.25

I once had a conversation with a friend about the inherent tension between a science fiction book being “hard” sci-fi and it being set in the far future. Hard sci-fi prides itself on logistics, on the specifics of how things work. It often extrapolates out from current technology to make educated guesses about future tech—in the case of things like The Martian, Weir barely had to extrapolate at all. But the problem is, the farther you extrapolate, the more you have to guess at discoveries that have not been made yet. How would an author, I asked, write a hard science fiction novel that extends into the distant future and compete with titans like Herbert and LeGuin?

My friend said that he had heard of this wild book, Diaspora, that I should check out.

For me, this book was a mixed bag. Some people will absolutely hate it. A very vocal minority, I expect, will champion Disapora as the best and most mind-bending sci-fi they’ve ever read. And it all comes down to the techniques that Egan uses to keep the science in Diaspora concrete, to keep our analytical brains active during the process of reading—to ensure this is “hard” science fiction.

~ Spoilers to come ~

Nothing illustrates this approach better than the opening chapter, which describes the genesis of a polis citizen—the virtual equivalent of a sentient human being—with all the flair and energy of an instruction manual. I felt like I was reading the methods section of a scientific paper here—there isn’t a character to speak of, just an omnipotent third person narrator who is describing events. Scientifically, it is admirable that Egan’s fictional method of producing a virtual equivalent of a brain is so heavily based on principles of neurodevelopment, but man, reading it felt like work. Egan is pretty good at describing scientific concepts using words alone, but his prose does often leaves you feeling like you’re reading a textbook, or in need of a figure to help you understand—indeed, Egan’s website has a bunch of Vimeo visualizations of the many interesting math problems explored in Diaspora.

Eventually, we are introduced to a world where humanity has split into three factions: Fleshers, who are flesh and blood humans like us; citizens, like our protagonist Yatima, who are sentient pieces of software running on a server; and gleisners, sentient robots. The plot finally kicks in—after a few more brain tickling math problems and a bit of worldbuilding—when a binary neutron star system collapses far more rapidly than anticipated and the resulting radiation sterilizes all of Earth’s biology, leaving only the citizens and gleisners behind. A group of citizens resolve to find out where their understanding of basic physics went wrong to prevent a similar catastrophe from happening again.

This is what Diaspora is truly interested in—the scientific questions that plague even this advanced civilization. Sure, there are characters here—my favorite, Orlando, was a flesher who was saved by Yatima after being injured just after the apocalyptic neutron star collapse. The culture shock he experiences in becoming software after being a physical being is quite interesting—I would say that he is an audience surrogate if it weren’t for other factors that I’ll get into later. But largely, characters flit in and out of the plot as needed, and are more archetypes than three- (or five-, depending on the universe) dimensional people. Yatima verself goes entire sections of the book without being mentioned. Far more of the word count is spent discussing the way that it would feel to navigate a universe with 6 dimensions, or describing in painful, intricate detail a fictional theory of physics where each subatomic particle is connected to another via a wormhole.

This is how Egan gets around the far future vs. hard sci-fi paradox—he makes up his own universal theory of physics, which he calls “Kozuch Theory.” At a certain point I thought to myself, “Is it even worth expending the brain power to understand how this *fictional* theory of physics works?” Clearly Egan, who is much, much smarter than me, has put in the work to develop an internally consistent theory here, and other people more motivated and intelligent than I would probably get a lot out of doing so. But I ended up reading just enough to understand the basics and moving on, which is a problem when this stuff is the meat on the otherwise skeletal frame of Diaspora.

And worse, at least for me, Egan seems to be philosophically advocating for this kind of interest in virtual realities, in fictional cosmologies like the one he has constructed. Yatima is a “truth miner,” someone who digs away at complex mathematical problems, isolated from other citizens, to try and uncover fundamental truths—even if those truths are based on completely contrived rules and conditions that don’t reflect physical reality. Yatima’s primary drive is to understand ver own consciousness by digging in these mines.

In the citizens’ journey through space, they discover a biological computer that, seemingly serendipitously, hosts an entire ecosystem of virtual intelligent life on a planet that is otherwise filled with single-celled, non-sentient organisms. The implicit argument here is that virtual life is as important and vibrant as physical life. (Side note—this is so, so unlikely. Where is the evolutionary pressure to encode something as intricately ordered as an entire ecosystem? What is stopping it from devolving into a mess of noise??? In all other aspects Diaspora strives to be plausible, and this is the one area where I felt like my suspension of disbelief was being tested.)

Eventually, the citizens are awakened to alternate universes, an infinite number of them, hiding in the dimensions we can’t see behind each and every subatomic particle. There’s an obvious parallel between species that live in these other universes and the residents of virtual realities. Life is life, Egan argues, and these worlds with basic fundamental laws so different from our own are worth thinking and talking about.

I have to admit, I was a bit unconvinced. The final revelation, which perfects the citizens’ theory of physics and predictably enables them to save all life in their universe, is subtle and anticlimactic. After a few fun, mind-bending chapters—and billions of years—Yatima is left alone in the cosmos, and elects to dive back into the truth mines, alone. People who are more like Yatima—people like Egan, who clearly get immense joy out of theory-crafting cerebral intricate alternate realities—are sure to love Diaspora. This is for them. For me, it was inconsistent with a piece of my personal worldview—that a key component of consciousness, and meaningful existence, is interfacing with humanity itself.

davecapp's review against another edition

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For fans of speculative hard Sci-Fi few authors compare with Greg Egan. From the outset this book posits a view of humanity split by its use (and abuse) of technology, with each group evolving or devolving to its core tenants. But as disaster of unimagined proportions threatens everything, the survival of the species becomes key.

Diaspora thus becomes a study of what could be if we were willing to risk it all.

As a side note - this was written almost 20 years ago but the early sections on the evolution of intelligent life
In the polis remain incredibly insightful.