_Existence_ is best-seen as a rewrite of _Earth_, and _Earth_ was a sprawling futurological serious novel which was trying to both world-build by including countless perspectives and quotes and discussions and terms but also put them into context to build a overarching thesis. Similar to Tad William's _Otherland_ (the fantastic first book _City of Golden Shadow_, not the horrible sequels), Dos Passos's _USA_, or particularly Brunner's _Stand On Zanzibar_ (to which Brin alludes, actually, in having a alien say "what an imagination I've got.")

The overriding theme is, of course, the Great Silence. Brin's solution, characteristically for a guy who wants to be the ultimate moderate and more moderate than thou, is to take up every solution: the Great Silence is due to more efficient physical transportation *and* memetic viruses *and* Berserkers *and* Lurkers *and* panspermia *and* ecological collapse *and* nuclear war *and*... This is a little impressive to behold, and overall, I did enjoy reading the book. Brin has had a few new ideas since _Earth_ like the smart-mob.

But for the bad:

This jumping makes the book something like a huge primer on the Great Silence/Fermi's Question, yes, but *also* for something of a mess of a book. The book is huge, but a good deal of the bulk is fat and self-indulgent:

1. the dolphin sub-plot is rehashed Uplift material, which only very charitably has any relevance to anything else in the book (I thought that we would at least see them towards the end on spaceships as a token nod toward justifying the time spent on them, but no!)
2. More germane subplots feel incomplete; the autistic kids, "cobblies" and the "Basque Chimera" form one such oddly underjustified subplot - is this a thing, now, lauding crippled autistic kids as secret savant heroes? I don't know which narrative is more denigrating of the human suffering involved, the standard one or this one. (Autism spectrum may be useful in some areas, but only a *little* is necessary and even the high-functioning often fail: I read in the _New York Times_ the other day that that famous tech firm which uses autistic workers has a 5/6 rejection rate of applicants just from the start. One must sift a lot of sand.)
3. much material is borrowed from his previous nonfiction or fiction; allusions to _The Postman_ are well and good, but when I could predict the resolution of the Senator Strong mystery from the instant we were told it was an addiction... This also means that I can track how many authorial mouthpieces there are in the novel, and it's pretty much *all of them*. Even people you think are wrong like Hamish are just acting as conduits for Brin's own beliefs. This leads to the severe problem, in a repeated first contact novel, that none of the aliens were remotely alien, and the humans all seemed pretty similar to each other too. It made me wish for Stanislaw Lem, or at least Watts's _Blindsight_.

Brin also has a very weird attitude towards what he calls extropianism but most people these days just call transhumanism. For example, the bogus anti-caloric restriction argument Hamish gives; it is bogus because (a) none of those monks or monasteries are following nutritionally balanced diets, indeed, usually for religious reasons they're following highly unbalanced diets if they're not like the Taoists possibly actively poisoning themselves with mercury, and (b) the records do claim countless instances of extreme longevity, which of course we don't believe because record-keeping was terrible - which means the evidence is so worthless and biased and corrupt that we can't use it to claim the opposite either! I've told Brin this like twice before, not that he cared. But by the time the story is set, the caloric restriction question will be settled: the primate studies will be finished, the human CRers will be dead, and the underlying biochemistry (or lack thereof) will have been elucidated. Suppose he's wrong? He probably doesn't care, he's dead-set against it anyway! I was a little awe-struck when he has his mouthpiece badmouth cryonics, *after saying it worked and there had been revivals*? WTF?

WTF indeed. This attitude could be called schizophrenic. Throughout the novel, Brin seems to struggle with the fundamental problem posed by Vinge: how does he keep the story human given his belief in progress and his basic acceptance of the Strong AI thesis? He never comes up with a good answers, but blatantly hand-waves them away: an emulated rat brain goes critical and escapes into the Internet? Well, uh - nothing happens because I say so (wow, ain't it strange)! There are even more AIs pervading the world, controlling countless key functions? Well, uh - nothing happens because I insinuate something about parents and children and them being grateful! (wow, ain't it strange - ever see a grateful river, spider, tow-truck, computer...? Humans can barely be grateful, ever.) Humanity is a few decades away from a general nanofactory assembler in his story and thousands of crystal probes come to visit? Well, uh - the crystal probes are completely inactive and don't carry nanofactories or *anything* despite it being a mindbogglingly great & evolutionarily fit idea and perfectly doable for them, because I say so and it lets me write adventure arcs with primates fighting over & chucking around glowing rocks! (wow, ain't it strange) He'll mock the extropians in the first part for believing in cryonics or uploads or AIs even though their most-criticized belief, cryonics, has been vindicated 100% in his story even beyond their hopes, their expectations of uploads are equally justified by events towards the end - non-destructive uploading, even! We'd settle for destructive uploads at this point... and so on and so forth. Well, uh - they're right but they're wrong, don't you see! (wow, ain't it strange)