Anathem is set in a world not dissimilar from our own, but where the academic pursuit of science has been pushed to near-religious focus. Our protagonist, fraa Erasmus, wears a monkish habit and lives his life in the vast Mynster of Saunt Edhar, secluded from the outside, Saecular world. With his fraa and suur peers, he studies all manner of scientific disciplines under the tutelage of more senior avout, but these studies are almost exclusively theoretical. Within the Mynster, and in other locations like it, the avout study the learning and philosophies built up over thousands of years of research, some of which go back to earlier ages when avout were allowed to mingle with saeculars, or play with big technology.
As the story begins, the calendar is approaching Apert, a ten-day festival when Erasmus and his fellow students can leave the Mynster and Saeculars can enter it - the first opportunity in ten years. Exciting stuff! But also, the observatory in the Mynster has been closed off, without explanation. And there are a couple of Inquisitors visiting, too...
Well, I say "as the story begins", but frankly, it takes forever to actually get anywhere. I was 150 pages in and thinking, Jesus, for fuck's sake! Enough scene-setting, get on with starting the story! Stephenson's obviously got to the point where he can tell editors to piss off.
Once things do kick off, though, they're pretty good, and as the novel progresses, Stephenson cranks up the pace. Something that would have taken 100 pages earlier takes 50, then 20, and so on.
Impressively, the vast majority of this book is Dialog, according to its own dictionary: two or more avout in philosophical debate; it's a triumph that this doesn't get old, fast. Stephenson covers consciousness, evolution, religion, geometry, orbital mechanics, biology, music, quantum mechanics, computer science, language theory, and god knows what else in all of this, and does so convincingly. (Though I'd like to know what you actual scientists think of it.)
I have one issue with the plotting, which I'll mention below the cut, but aside from that, and the really slow start, and the way it bends light, I think this is great.
So: the avout examine the body at Orithena and find it's made of newmatter. From that, they infer that the Geometers must have come from a parallel universe. Um, why? The avout themselves have newmatter, in the form of spheres, cords and bolts. And they've had them for thousands of years. When it comes to the Steelyard, which is more plausible: that beings have come from another universe, or that they've come from another planet, and have been working on newmatter for longer, and without interruption?