Just think about it

Anathem

A Novel

Neal Stephenson

William Morrow: 936 pp., $29.95

WHEN C.P. Snow delivered his famous lecture on the "Two Cultures" in 1959, he pointed out that the sciences and the humanities seemed to be running along increasingly disconnected tracks. But what if these two cultures were separated not just by differences in principles, interests and standards, but were physically divided as well?

"What if?" is the purview of the science-fiction novelist, and in "Anathem," Neal Stephenson, newly finished with an extended foray into the realm of historical fiction ("Cryptonomicon" and the massive three-volume Baroque Cycle), answers that question by returning to the genre he calls home. "Anathem" is massive also -- 900-plus pages -- with a steep initial learning curve, but worth the effort all the same.

Fiction that expertly ranges from social satire to adventure yarn to lucid explications of concepts such as configuration space is rare indeed. If Indiana Jones turned quantum physicist and took over Jostein Gaarder's bestselling novel-cum-philosophy-primer "Sophie's World," well, that might come close.

The world of "Anathem" is an alternate version of our own, a not unfamiliar science-fiction premise. Here, though, the disparities assume a pointed significance as the story unfolds.

The narrator, Fraa Erasmas, belongs to a "math," a community of scholars and thinkers who live like monks, sequestered from the distractions and corruption of the "Saecular" world.

Yet as much as the maths resemble monastic orders (down to their ascetic way of life and many rituals), the members, or "avout," mostly don't believe in God. Instead, they are committed to "theorics," a collection of disciplines "[r]oughly equivalent to mathematics, logic, science, and philosophy on Earth." (That last quote is from the glossary at the back of "Anathem," very handy when reading the first few chapters of the book.)

Forbidden within the maths are most forms of advanced technology; as the novel gradually discloses, this taboo is the result of an ancient agreement with Saecular authorities, intended to slow technological change to a rate at which it can be, as one character puts it, "understood, managed, controlled." A few maths, called Millenarians, have gone so far in embracing this ethos of exclusion that they only open their gates once every thousand years and are otherwise cut off from the world.