Just think about it

Inside the cloisters, avouts pursue theoretical physics, mathematics and astronomy; outside, the largely aliterate society gorges itself on movies, junk food and abundant supplies of genetically engineered mood-enhancing drugs, as well as politics, cellphone/Blackberry devices called (delightfully) "jeejahs" and religion. The Saecular world regards the maths -- especially the mysterious Millenarians -- with varying degrees of suspicion, curiosity and awe. (Erasmas, our narrator, is only a garden-variety Decenarian, which means his math holds an open house every 10 years.)

On his acknowledgments page, Stephenson describes "Anathem" as "a fictional framework for exploring ideas that have sprung from the minds of great thinkers of Earth's past and present." At the heart of this exploration is a conflict between two major strands of Western thought that, in recent years, correspond to analytic and continental philosophy. Is philosophy primarily a matter of language and the working out of a consistent structure of reasoning about data that we experience directly, with our senses? Or are there fundamental truths accessible only through philosophy and the highest modes of thought?

Is the number 2, in other words, no more than a conceptual tool, a product of the human mind? Or is the 2 we know merely the shadow of an ideal reality that we perceive through a glass, and darkly? To judge by "Anathem," Stephenson comes down on the side of the latter, which makes him something of a Platonist, a believer in a transcendent reality, and an adherent to a position intellectually out of fashion in the humanities departments of most Western universities.

This may not sound like the stuff of compelling fiction, and the fact that the characters in "Anathem" occasionally engage in Socratic-style dialogues on these (and related) topics might scare some readers off. But that would be a mistake. Stephenson has done something remarkable in this novel, which is to make the resolution of a venerable philosophical debate essential to the unfolding of his story.

Fraa Erasmas and his mathic colleagues are "evoked" (that is, called forth from the math by the Saecular authorities) when their world faces an unprecedented crisis requiring their expertise. One solution may lie in cryptic hints left behind by a beloved, exiled teacher. The avouts' conversations about geometry and quantum states aren't intellectual detours from a perfunctory plot; they are one of the forms the story takes. "Anathem" turns what often seem like airless, abstract debates into matters of life and death. In order to save the world it becomes crucial to determine what the world really is.