THANK THE NONEXISTENT GODS that Joshua Ferris has a sense of humor.

In his new novel, To Rise Again at a Decent Hour, Ferris introduces us to Paul O'Rourke—despairing dentist, superstitious Red Sox fan, needy atheist. Every day, Paul peers into the human mouth and finds an abyss containing multitudes. Foremost among them, a reminder that everybody dies: "Open cavities are the eye stones of skulls, and lone molars stand erect as tombstones."

When someone begins impersonating Paul on the internet—first creating a website for his dental practice, then creating a Twitter account to post missives about an obscure religious sect—Paul is drawn into an interrogation of his own identity, and his deep, boundless need to belong to a tribe, any tribe at all. (Except for the Yankees-fan tribe. That's out.)

It'd all be a bit much—the relentless fixation on the impermanence of human existence, the preoccupation with religious and secular belonging, the long stretches of Bible talk—if Paul weren't so comical in his befuddled hopelessness. Paul finds "the interlocking N and Y" of the Yankees' logo "a symbol so offensive only the Nazi swastika compares with it." He has complicated feelings about emoticons: "simplifications of speech, designed by idiots, [that] resulted in hieroglyphics of such compounded complexity that they flew far above my intelligence. Then came the animated ones, the plump yellow emoticons with eyelashes and red tongues suggestively winking at me from the screen, being sexy, making me want to have sex with them."

Ferris casts this poor baffled dentist out, among digital, historical, and religious mysteries far beyond his ken, and then reels him back to solid land, less changed than you might expect. It's a confounding trip for the reader, funny and thought provoking and dry by turns, and it certainly doesn't offer easy answers—but then, any book that promises easy answers is probably lying to you.