Paul O’Rourke is a quintessentially contemporary protagonist – of a certain sort. He’s a dentist, and a good one, with a practice on the Upper East Side of Manhattan and a condo overlooking the Brooklyn Promenade. He’s a Red Sox fan, wrestling with the unexpected letdown of his team having won the 2004 World Series, a victory that, in some essential way, has left him bereft.

“I didn’t want my team to lose,” he notes; “I just didn’t want my team to be the de facto winner…. The days of trembling uncertainty, chronic disappointment, and tested loyalty – true fandom – felt vitally lacking.” As to why this is important, it’s an expression of identity, framing Paul as part of “a cursed and collapsing people,” scorned, neglected, their very purpose one of degradation and of loss.

This posture of rootlessness, of drift, occupies the center of Joshua Ferris’ third novel, “To Rise Again at a Decent Hour,” which Paul narrates with an offhand grace. He is, like so many of us, lost in modernity, surrounded by choices but unable to connect. His relationships are fleeting, overly idealized; they end as soon as they get real. He has no friends, not really, just a trio of women who work for him in the dental office and the patients about whom he cares in the abstract. He detests digital culture, which distances him from a world to which he can’t relate.

“I was already at one remove before the Internet came along,” he argues. “Now I have to spend the time that I’m not doing the thing they’re doing reading about them doing it? Streaming all the clips of them doing it, commenting on how lucky they are to be doing all those things, liking and digging and bookmarking and posting and tweeting all those things and feeling more disconnected than ever?”

Even baseball, to which he devotes such attention, is not, in the end, a panacea, especially since his devotion to the Red Sox is the last legacy of his father, who committed suicide when Paul was a boy.

“Come back, you ghosts,” he beseeches. “The day is hard enough. Don’t leave me alone with the night.”

Ferris has been a Virgil of the disaffected since his first novel, the PEN/Hemingway-winning “Then We Came to the End,” was published in 2007. There, he traced the decline of a Chicago advertising firm, writing in first-person plural to evoke the dehumanizing aspects of the workplace; his follow-up, “The Unnamed” (2010), involves a successful lawyer who begins to walk compulsively as a way to escape, or at least avoid, the desolation at the heart of his own life.

“To Rise Again at a Decent Hour” can be read as a further meditation on a theme, a novel that raises questions about meaning and belonging, even if the only answer is that we will never know. “What’s the point?” Ferris writes in the opening chapter. “In the end, the heart stops, the cells die, the neurons go dark, bacteria consumes the pancreas, flies lay their eggs, beetles chew through tendons and ligaments, the skin turns to cottage cheese, the bones dissolve, and the teeth float away with the tide.”

What he’s on about is flossing – which, he tells us, “prevents periodontal disease and can extend life up to seven years” – but he may as well be discussing existence itself. This is the novel’s peculiar brilliance, to uncover its existential stakes in the most mundane tasks.

Eventually, Paul gets called out, challenged: A shadowy antagonist creates a set of online profiles for him (Facebook, website, Twitter) against his will. Initially, the problem appears to be a legal one, yet here, too, Ferris plays against our expectations, as Paul finds himself reluctantly drawn in. The postings lead him to encounter another group of cursed and collapsing people: the Ulm, a lost tribe not unlike the Chukchi or the Penan, who exist somewhere in the middle ground between extinction and assimilation, and reflect the conflicts of a wilder and more elemental world.

In the case of the Ulm, these tensions are quasi-religious; they have been persecuted because “they believe in nothing but their obligation to doubt God.” As to whether they actually exist, or are merely the product of a stalker’s imagination, this is the conundrum with which Paul must wrestle, made more complicated by his ambivalence about the possibility of connecting at all.

“The difference between ten believers and ten million believers is a categorical one,” a rare book dealer named Sookhart tells him. “We call the one a cult and the other a religion. Personally, I don’t care much for that distinction. But without a certain critical mass, things do sometimes get weird.”

For Paul – and Ferris – weird is where we live now, in a world so divorced from its own essence that it might as well be virtual. In his infatuation with the Ulm, then, Paul finds a way back to himself. Such a move is not always handled smoothly: Much of the last third of the novel involves an enmity between the Ulm and Judaism that Ferris neither completely explains nor justifies. In part, this has to do with the distinction between belief and ritual, but if Ferris means to make a larger point about community, he doesn’t fully pull it off.

In the end, though, it’s a problem that, if not minor, doesn’t derail the book. How do we live in a world where God, where spirit, has forsaken us, if, indeed, it ever existed at all? How do we make meaning out of trivia, out of the detritus of desire? These questions drive both Paul and this curiously provocative novel, which seeks a reconciliation life cannot provide.

“There was the hum of the river,” Ferris writes, “and the island across the river, and the last desultory traffic of the night washing by on the expressway below. I can only suggest the effect it had on me, that is, the feeling that my life, and the city’s, and the world’s every carefree, winsome hour, were perfectly without meaning.”