Serenata Terpsichore, heroine of Lionel Shriver’s fourteenth novel, The Motion of the Body Through Space, is a self-described loner. Growing up in eight different states, changing schools every couple of years, young Serenata learned to be wary of attachments. As an adult, she has tended “to mislay companions out of sheer absentmindedness, like gloves dropped in the street.” Now, at age sixty, she is an avowed misanthrope who “would have thrived on a desert island in the company of fish.”

Holding herself resolutely above the crowd, she eschews such “lemming-like behavior” as attending a football game, rock concert, or church service. She shuns all trends, including fitness crazes, popular expressions like bucket list, and anything that smacks of political correctness. Remington, her more outgoing husband, finds her lack of connection to others chilling. “You’ve no idea what community means,” he chides her.

Remington is the exception to Serenata’s self-imposed isolation. For the past thirty-two years, she has given herself utterly to their relationship, which is buoyed by a playful repartee meant to evoke William Powell and Myrna Loy. Serenata has come to think of her marriage in sports terms, as a team. But it is a team of two. “They didn’t need other people enough,” we are told, “not friends, not relatives, and not, alas, their own kids. They’d been too satisfied with each other’s company, which read to outsiders as self-satisfaction, and their contentment came across as exclusionary.”

At age sixty-four, Remington is forced to retire from his longtime job as a civil engineer in the Albany department of transportation. After he and Serenata move to his hometown of Hudson, New York, he casts about for something to fill his abruptly empty schedule, something that will also help him channel his rage over being retired and soothe his bruised self-esteem. One day he announces his plan to enter a marathon, to be held that spring in Saratoga.

Serenata is shocked, since she has never seen her husband run even around the block. She is also horrified. She herself has been a lifelong, compulsive exerciser, clicking off ten-mile runs and hundred-mile bike rides before they were fashionable. But she sees exercise as a private matter, not something to be shared with thousands of strangers. For her, physical fitness is a question of personal responsibility, like keeping your car in good running order, not something you should expect a medal for.

She also finds Remington’s timing cruel, since her arthritic knees, worn out from years of hard use, have recently forced her to give up running herself. Now, as he begins his training, logging what to her are ludicrously short distances of which he is overly proud, she watches with a mixture of condescension and resentment. When he manages to finish the marathon, she is relieved – until he announces his intention to enter a long-distance triathlon called the MettleMan.

For the next fourteen months, Remington gives himself over to his new obsession. He is hoping for his wife’s support and even admiration, but she can’t see the merit in the venture. “What you want from me is patently unavailable,” she tells him. “You’re asking me to completely relinquish my independent judgment – to relinquish myself.” The grueling training takes him away from her for hours at a time, and she feels abandoned. Worse, he joins a triathlon club. Serenata is dismayed when club members take to invading her house, drinking her wine and expecting her to cook for them. In return they treat her with disdain, as a nonentity. So much for her and Remington’s team of two. Their playful banter slips into sniping, and she begins to fear for their marriage.

Her concern isn’t eased on meeting the club’s Svengali, Bambi Buffer, a professional trainer in her late thirties with “the kind of figure used to sell gym memberships.” Unlike Serenata, Bambi believes in the power of community: “I’ve seen it a million-bazillion times,” she exhorts Remington. “Harness the energy of other athletes believing in you, and rooting for you, and helping to bring out your best self, your true self, your uber self – the God inside every damn one of us.” Beguiled by Bambi, he starts spending more of his waking hours with his trainer than with his wife.

As the brutal training drags on, Serenata accuses him of narcissism, of trying to sculpt his body to perfection. To her the whole enterprise is driven by a manic self-involvement. And there is an element of selfishness in Remington’s behavior. He spends money they can’t afford on a high-end treadmill, a $1,200 monthly retainer for Bambi, and a $10,000 titanium bicycle. Although Serenata is a successful voice-over artist, they struggle on her freelance income and his reduced pension.

The extreme MettleMan regimen also has Serenata fearing for her husband’s safety. But even after a chronic injury and a string of alarming accidents, he refuses to quit. She feels that the man she fell in love with has been kidnapped. As the clock ticks down toward the starting gun, she wonders, will they be able to save their marriage and restore their comfortable community of two?

Besides the story of a marriage, an examination of community versus individualism, and a critique of the physical fitness industry, The Motion of the Body Through Space is a meditation on aging. Serenata admits, “Facing all those decades of decline – well, the future seems sort of horrible. Some days I walk around in a state of apprehension, start to finish – wondering what disease is lurking around the corner, and fretting about what I’m supposed to be doing with the tiny amount of time left before it hits.” It’s not death she fears so much as the long, slow descent to the grave. By the end of the book both she and Remington have been humbled by their failing bodies. Will they be able to accept their physical diminution with grace, and even a measure of gratitude? It’s a question for all of us.

Another writer might have been content to leave these themes in the background, informing the action but not taking center stage. But Shriver brings them to the fore time and again, as characters examine and reexamine them in dialogue and internal monologues. As a result, The Motion of the Body Through Space, like other novels of ideas, can feel didactic and repetitive, bloodless rather than dramatic. Also, Remington’s obsession with the MettleMan seems a narrow lens through which to view a marriage: After more than three decades together, shouldn’t he and Sereneta have more interesting things to argue about?

In fact, neither of the main characters is very likable. The reader is apparently meant to agree with Serenata that Remington’s obsession has turned him into an unbearable narcissist. Yet she herself is described (often in her own words) as competitive, jealous, judgmental, insensitive, rigid, cold, critical, territorial, spiteful, bitter, unkind, and antisocial. “She was not a nice person,” we are told, “and had no desire to be one.” Remington and Tommy, Serenata’s one female friend, take gentle exception to her professed lack of human warmth. Are they just being loyal, or are they able to see something in her that we can’t? Maybe the point is that we are all guilty of these failings at times, but Serenata certainly seems to go out of her way to be disagreeable, almost as if she (and the author) were challenging us to love her despite herself. In any event, it’s hard not to see her poor regard for others as a kind of narcissism more corrosive than any behind her husband’s athletic adventures.

At a time of ferocious backlash against efforts toward racial and social justice, do we really want to risk coming down on the side of the bullies and the bigots?

Our empathy for Serenata and Remington is further tested by various regressive and even racist ideas that the author puts in their minds and mouths. White people, they believe, are generally regarded as “unfathomably evil.” Fear of a black man on a deserted street is reasonable. And the author appears to share their point of view. Remington is forced out of his job by Lucinda Okonkwo, an incompetent, angry black woman. She and a black man are the only two characters who consistently speak in substandard English. Serenata’s voice-over career collapses because the foreign accents that are her specialty are now considered a form of cultural appropriation. Gender-neutral restrooms, preferred pronouns, workshops on sexual harassment and racial awareness, and the concept of white privilege are also held up to ridicule.

Shriver is well known as a literary provocateur. Her other novels have taken on controversial subjects, such as school shootings (the international bestseller We Need to Talk About Kevin) and the American healthcare system (So Much for That, a finalist for the 2010 National Book Award). In interviews and in her other writings, such as her column in the conservative British magazine The Spectator (an American citizen, she divides her time between London and New York), she has often expressed anti-progressive sentiments. In The Motion of the Body Through Space she is goading us to examine our own prejudices. And the ideas, however politically incorrect, aren’t discriminatory in themselves, she argues. As Remington says of Lucinda, his nemesis, “I dislike her personally. As an individual. Is that possible anymore? Is it legal to harbor animosity toward a specific person who just happens to belong to a ‘marginalized community’?”

Well, yes, but. Remington’s question, like the ironic quotation marks around that last phrase, serves to minimize longstanding, legitimate concerns. At a time of ferocious backlash against efforts toward racial and social justice, do we really want to risk coming down on the side of the bullies and the bigots? Isn’t it a particularly virulent form of narcissism that insists on a smug, self-serving contrarianism even to the detriment of real struggles by real people? Lionel Shriver and her characters succeed in provoking, but not in persuading.