LAST NIGHT IN PARADISE: Sex and Morals at the Century’s End.<i> By Katie Roiphe</i> .<i> Little, Brown: 196 pp., $21.95</i>

According to Katie Roiphe, Americans have become wimps. We drink mineral water and eat arugula; we fasten our seat belts and obsess about sexual harassment; we’re fretful safety freaks, timid old maids. Most--and worst--of all, we’ve abandoned romantic love and erotic passion, transforming ourselves into emotional and sexual eunuchs. “It’s as if ‘health’ and ‘safety’ have become the highest goals, the most elevated and sought-after forms of human experience,” Roiphe charges. In the battle between Thanatos and Eros--a battle that, Roiphe seems to believe, began circa 1981 with the discovery of AIDS--Thanatos is the decisive victor, and we have all become spinsters of the soul.

What’s wrong with this picture? Not quite everything, but more than enough to make “Last Night in Paradise” both annoying and, ultimately, far from illuminating. The problem with this confused book is not that it is so contradictory--nothing wrong with that--but that Roiphe lacks the intellectual ability to illuminate the complex cultural shifts that she attempts to chart.

Much of “Last Night” is an extended complaint against the stultifying repressiveness that, Roiphe insists, pervades American culture. But wait: She also complains repeatedly about what she sees as the meaningless permissiveness of the “new tolerance” that she insists has triumphed (she is especially disturbed by a Harper’s Bazaar headline that asked, “Adultery: Can Cheating Help a Marriage?”). She yearns for the sexual freedom of the ‘60s with its “Edenic glow”; she pines for the sexual repressiveness of the 19th century with its “baroque grandeur.” She is a fierce defender of mindless hedonism (in one bizarre chapter, Roiphe lauds the idea of unsafe sex with an HIV-positive partner), but she’s nevertheless disappointed that anything goes.

Is it possible for a person, or a culture, to encompass such opposites? Sure. But does Roiphe attempt to explain where these contradictions come from, what happens when they clash and how they might resolve themselves? Nope. “Last Night” is like an extended psychoanalytic session--full of wildly conflicting desires, romantic fantasies, projections and over-generalizations--without the analyst.

In her previous book, “The Morning After,” published in 1993, Roiphe, a graduate of Harvard and Princeton, castigated campus feminists for their purported obsession with date rape and sexual harassment. Although filled with a weirdly Ayn Rand-like belief in the triumph of the will, “The Morning After” did raise some valuable questions about the wisdom of focusing on sexual violence as a political or psychological strategy for women’s liberation. It was also, alas, notable for its utter lack of sympathy for women who are in fact victims, or indeed for any woman whose life might be far different from, and more difficult than, Roiphe’s.

Roiphe’s problems in “Last Night,” which focuses largely on the cultural fallout of the AIDS crisis, begin with her ignorance about the origins of the sexual revolution. She is no fan of the left or of the ‘60s counterculture; accordingly, she largely ignores them (not to mention the civil rights, black power and feminist movements). She is, therefore, left with the puzzling notion that the sexual revolution somehow sprang up among white middle-class suburbanites (key texts are “Open Marriage” and John Updike’s “Couples”).

For Roiphe, who is 28, the sexual revolution of the ‘60s had nothing to do with a desire to create a more erotic and more egalitarian society. Instead, Roiphe focuses on “bikinis from France, and the Pill, and nudity in movies, and honest and open marriages, and no-fault divorces” and then notes that “paradise” mysteriously failed to materialize. She is like the theatergoer who takes her seat during the second act and then loudly whispers to everyone around her that the plot makes no sense.

Mistakenly, Roiphe believes that the sexual revolution consisted simply of “having sex with as many people as you could.” She is oblivious to the fact that the sexual revolution--at least for many women--was less about mindless promiscuity than about finding newer, truer, less sexist and more ecstatic ways of being sexual. It was about the experience, not just the numbers; about creating something, not just getting lucky.

Her analysis of the complex relationship between sexual repression and the advent of AIDS is equally reductionist. On the one hand, AIDS has ruined the party (Roiphe begins the book by revealing that one of her sisters is HIV-positive); on the other, she is aware that anxieties about AIDS have also given “form and meaning to our free-floating doubts.” The fear of AIDS, she writes, has “became a kind of blank canvas against which we could project our own . . . cultural needs.”

What has produced those needs, those doubts, those anxieties? Many things, of course, including the radical destabilization of the nuclear family, profound changes in the roles of women (and blacks), the increasing polarization of wealth and the emergence of gay liberation. And there are psychic fears to consider: of losing power, of losing love--of losing. AIDS might also be a metaphor--as Susan Sontag wrote about cancer--”for our shallow attitude toward death . . . for our inability to construct [a] . . . society that properly regulates consumption, and for our justified fears of the increasingly violent course of history.”

Unfortunately, Roiphe is interested in virtually none of this. She gives an occasional brief nod to a few ideas about social instability, the “craziness” of the ‘60s and emotional risk, but her answers to the questions posed by the metaphor of AIDS are, for the most part, astonishingly incomplete. For Roiphe, the anxieties that AIDS epitomizes are essentially about fear of sexual freedom itself. This may be true as far as it goes, but it doesn’t go very far.

And Roiphe fails to offer compelling explanations as to why we fear sex or, for that matter, freedom. She specifically rejects the seemingly incontrovertible idea that “there are dark and uncontrollable forces contained in the sexual impulse itself” (and rather oddly misidentifies this belief as “puritanical”). Nor does she seem aware that the struggle against freedom--political, sexual, psychic--is strong, ancient and transnational, not newly minted or peculiarly American.

Roiphe is in the odd position, then, of being a cultural critic who makes very few cultural connections. She also talks to very few people (the book contains a surprisingly small number of primary interviews), although she speaks for a cast of millions, indeed, for our entire, wildly cacophonous nation. “Last Night” is littered with confident pronouncements about “us”--as in “if we find poetry in anything, it’s safety,” “we are not supposed to be dark continents to each other anymore” and “nothing we do matters.” Roiphe believes, evidently, that she is the world. After a while even the most patient reader may snap, “Girlfriend, speak for yourself!”

Except that she doesn’t want to. In fact, “Last Night” may be, first and foremost, the cri de coeur of a young, privileged woman who is finding out the hard way that she is not the center of anything and that the world will not automatically endow her every act with a sense of gravitas. In the book’s most revealing anecdote, Roiphe recounts how she once spent the night “with a man whom I wasn’t really supposed to be seeing” and was mightily disappointed when, as she left his apartment the next morning, the “bald doorman . . . barely glanced up” from the sports pages “to register my presence” despite her rumpled state. Amazingly, the crowds on the street also ignore her: “And it came to me . . . that no one cared.”

The lessons Roiphe draws from this are all about the dreadful “general permissiveness” into which we’ve descended--about the distressing “ease with which we can now slip in and out of intimacy” and the consequently unbearable lightness of (her) being. In flight from the “depressing futility” of this world, Roiphe harks back to another time. It is the time of “Anna Karenina” with its “high romance” and rigid social mores, and Roiphe mourns the fact that current sexual relationships have lost “the moral and social meaning” they had for Tolstoy. She shirks the knowledge that--as an adult, as a modern woman and as a free human being--she must create those meanings for herself.

Roiphe views AIDS as a kind of biblical curse that has been visited upon her sex-soaked but eros-deprived generation. It may be, though, that it is her own inability to re-envision the world--and to risk radically challenging it--that is to blame for the absence of passion and “sense of pointlessness” that she decries. At one point, she describes what she sometimes sees as her life choices: She could “go to strange cities, do lots of drugs . . . drink until I can’t remember what happened the night before” or, alternately, “marry the first lawyer I meet [and] push a stroller down Columbus Avenue.” She criticizes the right-wing “abstinence movement” because “it isn’t a radical rethinking of the sexual revolution,” but neither, of course, is this book. Saddest of all is her admission: “One of the harder things to understand about the sexual revolution for those of us who missed it was the hopefulness attached to the changes in the culture.”

“All power to the imagination!” French radicals scrawled on the walls of Paris in 1968. It is not only AIDS that has deprived Roiphe of power and freedom but the limits of her own imagination, and that, too, is a kind of caution, a kind of cowardice and a kind of curse.