On television, on billboards, in poetry, at dinner parties and even on the Tube - sex is everywhere

The most memorable scene in Federico Fellini's La Dolce Vita was provided by blonde, buxom Anita Ekberg splashing about in Rome's Trevi fountain. In its spontaneous and joyous exhibitionism, Ekberg's water frolicking captured the optimistic excesses not only of Italy but of the 1960s postwar boom. For life to be sweet, Fellini seemed to say, extravagance must reign.

Thirty years on, extravagance is suspect - yet balance, Aristotle's golden mean, remains inadequately understood, or even sought.

A new collection of essays from Demos valiantly tries to resuscitate the classical Aristotelian concept. Different writers examine different areas of our existence - from marriage (see Penny Mansfield's piece) to genetic manipulation (by the NS's own Caroline Daniel). To succeed in one area to the exclusion of others, the authors warn, is not conducive to happiness.

Yet in highlighting the dangers of excess the Demos collection overlooks the one aspect of modern life where it has become acceptable to forgo any form of restraint: sex.

Our culture does not readily forgive promiscuity (at least, not among gays or women); but it does promote it. Newspaper articles, television programmes, contemporary plays, advertisements - all urge adults, and impressionable children, to overcome inhibitions, overlook propriety and go for it.

Our society can't get enough of sex. Our collective addiction is out of control. We talk about it and think about it (yes, I admit it - I've been quoted as saying that, far from being a good Catholic girl who never thought about sex, I thought about it 9,000 times a day) non-stop: how could it be otherwise, when what was once taboo is now discussed at dinner parties and openly displayed in Tube station clinches? How could we escape its clutches, when subliminal and overt messages target us from displays in Boots and Wonderbra billboards, EastEnders plotlines and how-to books?

Money may no longer be regarded as the sure-fire path to happiness; work is no longer considered the passport to security; sex, however, remains the solution to every problem. The conspiracy is perpetrated by endless manuals and relationship fixers, lonely hearts columns and dating agencies. Feeling blue? Have sex! Feeling old? Have more sex!

Not content to treat sex as a cure-all, we also insist on regarding it as fascinating. Where once artists hailed romantic love as their great muse, they now focus on sex, interpreting its every detail as if it might yield profound truths about our psyche and our heritage. In so doing, artists are merely in tune with the rest of society, which now regards this grunting, panting, sweaty spectacle as a subject worthy of analysis and awe. Approaching sex with a sense of reverence rather than of ridicule, we choose to forget that this is a brutish instinct we share with beasts, and treat the wholly natural and purely mechanical exercise as if each and every consummation were a remarkable occurrence.

Elevated to this ludicrous - and false - position, sex tyrannises us. It demands that we sacrifice tradition, moral guidelines and other people's happiness. And it requires rigid conformity: not only has it become unthinkable to build chaste relationships, but pressure mounts on couples for whom sex is not a daily, hair-raising, moan-issuing out-of-body experience. As for those who espouse celibacy, their way of life has become as inconceivable as if, like Simon Stylites, they elected to spend their days on top of a column in the desert.

Why does our culture sanction this obsession? Certainly, in an era rocked by doubts and existential angst, sex, with its promise of pleasure and procreation, seems life-affirming, a triumph of hope over our dismal experience. True, too, in a world where everything is explicable and the one mystery - religion - has been jettisoned, the reasons for sexual attraction remain excitingly unfathomable.

Our excessive preoccupation with sex, though, jeopardises our ability to lead a good life. It risks undermining the values - respect, altruism, loyalty - and the responsibilities that bind us, one to the other, in a healthy society; and it threatens to raise instant gratification above long-term happiness. Convinced that having an orgasm is all, we lose sight of the essential balance between individual pleasure (sexual intercourse) and community welfare (some of the consequences of sexual intercourse - unwed teenage mothers, family break-downs). In our exaggerated attachment to sex, we ignore the restraints that from the beginning of time have kept our needs, rather than our ideals, from dictating our actions.

Lose your balance and, as thinkers from Aristotle to the Demos authors have argued, you will lose your way. In the end, excess, as even Anita Ekberg found, turns the dolce vita sour.