THROUGHOUT OUR Western socities, we all know what we mean by the '60s. They were clearly a challenge to our civilization for which it is hard to find any sensible comparison. The very earth shook, from Berkeley to Bonn. Much of the uneasiness of our day-to-day lives, as well as the shifty improvisations of our democracies, are still dictated by what happened in the '60s. Yet we are unable to fix them.

It ought to be clear without saying that when I talk of the '60s, I do not mean every individual who lived through them. When we speak of the '20s, we do not mean that every woman was a flapper; or of the '50s, that every man wore a gray flannel suit. By labeling the decades -- and it is surprising how they are genuine and not arbitrary divisions -- we mean their distinctive tone. That distinctive tone is set by those among the young who must personally challenge the rules and attitudes of their elders.

I am at the moment -- not at all unwillingly -- revisiting the '60s. A granddaughter whom I have never seen before has just traveled across the Atlantic -- flying alone at the age of 8 from Marseilles, with a change of airlines in Paris, to Washington on her first flight ever. I will be forgiven for thinking that her solo flight across the Atlantic is a saga that rivals that of Amelia Earhart. I fully expected her to arrive in the headgear of an early aviator.

This long-awaited encounter is part of a reencounter during the past month with her father. My son is now 31. He and I had not met for 13 years. A commonplace story, it may seem -- a broken marriage and family, and only an added complication: that 3,000 miles separated the father from his children. (No seeing the children on weekends.) But there is something more interesting to the tale than that.

My son was born in 1950, part of the postwar baby boom. (That was not why he was conceived, I hasten to reassure him. His mother and I did not say: "There is a baby boom, we must join it.") But it did mean that he found himself bang in the middle of the generation which hit us in the '60s. It also meant that I was thrust, like it or not, bang into the middle of them.

Only this need be said of the long drawn-out tussle which he and I then had: Both of us were articulate, neither of us backed down. He stood his ground as a hippie -- which is more than many hippies could or would do under challenge -- I stood my ground as a square. The battle may sometimes have been fierce, but an articulate battle can have at least this worth: Even if it does not immediately yield understanding, the conflict can (if hard-fought) find the ground of a strong mutual respect.

From respect for my son, even where I disagreed with him, I found a respect for the '60s, even where I disagreed with them. He was not then a "plastic hippie," a contemptuous phrase he often used then. He believed in what he preached, trying strenuously to live his ideals, and he still to an unusual extent does so. He poses to me in the most personal and direct way the question: What were the '60s?

What in the '60s was true, what in terms was meretricious? What that was plastic in them have our societies unfortunately kept, what of value in them do our societies seem as unfortunately to have discarded? To this last question, I have no doubt of my answer: There was an idealism in the '60s -- at the heart of them, in the best of them -- which our societies seem to have misplaced.

The first thing to say about the '60s is that they revealed a change in what we mean by generations. We should put aside the too simple idea of a generation gap. Insofar as that was the cause of the conflict in the '60s -- and that was not very far -- it was hardly different from the conflicts of previous generations. What the '60s revealed -- by an unexpected reaction to them -- is that generations now change faster. By about 1972, the younger siblings of the young of the '60s began to be visible. They disdained or rejected how their elder brothers and sisters had behaved and they did so with almost more primness and severity than their parents. "There are no longer simply generation gaps," I remember one American professor saying about 1974, when he had taken a new freshman class, "there are now sibling generation gaps."

The rebellion of the '60s was perhaps the last great confrontation of generations in the old sense -- such a rebellion began in America about 1911, the rebellion to which John Reed of "Reds" belonged -- when the earth on which the elders stood seemed to shake, and a chasm to open between them and their children. But then something unusual happened to the '60s, and I do not think we have yet grasped its significance.

Just when the normal sifting of values between the two generations was about to take place after the confrontation -- some old values kept, others modified, some new values accepted -- along came the younger siblings who were not their parents but also were not their elder brothers and sisters. They did not so much change the battleground -- which is to be expected -- as flatten all contours that had defined it.

To some extent these younger siblings were like jackals, picking over the carcasses of the stricken on both sides. They took what suited their convenience, indifferently, from their parents and from the '60s. We call them the '70s. We also call them the "Me Decade." They would not battle, and they did not; they would not experiment, and they did not. As the '60s had turned on, so the '70s turned in; and their parents, gratful for any peace, turned off.

The '70s took what was convenient to them from the clothes, the hair, the drugs, the music, the sex and the slogans of the '60s, and as they turned them to their profit, there was nothing left to fight about. What had been the banners of the '60s became the bumper stickers of the '70s. They adopted what was convenient in the '60s -- and discarded what was strenuous in them.

For in the best of them, the ideals of the '60s were strenuous. They took one of the most needed, unsettling, revolutionary impulses in our civilization -- the belief that only by changing how one personally lives can one hope to change the oppressiveness of our institutions -- and made it live, throb and challenge, until it seemed to the elders that barely any familiar ground was left that had not been mined.

In print at the time, as well as in words to my son, I hurled back the challenge, more than some elders who abjectly surrendered. I would not wear their clothes; I would not sing, or even pretend to like, their music; I would not -- I had addictions of my own -- take their drugs; I would not seek to weaken or destroy every institution merely because it was not perfect; I would not trample on the heritage of my civilization for a promise of heaven on earth so vague.

Perhaps above all, I would not tolerate new and slippery meanings being given to old and unslippery words, to justify one's own sloppiness. All of this I felt; all of it I said; little of it do I now regret.

To anyone who lived in the '60s, and fought its battles on one side or the other, no year was more terrible than 1968. The feeling that society itself was collapsing seemed to be fearfully reflected in the personal lives that were collapsing all around me. There was very little civility left, in either public or private discourse. It was hard to believe that there would be any survivors.

Yet I never doubted that the challenge was as vital as the need for some to resist it. Some truth lurked at the heart of it which was caught in a word -- "Liberation" -- whose meaning I think our societies have barely begun yet to explore. This is where I have parted company from those who now call themselves neoconservatives, but some of whom to my personal knowledge were by no means very staunch in resisting the '60s at the time.

All of us feel some threat in the example of any life which is lived differently from the way in which we live our own. There is always, for one thing, the suspicion, and so the resentment, that one is missing something. At the back of all our minds -- whether the Roman meeting the barbarian, or the square meeting the hippie -- is the feeling: "He is freer than I am." And so we warn, grave as Cicero, of the risks.

Yet I cannot deny from the evidence of my own eyes and ears that many millions of people are today more free than they had any hope of being 20 years ago. Not only any hope of being, but in fact any ambition of being. Not only blacks and women and homosexuals -- I still will not concede so pleasing a word as "gay" to any one section of people who would rob us of it -- but all kinds of people in their lives.

I find no way of denying that the genuine hippie philosophy was the spearhead -- often flung in wrong directions -- of a major assault on many of the constrictions on personal lives and relationships in our societies. I will still, and still do, argue with what in that philosophy seems to me misleading, even deceptive. But until my son is shown to be less decent, less truthful, less caring, less hard-working in his chosen tasks, less skilled in the employment of his talents, less striving, less humurous than I or anyone else, I will believe that the true hippies are brave and worthy.

What the '70s took from the '60s was ease: license and self-cosseting in their own lives. The '60s produced communes -- that age-old aspiration of the common children of God; the '70s produced singles bars. The '60s experimented with drugs and sex at least with the intent of moral purpose; the '70s used the new freedom of sex and drugs as if they were an alternative to batting in the Little League.

I have three children, each born four years apart. The position of the middle child, in this context, has an interst of its own. During the '60s she had a normal admiration for her elder brother, combined with a frequently expressed impatience with the risks he took and the trouble he caused. ("Why is it always Simon who gets arrested in the demonstrations against the war?") So Charlotte grew up, extremely attached to both him and her younger sister, in the middle of them.

There came one crucial and, in a way, unexpected moment a few years ago, when she said to me, with all her concentration of feeling: "I feel closer to Simon's attitudes and ambitions than to Emma's." Four years younger than the one, four years older than the other, fond of all her family and not modeling her life on her brother's, it cannot have been easy for her to say. Yet she was arraying herself, in the context in which she spoke, with the '60s.

It seems to me one of the most important things that parents have now to realize: that the normal sibling rivalries and adjustments, in families over all the centuries, are now reinforced by the "sibling generation gap." Partly because of the influence of the mass media, from records to television, the old familial battle of elders and children is changed. The children of one decade, in one family, may now span what used to take a century.

Two of my children have now presented me with granddaughtrs. Charlotte presented me with Hannah only on Christmas Eve last year; I can scarely predict anything of her beyond the arrival of the next tooth. But it is possible to look on my 8-year-old granddaughter, Jadi, with some measure of rational, if not objective, judgment. Before one criticizes the effort to live a hippie life by its original ideals and standards too briskly, I would like to be shown another girl of her age who has been better raised to reflect the values I most treasure as livelily as she expresses those of her father.

So life ones on. The survivors, in mind and heart and soul, are not always, thank God, those one expects.