It's a question that's been nagging at my mind for a long time now, and maybe at the minds of not a few of my generation, the baby-boomers: what is the real meaning of the Sixties?
Switch off at once, if you like. Turn the page. A billion words have already been spouted on the subject, principally by the baby-boomers themselves, by those who lived through the whirlwind years of social change and social turmoil - yeah Dad, you were in Paris in May 1968, you've told me already.
I'm only returning to it because to me, for all the books that have been churned out and TV documentaries made, for all the reminiscences of ageing rock stars and the reconstructions of social historians, no-one seems to have got it. No-one seems to have captured the true significance of those years when the children of the men who had fought in the Second World War came to their maturity, and changed the world - or so they thought.
The drama and visibility of the age, of course, remain enormous - the demos, the sit-ins, the love-ins, the be-ins - and some outlines are clear. There was a huge rise in personal freedom: to dress differently, to drop out from conventional society, to pursue alternative careers and lives, to take drugs, and perhaps most of all, to have unlimited sex. Accompanying the new freedoms was a corresponding decline in authority, at all levels: of the government, of the upper classes, of the priest, of the teacher, of the father, of the husband; and, depending on your point of view, these changes marked a wonderful breath of fresh air, or the point when the rot set in. Maybe the truth lies somewhere in between. But it doesn't get to the heart of it, for me.
Another way of looking at the Sixties, the political way, is to see it as a brief age of hope, when a whole class of people believed that the world could be changed for the better, not only through politics, but through music, through drugs, even love. There have been other such ages with their believers, such as the Renaissance with its humanist scholars, and the French Revolution with its radical bourgeois lawyers; in the Sixties the believers, uniquely, were the young. That's undoubtedly a distinguishing characteristic. But for me it doesn't get to the essence either.
I've been drawn more and more to the idea, not of what changed in the Sixties, but of what was entirely taken for granted - of what was normal. The more I consider it, the more it seems to me that Sixties normality was a very remarkable normality indeed. I think of my own experience. I was born into a lower-middle-class family on Merseyside in 1947 and went to university in 1965. Growing up, I never remotely went hungry. I never went unshod. I never drank dirty water. I was never threatened by poor sanitation. I was threatened by disease hardly at all, but when I was ill the free state health service was superlative. I was given a classical education, to university level, entirely paid for by the state. I had no fear of violence, private or political. I had no fear of arbitrary arrest, no fear of imprisonment, torture or execution - and I could say or write openly whatever I wanted (within the bounds of the libel laws). I had no fear of conscription into a war which would kill or maim me, or of the necessity to take sides in a deadly struggle; instead, I had showered upon me all the burgeoning freedoms listed above.
Just how exceptional this normality really was becomes clear if we look to history; or, in more sinister fashion, look to the future. Down the centuries, even in the 20th century, the daily experience of the overwhelming majority of people has been vastly different: hunger, disease, poverty, violence, have been - still are - their lot. To grow up in the rich West in the years after 1945 was to partake of a privileged existence unique in history in its extent. There has not been its like before. And there may not be again.
I write about the environment and so am regularly presented with assessments of environmental threats to the planet, principally from climate change. The general public mood about global warming and its possible consequences could be characterised as mild interest, perhaps tinged with concern; but few people who pay close attention to the issue can be optimistic about the future of the earth, and the best-informedjudges I know take a very dark view indeed.
And now, of course, it is becoming clear that our society, with its liberal values bequeathed to us by the 18th century Enlightenment, is mortally threatened in other ways. Let us think what was once unthinkable, but is not now: let us imagine, some time in the years to come, the explosion by a terrorist group, of whatever background, of a nuclear weapon in Manhattan. What happens the next day? What happens, not only in the US, but in other states that wish to avoid this fate? The immediate sanctioning of the torture of any suspect atom bombers seems merely the beginning; liberal democratic society would be tipping over the edge.
None of this may come to pass, of course, but whatever shape the future takes, I do not believe it will ever offer the combination of plenty, security, peace, health and freedom enjoyed by the children of the Sixties, when the worst that could happen to you was that your girlfriend left you, or maybe you died of a drug overdose. You look back at it all and wonder what it means? I'll tell you what it means, my generation, my brothers and sisters the baby-boomers: we had the golden years, and they will never come again.
Tragedy isn't confined to the human species. At the weekend it struck at Britain's most celebrated bird's nest of 2005, which belonged to a pair of bee-eaters, the most colourful things on two wings in all of Europe (chestnut, aquamarine and primrose-yellow).
They've only bred in Britain three times in the last 50 years, and this pair had chosen to nest on the River Wye at Herefordshire, where last week 3,000 people turned up to have a look - until foxes found the nest.
There may be many tough breaks in a bee-eater's life, but having your kids eaten by foxes is surely one of the toughest.