Two weeks ago my wife gave birth to a little boy. We have been groping our way through a world of sleeplessness and dirty nappies ever since.
Ranulph, or Rafe for short, is a quiet and biddable baby, but sometimes the only way to get him to sleep is to hold him. Now is one of those times; so I am typing this with my right forefinger, while cradling him in my increasingly numb left arm. The clicking of the keys seems to soothe him.
He is too young to smile, or even to focus properly, but looking at his pink little face and tiny fingers, it's impossible not to wonder what sort of world we have brought him into.
Rafe is very much a child of the 21st Century, but since the number of centenarians doubles every decade, he must have a good chance of living to see the 22nd Century.
A re-enactment of a WWII battle , but what relevance for future generations?
I was born in 1944, a couple of weeks after my parents' street was bombed by a German rocket, so my birth and his last years may well be a century-and-a-half apart. By then, World War II will be as distant as the Charge of the Light Brigade is from us.
The changes I have seen in my time are nothing to those Rafe will see.
Europe is more closely linked today than any group of nations in history.
Real success, as America, Canada, Britain and Australia have all found, comes from drawing in new people, new ideas, new traditions
Another war like the one which nearly killed my mother and my unborn self is unthinkable.
The great empires are all gone. Even the United States, once unassailably rich and powerful, is visibly declining.
The wealthy white nations have had to shift aside a little. India and China are on the rise.
But real success, as America, Canada, Britain and Australia have all found, comes from drawing in new people, new ideas, new traditions.
Japan, France and Germany, which have tried to stay the same, have suffered accordingly.
Change has been fatal to the old elites. Britain, so class-conscious for much of my life, so white, so male-dominated, is changing utterly.
The fact that David Cameron, the new British Conservative leader, had been to Eton, the school of so many Tory leaders, was regarded as his biggest drawback.
A brighter future?
In 1900, the main question that worried thinking people in Britain was the condition of the poor. A century later, 70% of people own their own homes.
Reading, theatre-going, listening to classical music - all the things that gloomy traditionalists assumed over the years would die out - are at an all-time high.
But now all this theorising has upset little Rafe. He has gone bright red and is starting to yell. I will have to pause while I prepare a feed for him, then hold the bottle in one hand while I carry on typing. A journalist's son must learn to share his father's attention.
When I was the age he is now, the United Nations Charter was being drafted. It was based on the notion that a few countries, the five permanent members of the Security Council, should direct the affairs of the world.
The way the UN tackles global issues could change
Disagreements over the 2003 invasion of Iraq highlighted the growing irrelevance of that approach.
And any future US president will think carefully before attacking another country without full international backing, and no future British prime minister will dream of lending his or her support without it.
But what if our ignorant selfishness causes some catastrophic ecological disaster? What if our grotesque population explosion leads to some terrible new Black Death?
Could Rafe's world, instead of growing richer and better governed, become more savage?
Quite possibly. But all we can really do is extrapolate from our past. And anyone who has had a front-row seat at the main events of the past four decades must be cautiously hopeful.
Reasons for optimism
During my lifetime, you were more likely to be right by being optimistic than pessimistic. For most of it, there seemed a good chance that the nuclear powers would blow themselves and everyone else into oblivion. It has not happened - so far.
There were many more wars. Only a handful of states were democratic. Latin America, Africa and Asia were mostly run by despots, often propped up by the US and its allies.
The Kremlin, geriatric but brutal, kept its boot on half of Europe. The Vietnam War pitted the most ferocious modern weapons against peasant societies.
We have the Iraq war now, but it is not on the same scale.
The current clash of cultures is likely to fade
The supposed clash of cultures between Islam and the West is no such thing. Fundamentalism, Christian as well as Muslim, is merely a response to the suddenness of change, and it will fade.
One major theme of the past 40 years has been the fading of unacceptable power.
Anyone who has seen the crumbling of the Soviet system and the peaceful ending of apartheid must expect that some way will be found for Israelis and Palestinians to live in peace.
If Rafe is lucky, his world will be one where common humanity means much more than the waving of our little coloured flags. And his elderly father's time will seem as unimaginable as Dickensian England.
But now, if I am any judge, he needs a nappy change. Nothing, I assure you, puts a quicker end to high-flown contemplation than having a two-week-old baby.
Do you agree with John Simpson's views? Send us your comments.