When we're young we know we'll age, but we can't bring ourselves to believe it. We practise a form of wilful ignorance, an unconscious self-protecting burial of the head in the sand for fear that it might otherwise take the long view and see discouraging sights.
When I got my first driving licence it was valid until 2022. I remember looking at that date and thinking it unthinkable.
In our solipsism we also struggle to believe in the past because we were not there to experience it. The world comes into existence only when we are born, so every birth is the creation of a new Eden. And our first impressions of the world form the template against which every later world is judged.
I am currently tutoring a 16-year-old who wants to study English at university with a view to becoming unemployable. My tutoring consists of little more than giving him the freedom of my bookshelves.
He has just started on Catcher in the Rye. When I read it for the first time at about his age I found it funny. I remember laughing with Holden Caulfield at the old man who pretended he wasn't picking his nose but "the finger was right on up there".
But when I read it again at 30, which was the age at which Salinger wrote it, I found it less convincing. It seemed to me then that the 16-year-old narrator was actually the 30-year-old author in linguistic short trousers.
Holden Caulfield thought thoughts that youths didn't think, or at least that I hadn't thought at 16.
None of which, of course, I said to the 16-year-old who's now reading it. All you can do with the young and literature is lead them to the well. They have to work out how to drink for themselves.
Even as I was typing that last paragraph I heard a car outside and there at the wheel of a black Honda Civic was my god-daughter. Having known her all her life it still astonishes me to see her driving.
In the 16 years since she was born just about everything has happened that is going to be significant in her life, but during that same span of time nothing of any significance has happened to me and indeed very little that I can even remember. Time, as Einstein observed, is relative. It is also subjective.
When I met my god-daughter's father more than 40 years ago he was a handsome beast who bubbled with irreverence and heterosexual zest. Now he's gap-toothed, grey-haired and slump gutted, but rightly proud of his daughter who came late and splendidly into his life.
She emerged from the car in the way that only 16-year-old dancers can and gave me a hug and a card and a bag in that order. The hug put me in mind of the one decent poem that Leigh Hunt wrote, which goes by the title Jenny Kissed Me and which I haven't got room for here, but if you're in need of a fillip I'd advise you to look it up now.
Hug done, I read the card and opened the bag. Well now, my 16-year-old god-daughter, whom I have known since she was a bawling scrap of barely sensate flesh, had given me a bottle of single-malt scotch whisky that was older than she was.
"You know how to warm an ageing heart," I said and she skipped back into the car and drove off towards a world that thrummed with hope and possibility while I withdrew into my shell and added her gift to the others I'd received.
There were four of them and I am quietly proud of the fact that all four were drink.