Last Saturday, my son and his friends, celebrating the end of the Junior Cert exam, headed off to a rock concert.
"Who's up next?" I asked. "Dylan" was the answer. Dylan. Not the Red Hot Chilli Peppers. Nor the Arctic Monkeys. Nor Blink 182. But the Jokerman himself.
I couldn't believe it, bit my lip and pondered those famous lines: "Come mothers and fathers throughout the land/And don't criticise what you can't understand/Your sons and your daughters are beyond your command."
Forty years ago last month, I had sat in the Adelphi cinema, a whole year before my own Inter Cert, to listen to Dylan, then in Ireland for the first time. He sang Positively Fourth Street with the amps turned up loud and delivered entire songs with his back turned on the audience. Some walked out. I went home elated on the last bus: and when I played Maggie's Farm, my father looked up from his Irish Times and said "what on earth is all that noise?"
The point about liking Dylan was that nobody other than true believers could fathom him. "Something is happening, but ya don't know what it is/Do ya, mister Jones?" And his own followers kept splitting into rival factions - folkies, electric heads, country buffs. Because of his constant changes, there never could be an official Dylan style. He was the Last Modernist, who would struggle but never triumph, and in the end struggle in order not to triumph.
My generation - an odious phrase but widely used - had its own music, whose glory was that its secret codes were unbreakable by older people. They had contempt for Dylan's voice, often compared to the howl of an animal whose foot was trapped in barbed wire. And we reciprocated with a fierce contempt for the crooning too-decipherable stars of the previous decades: Sinatra, Crosby, Clooney, Boone.
These people were straights. And nothing could be more anti-aphrodisiac than the styles of the recent past.
Even within the rock camp, the split was often the first item on any agenda. Softies liked the Beatles; beasties went for the Rolling Stones.
If you did admit to enjoying the Beatles, you had to decide between John or Paul, Revolver or Sergeant Pepper. In those days, to isolate something was to enjoy it - keeping the music mysterious and unavailable to others.
Then came the first dispossession. A priest clad in a Clancy brothers sweater arrived one day with a guitar at the start of a folk Mass. He began singing a revised version of Blowing in the Wind - "The answer, my friend, is living in all men/The answer is living in all men."
We all felt terrible about this plundering - as badly as the poet WB Yeats must have felt on hearing the awful news that thousands of boy scouts in serried ranks had recited The Lake Isle of Inisfree under the baton of Baden-Powell on Salisbury Plain.
The second dispossession came much later, when rock classics of the 1960s provided the soundtrack for TV ads. The generation that had set its face against capitalist consumerism now watched as everything from processed peas to clean electricity was sold to the tunes of Simon and Garfunkel, the Beach Boys and Dusty Springfield. Bob, at least, had the grace to refuse to release any of his songs for such misuse - though he did appear in a strange lingerie ad, for obscure reasons of his own. And he tried as best he could to defend his own classics by rejigging them, almost beyond recognition, in strange new arrangements.
Is this the third dispossession, when our very own children take trains to listen to the great man in Nowlan Park?
Today's teenagers appear to have no problem in enjoying the songs their fathers loved. In fact, they can even enjoy the songs their grandfathers loved: Sinatra, Tony Bennett, the lot. And because pop/rock is old enough to have multi-generational history, these kids are set fair to become its profoundest historians.
They're right to be open, of course. What made Dylan the genius he was back in the 1960s was his openness to the entire range of American music, from blues to country, from rock to gospel. Like all great artists, he was original enough to go back to origins, both humble and arrogant enough to believe that a whole culture might speak through him.
Which is all very well, if you're a genius, able to put new electronic instruments to strange, unforeseen uses on old songs and paradigms.
But is there a danger that most of today's teenagers may in time grow baffled and demoralised by the confusing range of choices available to them, in everything from music to food, from academic courses to careers?
One reason for the cult of French theorists on American campuses has been the promise of thinkers like Foucault or Derrida to link up all the disparate forms of knowledge; and to provide over-arching philosophies which give some coherence to a potentially baffling array of college courses. Perhaps Dylan has done something similar in the world of popular music. His Self-Portrait album showed him as early as 1970 to be the first synthesiser of its rich varieties.
Today's teenagers seem to be following him in this and, by that very process, learning how to be his contemporaries. All of which proves that Bob really has mastered the art of staying forever young.