Howard Jacobson: Be grateful for the amnesia that allows us to forget what we were like when we were young

Depressed, thin skinned, unstable. Would we want to be on the receiving end of ourselves?

The young, like the poor, are always with us. One year they sneak around in crepe-soled shoes, the next they put bones through their noses, and now they're hiding their faces away like neophytes to a monastic order. Same kids, different paraphernalia. Leave them alone. You wouldn't order a visiting party of cannibals or Capuchin monks off a shopping precinct, so why pick on hoodies?

The young, like the poor, are always with us. One year they sneak around in crepe-soled shoes, the next they put bones through their noses, and now they're hiding their faces away like neophytes to a monastic order. Same kids, different paraphernalia. Leave them alone. You wouldn't order a visiting party of cannibals or Capuchin monks off a shopping precinct, so why pick on hoodies?

That's the humane position. My position is not inhumane exactly, just more finely nuanced. The young, like the poor, are always with us. But whereas the poor can't help it, the young can. They can't suddenly turn old, I grant you, but they don't have to draw attention to themselves. The shoes, the bones, the hoods, are not intrinsic to youth. They are a decision. As it happens, a wrong decision. So kindly leave the property.

I will come clean. I am frightened by the young. They alarm me, whatever they are wearing. Last week I went to address some of the country's brightest sixth-formers at a private school in north London. The mother of one of the boys had bought me to perform this very service in last year's Independent charity auction.

That alone made me tense. I have never been bought before. Someone buys you and you suddenly feel it's you that has the bone through your nose. Would they open my mouth and check the condition of my teeth? Would they get matron to strip me and stand me on the school scales?

In the event, I was well treated. The boys were literary geniuses, not outlandish in their dress, almost certainly not concealing weapons about their persons, and had good manners. The only ruffian among them was me. But under their influence even I remembered I wasn't there to smash the place up or use bad language. Nonetheless, they were unnerving. The young clever can be just as menacing as the young armed. A sharp tongue can do a lot of damage. And there is a certain quiet haughtiness the well-educated young possess which rattles you. What are the little bastards thinking?

In this way they are as terrifying in their self-possession as snakes or spiders. You don't know what they are going to do next. You don't understand the physics of their movements. And that's the thing with hoodies, too. You can't imagine their raison d'être; therefore you do not know which part of yourself to protect first.

And don't tell me it's all in our minds. Of course it's all in our minds. That's the part of us they like to mess with, whether they're wearing hoods or blazers. The argument that they won't do you any harm in actuality is fallacious: they have already done you harm. Is anticipation of harm not harm? Do people my age not die of apprehension?

It would help, we are told, if we remembered that we too were young once. No it wouldn't. In my view, our having been young once is precisely the problem. We forget because we need to forget. Call it self-preserving amnesia. Because if we remembered what we were like we would be even more frightened than we are. Depressed, wayward, bellicose, thin skinned, unstable, inflammatory, willing to do anything to gain the approval of our peers, and even more to win the admiration of the opposite sex - who would want to be on the receiving end of ourselves?

Happy slapping, is it called? - punching someone in the face while your friends film it on their mobiles? Anyone do that to me and I will kill them. Never mind shooting pellets at their feet; I will tear their hearts out. And yet I can well imagine, had some seductive girl recruited me, and had I been considerably more plucky than I was, taking up happy slapping myself aged 16.

No one who knows me believes this. They reckon I was too well brought up. They may be right. It helps, if you are not going to be a happy slapper, not to be the child of happy slappers. But behind the well-brought-up boy, I know what lurked. And I see it, waiting to pounce in all its chaotic unhappiness, whenever a kid in a hood approaches me.

And this, despite what I know of actual kids in hoods. I spent a day observing hoodies in Manchester a few years ago, on an assignment for this paper. They had taken over a square outside the new Marks & Spencer. Maybe they were even wearing Marks & Spencer hoods. What struck me about them most was their democracy in the matter of gender, the quietness not to say the introversion of their demeanour, and the custom they had adopted, as though to make fun of those of us who spend our evenings at the Groucho, of elaborately greeting one another with a kiss on each cheek - mmah! mmah! - without ever making fleshly contact.

Whether they were as sweet and gentle-natured as they looked I cannot say, but in that incarnation at least, they were less menacing than an old lady with a shopping trolley in a hurry.

Sweet and gentle-natured, though, is a proper description of the Hell's Angels who regularly invaded a shop I once helped to run in Cornwall. Every bank holiday they would roar up, de-rev their bikes, swarm in like the Mongol hordes - smoke still issuing from their helmets, their death's head rings flashing fire - and barge their way to the bottom of the shop where we could not see, and in truth did not want to see, what they were up to.

When they re-emerged they would always be carrying scented candles or hand-made bowls of pot-pourri which, shyly, they would ask us to gift-wrap for them, with a card saying "To My Nana".

So why do they still strike the fear of God in me? Because it's myself I dread. The hoodlum I might easily have been, so deranging did I find the condition of being young.