What we see as a blurry paradisaical fog in `Waterlilies' was, through Monet's clouded eyes, an exact representation of reality

A team of scientists in San Diego has identified something called mirror agnosia or "looking-glass syndrome", to explain why some people, staring into a mirror, think that the objects they can see are floating in the mirror's mercurial depths rather than merely being reflections. Patients under inspection would bang their hands against the mirror in trying to reach "inside" it.

The syndrome is generally found in people who have had a stroke, or suffer from migraines, or have damaged the right side of their brain and no longer recognise things located on their left side. (I know, it all sounds as mad as Mike Tyson, but stay with it). Because of the mirror connection, some Californian has called it an "Alice in Wonderland Syndrome". It took only a couple of minutes for someone else to deduce that Lewis Carroll must himself have suffered from it. And next thing you know, The Daily Telegraph is claiming that Alice "was a figment of Carroll's migraine".

I see. So the master of Victorian surrealism wrote the way he did because he had chronic headaches? He invented Jabberwocky, the Frog Footman and the croquet flamingoes because of a disordered, rather than an inspired sensibility? What utter nonsense. But then, coincidentally, I met a neurologist called Russell, who spends his time studying the brain's response to certain stimuli. He said he had no problem with the Carroll-wrote-Alice-because- he-was-barmy syndrome. "I mean," he said, "Look at Monet..."

Russell has published an article in The Lancet that tries to diagnose why Monet painted the way he did. Digging out the magazine, I discovered there's a whole platoon of doctors out there, with names like Ravin and Skaff, devoted to the study of eye disease among Degas, Pissarro et al. They had already established that Monet had developed cataracts late in life, and that what we see, in "Waterlilies", as a blurry paradisaical fog was for him an exact representation of reality; but then, that's what you expect when someone's old and failing (Monet's eyes clouded over in his sixties; he died at 86).

What Russell found out was what Monet's eyesight was like in his prime. He'd had a patient called Monet, a great-grand-nephew of the great man, with a wasting eye condition called myotonic dystrophy, which starts in your middle years, gets worse, and eventually gives you cataracts - and is hereditary, though it jumps generations.

Claude Monet, said Russell, had started life as a pin-sharp draughtsman, but was drawn towards indistinctness, distortion and colour-blending while still in his twenties. Why? Because his eyesight was changing. Just look at the properties of myotonic dystrophy: "Initially, these consist of punctate, iridescent, white and/or multi-coloured opacities, especially in the posterior subcapsular region, sparing the central portion of the lens, progressing to rosette-type cataracts with radiating spokes, and then to reticulation of the lens cortex." That, ladies and gentlemen, is a definition of the inner landscape of Impressionism.

Or is it? I've also been told that El Greco painted his saints with long faces because he suffered from some disabling strabismus. Next they'll say that Joyce wrote Finnegans Wake out of some pun-inducing mental frenzy, and Damien Hirst's cow-slicing aesthetic derives from a zoophobic condition you can cure with antibiotics. I don't believe it's that simple. You can blame genius on all manner of physiological kinks, but you can't account for it all. No amount of learned articles in The Lancet will satisfactorily explain, say, Mr Dale Winton.

Reading the other day about the iniquitous rise of Ms Pauline Hanson, the former barmaid and fish 'n' chip shop owner (and former Liberal) Australian MP who now leads the gibberingly racist "One Nation" party on the simple policy platform that aborigines are a bunch of baby-eating freeloaders who should be denied welfare payments, and should have their faces sawn off, too, while we're at it - it struck me I'd come across her surname rather a lot lately. It and its phonemic variants have taken over the world. There are three juvenile-delinquent Hansons in a band imaginatively called Hanson, at the top of the hit parade with a lyrically challenged song called "Mmm Bop". There's another one called Beck Hansen, presumably a distant cousin, lower down the charts. There's a row going on at the Park Lane Hotel, involving two more Hanson brothers, one a director, the other a shareholder. There's Lord Hanson of the well-known trading group, and, er, Mansun, which is another pop group obviously modelled on Charles Manson, the sadly unfashionable murderer, and Ted Danson, the actor-barman of Cheers fame and er, er, Lanson, that frightfully posh grand marque champagne and Lisa L'Anson, the Radio 1 girl with the velvety voice, and Jennifer Aniston, who was Aristotle Onassis's god-daughter and plays Rachel in Friends and, er, er, er - well, there were a hell of a lot more Hansons the last time I looked, but they seem to have disappeared...

I went to an Oxford gaudy on Friday in my old college, a reunion of three years of early-Seventies undergraduates. Tuxedo and waistcoat settled on gently spreading tum, I pushed open the door of the Junior Common Room and peered through the hot crush of elderly dons, trying to spot my wild 'n' crayzee mates from the days of 28-inch yellow loons embroidered with butterflies. They weren't there. Then I realised they were the dons. It was a weird Night of the Living Dead scenario, scrutinising the features of Richard X or Peter Y and detecting, somewhere in all this expanse of face and jowls, the vestiges of someone I used to know well. Of the quantity and quality of hair on display, the less said, the better. More interesting was how much had changed, how much stayed the same, how we'd turned out. One of us was running a feng shui clinic in Alaska (though why Innuit tribesmen need advice on where to put their furniture is beyond me). Another is Commercial Secretary to Her Majesty's Embassy in Tokyo. A third has just jetted in from LA, where his first movie is in ante-pre-production or some such thing. A fourth answers to the name of Rouge Dragon Pursuivant at the College of Heralds... How grown-up we were, how very Oxford, as we nibbled the college lamb, drank the college claret and nodded at speeches about public subsidy and private enterprise. The guy across the table explained to his neighbours the difference between a hapax legomenon and a hysteron proteron. The son of a former cabinet minister gave me a dead cert for the 3.50 at Newcastle. And when dinner was over, we rushed to the Undercroft bar, bow-ties and gowns a-flying, drank gallons of Bass, played bar football and lampooned each other's pretensions. Remembering the candlelit dinner in hall, one recalls, not an agreeable miasma of success and shared endeavour, but the collective sigh of 300 mid-fortysomethings sharing a vast, collective mid-life crisis.

At last I've discovered the precise location of the Nineties generation gap - the gap that exists between the Baby Boomers, who grew up in the Sixties, and their offspring, who missed the whole Revolution thingy but have struggled to reach some kind of maturity in their early twenties. I realised the exact point of psychic breakdown, when my friend James told me about the devastating young ingenue on whom he is currently pressing his suit. "She's very keen on music," he reported. "Even ancient Seventies music, like Pink Floyd, so we were chatting away about The Dark Side of the Moon. And then I said, `What's your favourite track on Side Two?' And there was this awkward silence, and she looked at me oddly and said, `What's Side Two?' "