Jan Vermeer's View of Delft, painted in about 1660, is his most disconcerting meditation on the visible world. It is a superlatively realistic painting of the town where he was born and died, a place suspended between sky and water, its gates sealing from our eyes a secret world where roofs are bathed in golden light. Vermeer's Delft is somewhere you'd want to live.
This is the place that is celebrated in the exhibition Vermeer and the Delft School, an attempt to set Vermeer alongside other artists, such as Pieter de Hooch and Carel Fabritius, who worked in the town in the 17th century. The show, which opens here next month, is currently pulling in record crowds at New York's Metropolitan Museum, the biggest hit there since the last Vermeer exhibition.
Vermeer's View of Delft is, however, a vulnerable illusion. It's a slender presence - a thin band of brick between the clouds and that deep, still harbour. Above, a raincloud menaces the light on the rooftops. Below, the shadows of the walls in the water have a terrible solidity - a second, deathly world glimpsed in the water. Mortality threatens this town. Deliberately or not, Vermeer is reminding us of a disaster that ripped the town apart and claimed the life of his greatest rival.
Proust thought this a good painting to die in front of. In 1921, the year before his death, the novelist made a pilgrimage from his sick-bed to see Vermeer's masterpiece, on a rare loan from the Mauritshuis in The Hague. Proust staggered into the Jeu de Paume gallery in Paris, and while he did not actually keel over before the View of Delft, he had one of his characters do just that. Proust went home and immediately wrote the scene in Remembrance of Things Past in which the writer Bergotte sees the dryness of his own art revealed by the richness of Vermeer's: "A new attack struck him, he rolled from the settee to the floor, where all the visitors and warders ran to him. He was dead."
But what is the source of the anxiety that pervades Vermeer's painting?
Six or seven years before Vermeer produced his paean to Delft, another of the city's artists, Egbert van der Poel, painted a very different scene. This View of Delft depicts the town on the morning of Monday October 12, 1654, the day Delft's magazine, which contained around 90,000lb of gunpowder, exploded. The blast took place at 10.30am and was so powerful it vaporised surrounding houses and their inhabitants. Estimates of the death toll range from 100 to 1,000; one-third of the town was destroyed - an extraordinary challenge to this God-fearing culture.
One thing the Dutch were able to do, however, was bear witness. Artists who found themselves on the scene treated it with the same explicitness as a photo-journalist would today. Van der Poel painted the disaster at least 12 times, and DanielVosmaer returned to the subject time and again. This Delft - painted from the north - is the obverse of Vermeer's.
Where everything in Vermeer's masterpiece is poised in an enchanted moment of stillness, in paintings of the explosion the perfect world has shattered. The mullioned windows, drinking horns, lobsters on silver platters, cavaliers holding glasses to the light - all those intimate, precious moments we love in Dutch art - are gone in an instant. The Dutch interior is turned inside out. Houses have no roofs, their walls are pierced, they are open to the elements. Where Vermeer's View of Delft, painted from the south, has a warm architectural density, there's a void - the site of the magazine that disappeared leaving just a pool of water. Trees are blasted into splinters, people crawl out of a canal and are helped by shocked bystanders. You can believe 1,000 died as you look at charred wood, a bleeding face, two men carrying away a basket of rubble or perhaps human remains.
In Delft today, 350 years later, it's easy to find the physical imprint of this catastrophe. The old heart of the city still has its waterways, neat canal-side houses and little bridges. It's still dominated by the two churches, the Nieuwe Kerk and the Oude Kerk. Delft porcelain is still made there; people still queue for the first herring of the spring. It's all very cosy, until you walk to the north of the Nieuwe Kerk; here - near what is now known as the Horsemarket - is open, structureless space, a nasty car park, a poorly tended bit of park. The area around the explosion remains a gap, a deficiency.
In the town museum there's a painting of the explosion, next to a picture of the same site in 1665, when it had been turned into a bustling horsemarket. By putting the two scenes side by side the museum asserts that Delft swiftly got over its tragedy. Look, here is the resilience of the Dutch, finding good use even for a bombsite.
It's certainly true that in Delft in the years after 1654 a very distinctive art of the domestic appeared. Vermeer's paintings belong to this period of reconstruction, and his vision of Delft is emphatic about the uneventfulness of life here. In the late 1650s Delft was reinvented in art as a place where nothing happens. Vermeer's Little Street (c1658) was executed just a few years after part of the town had been blown to bits. This painting of a Delft canalside house, with a glimpse into its peaceful courtyard, rebuilds a world of solidity, reliability, that will be there when you wake up tomorrow. The art of Delft in its great age does not simply represent this haven of seductive calm but insists upon it. Before the explosion, Delft's artists mostly painted the town from the north, spotlighting the two fine church towers; Vermeer's View of Delft shows, instead, the undamaged side.
Vermeer had a personal reason to be conscious of the explosion as a defining event: it killed the one local who might have eclipsed him. Carel Fabritius - a pupil of Rembrandt's - was ranked by contemporaries alongside Vermeer. On the evidence of the surviving handful of paintings by Fabritius, few would deny that he was Rembrandt's most talented pupil - a follower with more panache, individuality and understanding of his master's work than the rest of his fellow students put together. Fabritius's Self-portrait, painted in the year he died, takes Rembrandt's example seriously yet makes it his own. Fabritius depicts himself as a precociously romantic figure, framed against a brooding sky, in armour to do battle with his demons. Like Rembrandt, Fabritius stands outside the sociable Dutch mainstream, seems drawn to lonely, melancholic moments. He paints isolated creatures - a goldfinch on its perch, and, in his own View of Delft, a man sitting in a reverie as he tends his stall selling musical instruments, which none of the practical people of Delft seems interested in buying. It's no surprise Fabritius was a favourite of Van Gogh.
The romantic Fabritius was to have a fate more absurd and shocking than he could ever have anticipated. On the morning of October 12 he was in his studio on the Doelenstraat, close to the gunpowder magazine, at work on a portrait of the verger of the Oude Kerk. When the magazine exploded, the house collapsed on top of both men. The verger was killed instantly, but Fabritius lay trapped for hours before being dug out. He was carried to the Oude Gasthuis hospital, where he died.
This was the century in which John Milton prayed for strength to "justify the ways of God to men". Daniel Defoe, in A Journal of the Plague Year (1722), his historical novel set in the plague-infested London of 1665, has his narrator attempt to make sense of the suffering around him as the workings of Providence. A 17th-century Dutch poem similarly tries to justify the death of Fabritius. God's excuse, the poet suggests, is Vermeer: Fabritius's fiery death made it possible for Vermeer to rise like a phoenix from his ashes. But the poet didn't know the half of it. In 1864 a fire in the Boijmans museum in Rotterdam, 10km from Delft, destroyed the bulk of Fabritius's surviving work.
The 19th-century French critic Théophile Thoré, who single-handedly made Vermeer a modern icon, was also transfixed by the doomed Fabritius. He figured him as the missing link between the genius of Rembrandt and that of Vermeer. It could not be a coincidence that Fabritius (1622-1654) and Vermeer (1632-1675) both worked in Delft. Surely Fabritius must have taught Vermeer. Where else did the provincially educated Vermeer learn the optical trickery that has led art historians to speculate that he used a camera obscura? Rembrandt's students were interested in optics - the peepshow preserved in the National Gallery is by another Rembrandt student, Samuel van Hoogstraten. Fabritius, too, was an optical enthusiast, celebrated for his eye-fooling perspectives; his View of Delft with the musical-instrument seller has a distorted perspective that suggests that it was painted for a peepshow.
There's no proof that Vermeer even knew Fabritius. But he must have admired him because he owned several of Fabritius's paintings. You can imagine him comparing his own work with that of Delft's lost genius. No wonder Vermeer's Delft is haunted, a city whose survival is not certain, because nothing is.
• Vermeer and the Delft School is at the National Gallery, London WC2 (020-7747 2885) from June 20 to September 16. Vermeer's View of Delft is in the Mauritshuis, in The Hague.
