ART / A bricklayer's view of the world: The meticulous detail of Dutch realism often conceals a larger morality. Andrew Graham-Dixon finds finesse not fussiness in paintings by Vermeer and de Hooch at the National Gallery

RUSKIN had a low opinion of Dutch art: 'The patient devotion of besotted lives to delineation of bricks and fogs, cattle and ditchwater.' 'Brief Encounters: Vermeer and de Hooch', the latest in the National Gallery's series of displays bringing together a pair of closely related paintings, proves him right at least about the patient devotion and the bricks. Pieter de Hooch's The Courtyard of a House in Delft of 1658 and Jan Vermeer's Street in Delft of 1658- 60 each feature lots of bricks, very patiently painted. But they also show that paintings of ordinary things need not be ordinary.

A characteristic twentieth-century response to de Hooch's painstaking recreation of the courtyard at the back of a house in Delft might run along the lines of: so what? De Hooch's apparent straightforwardness is apt to look, to modern eyes, suspiciously like banality. What a dull and uneventful scene, after all, the artist has painted: outside, within the small confines of a brick courtyard, a maidservant leads a smiling little girl by the hand; in the hallway of the main house, open both to the courtyard and to the street, another woman stands, with her back to the viewer, looking away. Nothing much, maybe - yet de Hooch's painting of an ordinary scene in an ordinary home contains its own small drama and is imbued, throughout, with a subtly domesticated form of symbolism.

The Courtyard of a House in Delft is a testament to the Dutch seventeenth-century preoccupation with the home as both seat of private virtue and microcosm of the well-run commonwealth. The painting stands at the opposite pole from those other, livelier scenes of drunkenness and affray also common in Dutch art of the time: an image not of the tavern, with its sensual and moral temptations, but of a place where stillness and security are charged with ethical value. Its theme, emphasised by the painter's tight, narrow framing of his image, is enclosure - which is presented, here, as a state of grace.

De Hooch's courtyard is the setting for a gentle conflict between the virtues of domesticity and the forces ranged against them. The stone floor of the passageway has been polished to a dull shine. The foreground is filled by an expanse of brick paving that has also, evidently, recently been swept: in the bottom right-hand corner of the painting, a well-made broom of bound twigs looks as though it has just been set aside. In distinction to this fantastically clean (and fanatically carefully painted) expanse of floor, the rest of the courtyard seems only precariously ordered, threatened - albeit in a modest way - by the unruly incursions of nature.

Plants sprouting from a strip of earth that runs along the right side of de Hooch's courtyard have begun to creep over the edge of the border; a knot of branches and foliage has begun to spill down from the ramshackle bower under which the maidservant and the little girl stand; while above the archway over the passage, a stone tablet bearing a moralising inscription that preaches the virtues of the retired life has been half obscured by the tendrils of a creeping vine. The child might herself be meant to represent a potentially unruly being, who needs to be led along the path of righteousness. De Hooch's art always seems freighted with such forms of allegorical intent: in his world, people and things are almost invariably carriers of meaning.

De Hooch's painting may be taken as a visual summary of the whole Dutch Calvinist mythology of cleanliness and domestic order, whose legacy is the uncanny, toy-town pristineness of much of modern urban Holland. That broom, lying innocently to one side, has nevertheless something of the emblem book about it, the aura of a symbol carefully placed - and indeed old Dutch emblem books contain many images of brooms and mops, reminders of the symbolic potency which this household utensil came to acquire in the youth of the Republic.

'Look also to subtle things,' runs the legend accompanying a broom in one such book, 'that seem but slight to lazy eyes, and mop them up with your own hand. The cobweb of the vile spider that hangs and sits in all the senses, where dirt and base matter gather.' Which might seem merely to prefigure the modern cult of hygiene, of whiter-than-white germ-free living, but in Holland 300 years ago housework and its tools were invested with a wide range of civic and political overtones alien to the age of Daz and Flash.

Simon Schama, whose brilliant study of Dutch culture in the Golden Age, The Embarrassment of Riches, is especially revealing on the subject of hygiene and housework, makes some interesting remarks about what he calls 'the militant cleanliness of the Dutch' in the seventeenth century. Commenting on one Dutch admiral's gesture of tacking a broom to the bowsprit of his flagship, Schama comments that 'The brush stood as a heraldic device for the new commonwealth, cleansed of the impurities of the past. To have been slaves was dirty. To be free is to be clean.' The broom was not merely, then, a means to cleanliness, but the symbol of freedom from Spanish rule: of the new, purified Holland of the Republic. In de Hooch's painting, it may even acquire another symbolic dimension. A broom is not unlike an artist's paintbrush, and perhaps de Hooch saw a parallel between his own activity, that of registering the bright, clean world of Dutch domesticity, and that of those to whom the task of maintaining it fell. De Hooch's art is itself a form of housework - the work of understanding the house, in all its significance, and of making it clear.

The safe enclosure of the home becomes an image of the safe enclosure of the state. But the outside world isn't absent from his picture since he offers us a view into that world, through the front door, and even includes a figure contemplating it. This figure (who is probably the mistress of the house and the mother of the child) might seem to prefigure other, later figures seen from behind in painting - common presences in Northern European art, and most famously incarnated in the melancholy Ruckenfiguren of Caspar David Friedrich, who seem to be yearning for contact with other, larger worlds than their own.

But there is nothing melancholy about de Hooch's figure, who seems, rather, proprietorially vigilant. And the view which she confronts is only another image of the private, sealed world which she inhabits: she is placed along a vista delimited, at the near end, by the archway of the passage that she occupies and, at the far end, by its mirror image, the arch over the window of the house opposite.

This visual rhyme is also a closure, suggesting that the world beyond the home is identical to the world within it. To look out is to see, not difference, but sameness; and by opening out his picture de Hooch suggests an entire city of safe havens, a vast organism made up of such healthy, single cells as the one he has happened to paint. Art becomes a form of civic self-assurance.

Vermeer's Street in Delft is a greater painting than de Hooch's, but far harder to write about. Where de Hooch is essentially a moralising painter, an artist for whom images define correct or incorrect social behaviour, Vermeer's ethical credentials have always seemed somewhat suspect. Reticent, forever withholding or obstructing easy reading of his pictures, Vermeer remains a thoroughly enigmatic artist.

He appraises the houses that are his subject in Street in Delft not from the back but from the front, and at a greater distance than de Hooch in his Courtyard. Although Vermeer's picture includes genre-like details - the two children in front of the gabled house to the right, playing knucklebones; the woman sewing in the doorway; the other woman, seen through the open doorway to the right, bending over a tub - their diminished scale robs them of the aura, so strong in the de Hooch, of role models, figures meant in some way to instruct. Their faces, moreover, are left blank. This is possibly the most striking example of where Vermeer's painting differs most fundamentally from de Hooch's: namely in the daring quality of its realism, its intermittent, inconsistent, variable nature.

For de Hooch's somewhat plodding manner, in which every last brick is painted with perfect clarity, Vermeer substitutes a much more painterly and less determinate repertoire of effects that range from the precise to the audaciously generalised. He paints mortar between bricks as a skein of lively, darting brushstrokes, a vivid shorthand; he paints red and green shutters by applying the paint in thicker, more buttery layers (an emphasis on the tactility of paint which is appropriate since he is here, in effect, painting surfaces that have themselves been painted); he translates the cobbled street into a mass of painted wriggles.

Vermeer's illusionistic virtuosity carries with it the knowledge that all illusionism, in painting, is a lie. No other equivalently gifted realist artist has ever presented the real in so many different, competing registers, so variably faithful to fact. To see this even more clearly than in Street in Delft, consult the National Gallery's later Woman Seated at a Virginal. This is a painting which, in its varyingly achieved treatment of different illusionistic surfaces - the faux marbre of the virginal, the painting on the wall behind the young woman, the patterned curtain to one side - seems devoted to a demonstration of the partial correspondence of all painted illusions to the realities they mimic.

To be conscious of this - as Vermeer evidently is, too, in Street in Delft, although there he parades it less overtly - is to be profoundly conscious of the gap between art and its subjects. It is to know that the world cannot be replicated in paint, only reinvented. And maybe this is what Vermeer's Street in Delft, in the end, is about: the way in which the world withholds itself from the artist-as-observer, the way in which it retains its mystery. The most forceful visual elements of his design, the dark oblongs of closed doors and empty windows that punctuate the surface of the city's houses, are also powerful images of blankness - of interior spaces that cannot be interrogated by the painter, whose art has to deal with surfaces. The blank faces of Vermeer's people seem relevant here too. Where de Hooch moralised privacy, Vermeer was content to respect it: to leave it impenetrable and intact.

See Listings, opposite, for details.

(Photographs omitted)