Visual Arts: Exposed: the dirty old masters

The Ashmolean's exhibition of 17th-century Dutch painting isn't aesthetically the finest work from the period. But it does offer something else. The rude bits.

The Mauritshuis in The Hague is one of the world's great small museums. Its contents are pretty well confined to Golden Age Dutch painting, but its star works are starry. It has Rembrandt's Anatomy Lesson of Dr Tulp, several of Vermeer's works, including the View of Delft, Fabritius's Goldfinch, Paulus Potter's Bull, and - among other things - some of Frans Post's weird Brazilian landscapes, where the artist seems to turning into the Douanier Rousseau.

At present the Mauritshuis is showing the Rembrandt self-portrait exhibition that was in London earlier this year. To make room, some pictures have been taken down - and rather than going into store, they have gone to Oxford, on temporary loan to the Ashmolean Museum, making up a small show called Scenes of Everyday Life.

So, of course, these are not the best pictures in the Mauritshuis. No, they are among the most dispensable. They're the ones you'd probably miss out yourself. The biggest names here are Gerard Dou, Gerard ter Borch, Jan Steen, Gabriel Metsu, Nicolaes Maes. It's by no means their finest work. And if it's visual pleasure you're after, then the Dutch pictures already in the Ashmolean's permanent collection offer more. (For example, it has Ter Borch's extraordinary silhouetted view of man on a horse, seen directly from behind.)

But, actually, even a random choice of Dutch everyday life painting is going to be worth taking in. For one thing, of all European art, it is the most open to the world. It has its norms, but they're porous. It really is like photography, in this respect: odd bits of unpremeditated reality are always getting lodged.

Look at one of the loaned Ter Borchs, for instance, called Unwelcome News. Here, a letter is brought to a soldier, sitting with his girlfriend. Call-up, maybe - and a choice between love and war. Or maybe not (the title, at any rate, isn't the artist's own). And current critical fashion favours uncertainty. Instead of trying to give a definite story and moral to such scenes, we should recognise that they were designed to be open to interpretation. That was the fun of them - a set of ambiguous clues, a kind of caption competition.

OK, but the striking aspect is something else. In this scene, the woman is sitting on the floor. She's sitting on the floor, very casually, half- kneeling/half-sprawled, leaning fondly on the man's knee (he's in a low chair). How often you've seen couples in this posture - watching TV together, say, or at the fag-end of a party. But have you ever seen it in a painting, pre-20th century? It may be meant to indicate particularly loose behaviour. But the point is, Ter Borch has clearly observed it, and put it in. I don't know where there's a parallel.

Or take another bit of casual reality: arse-wiping. Now the dirty-mindedness of other ages is always hard to judge. Rudery is a great cross-cultural mystery. It involves distinctions that are keenly felt but very elusive. Nowadays a newspaper cartoonist (say) might pause before doing an image which featured someone wiping a child's bottom, with a bit of visible shit, and someone else gagging at the bad smell. It wouldn't be out of the question, but it would be quite strong.

On the other hand, pre-Victorian cartoonists, such as Gilray or Cruikshank, wouldn't have hesitated. Nor did some of these Dutch artists.

Jan Miense Molenaer does a vulgar take on the conventional subject, The Five Senses. He pegs all of them on beer-drinking - sound, drunken singing, sight, peering sadly into the empty flagon, and so on - except smell. Normally this is represented by someone sniffing a flower, and for consistency here, it should perhaps be farting, though that might be hard to convey clearly. But instead, he does the incident described above.

And now try to imagine what Vermeer (a picture dealer as well as a painter) might have thought of this subject. Would he have found it jolly, or risque, or foolish, or disgusting? Perhaps the puzzle is really a matter of genre: we don't expect this kind of dirt to appear in respectable oil paint, but in some more graphic medium.

Teasing the Pet, by Frans Van Mieris, is a more ticklish case. It's no rough pub scene, but something much nearer to Vermeer's own line: a scene of bourgeois flirtation, with an eye for lighting and fine fabrics. At the same time, it seems to be deeply rude. A lady sits holding a puppy in her lap, a gentleman is tweaking it, she is demurely pushing his arm away, and he catches the viewer's eye with an expression of what I think is meant to be ribald complicity, as if to say: we both know it's not really a lapdog I'm thinking of, but some other furry thing.

I exaggerate? Well, many Victorian anecdotal painters were inspired by these Dutch domestic episodes. So think how a Victorian artist would and wouldn't have handled the subject. Stroking an animal held by someone else is a recognised if rather yucky form of flirtation - fingers may accidentally brush, there's displaced fondling, but it's fairly innocent stuff. A Victorian painter could happily paint that.

But put the animal specifically in the woman's lap, and (a) the man's hand may get literally too close for modesty (b) the stroked creature itself is likely to acquire metaphorical status. The symbolism arises naturally out of the situation. And a Victorian painter (unless he was extremely innocent) wouldn't be happy with this version.

A 17th-century Dutch painter, apparently, was more than happy. A modern saucy postcard would be, too, though in that case the creature would, of course, be a pussy, with a caption to underline this perhaps. (The Dutch, according to Simon Schama, thought cats were dirty, and didn't pet them.) But the Van Mieris scene is in other ways nothing like such a postcard. Its colours, textures and human gestures are subdued and refined. It has the subtle qualities that would have appealed to a Victorian imitator - all except its central Playboy gag. And that's the alien mystery of it: the unruffled fusion of rudeness and politeness.

Is a similar bit of symbolism at the heart of Jan Steen's Girl Eating Oysters? (She offers one to the viewer.) Oysters were thought to be aphrodisiac, but surely the seafood associations don't stop there. And I hope no one will say that "post-Freudian" attitudes are being inappropriately, anachronistically, introduced. On the contrary, it was only because a huge repertoire of conscious sexual symbolism had been forgotten by educated Europe that Freudian theory - or one part of it - had its opportunity. And again, for all its fishy innuendo, this is a refined painting.

Not an especially good painting. And that's true of most in this show. But for curiosity value, for cultural tourism, it keeps stopping you in your tracks. And it may affect your view of the absent masters, too, even of Vermeer. His holily lit interiors, occupied by women with mysterious inner lives, stand at one end of a continuum of interest in what goes on inside women - and at the other end, the concern is much more literal. Look at Godfried Schalken's Medical Examination. It is a pregnancy test. The doctor is holding a flask, containing a urine sample, up to the light. Look closely, and you can see the test is positive - a tiny little homunculus, symbolising the conceived foetus, floats in the urine. Wow.

`Scenes of Everyday Life: Dutch Genre Paintings from the Mauritshuis', Ashmolean Museum, Oxford (01865 278000) to 9 January. Tue-Sat 10am-5pm, Sun 2-5pm, closed Mondays, admission free