Visual Arts: Erotic fantasy from the heart of the stones

What goes round comes round, says Tom Lubbock. And in sculpture, what was first put forward in jest soon became the sensual language of the modernists

MODERN art repeats itself, the first time as a joke, the second time in deadly earnest or it often seems that way. So many significant developments begin in incredulous humour, with someone saying: and I'll tell you the next thing they'll do, these artists, if they go on like this, they'll ... Then, later, the preposterous fantasy comes true.

Abstraction and action-painting were both anticipated (by cartoonists and others) years before the real things arrived. And in 1931, four decades ahead of Richard Long, the sculptor Jacob Epstein, said: "There is so much talk now of material that I can foresee, as a logical conclusion, an exhibition of stones."

But the talk that Epstein was reacting to, he'd been involved with himself. "Truth to materials" was a big slogan of English modernist sculpture - meaning, if a sculpture is made of stone, it should respect this fact and not attempt to simulate flesh. "Direct carving" was another: sculptors should be physically involved with their material, and not (as Rodin had done) make models in clay and get craftsmen to remake them in marble. It was a movement that emphasised its hands-on honesty, and Epstein was one of its pioneers. He had himself affirmed sculpture's identity with its natural materials, declaring: "I want to carve mountains.

Carving Mountains is the name of the exhibition now showing at Kettle's Yard in Cambridge, devoted to English stone sculpture from 1907-37. It includes work from the first generation of carvers, Epstein, Gaudier-Brzeska and Eric Gill, and from the second, Henry Moore, Barbara Hepworth and her two husbands, John Skeaping and Ben Nicholson.

The sculptures here aren't themselves mountainous. They're small works, some of them tiny. But the survey is very well chosen, and conveys the sheer adventure of getting the chisel out and getting stuck in - taking as one's example not the classical tradition with its straining limbs and heaving muscles, but more primitive and archaic artefacts, self-contained and static figures whose elemental shapes didn't disguise the blocks of stone they were cut from.

A certain purity was the hallmark of this work, and the propaganda encourages us to see if as a back-to-basics and rather high-minded enterprise. But looking at Epstein's Female Figure in flenite or Gaudier's The Imp, we should recognise too what curious creations they often are - as indeed they appeared to contemporaries (and not only those who thought them hideous). Carving stones so that they look like stones bring its own particular psychological bias.

The sculptors don't abandon the human body, but the bodies they carve tend to be stout and sturdy, or to coalesce into compact, streamlined, almost shrink-wrapped forms. Surface detail is simplified. There are no extruding limbs. These are ideal bodies, and the ideal they pursue, the thing they really want to be, is a beautiful lump - not just back to basics, but back to the embryo, back to the egg. The Female Figure is a paradoxical creature. Its belly is pregnant, but its head is clearly foetal. The Imp, meanwhile, is part baby, part phallus.

Purism coexists here with eroticism, and of a very practical kind. In terms of the opposition of "carving-good, modelling bad" the works swing both ways. As forms, they're tense, solid and resistant. But as surfaces, the sensation they project is of a hand holding, smoothing, rounding, moulding them. They ask to be handled, to have fingers and palms run all over them (of course that isn't allowed). It would be a bit crude to call them sex-toys, but their touchy-feely incitements are very strong.

This is reflected in the subject matter. Formal compactness favours certain kinds of behaviour - principally hugging, clustering, coupling and bonding. In a group piece like Frank Dobson's The Man-Child (authentic ethnic title!), figures and limbs are hardly separate from each other, just emerging from unity or merging into it. In fact, the main drama of these works is the pull of individual bodies against the mothering pressure of an embracing form. And though figures sometimes wrestle or copulate (at least they do in Eric Gill's work), the most common and the most natural subject here is mothering itself, the primal union of mother and baby.

Breast fixation is often a literal description. In Gaudier's Caritas, and later in Moore's Suckling Infant, mothers and children are indissolubly joined. One block of stone, one organism. The Moore takes a fully infantile point of view, reducing the mother simply to a pair of breasts. And both images are at first very hard to work out, which is just as it should be - not being able to tell the difference between things is the idea.

It wasn't all primal stuff. What's interesting about the work of Dobson, for instance, is how he can use these devices to do something more socialised and urban. His female Torso (armless, headless and stopping above the knee) is his masterpiece, I think, and it's an extraordinary formal construction, full of surprises at every turn. As you move around it, the body continually swells and tautens in ways you least expect. At the same time, it's like a shop window mannequin, with a slim "flapper" bust, breaking into a pair of mighty thighs.

But Epstein's joke-prediction of "an exhibition of stones" was already coming half-true when he made it, in the work of Moore and Hepworth. It wasn't the mountain that was the model, but the pebble on the beach. Hepworth's Mother and Child of 1934 shows how far this can go. A small stone lodges in the lap of a larger one, both barely humanoid. There's something peculiar about carving stones so that they perfectly assume the smooth knobbliness of a sea-washed pebble - making something look as though it's actually been found. You do almost believe that this pair of mother and baby stones had just been spotted, picked up and playfully put together.

And that's something the work wants you to feel. It pays tribute to the natural world, and the excellent shapes it turns up. It declares that art is best when it simulates nature, because nature really is more artistic than art - it just needs a kind of invisible helping hand, sometimes, to bring it out. Moore and Skeaping take this even further, in little carvings that seem to hope to pass virtually incognito among their natural brothers and sisters on the shore.

Strange to say, but this school of sculpture, remote though it appears from Dadaist outrages, was its own way an anti-art movement. For what could art make that nature couldn't make better? What could be more true to materials that the materials unmodified?

And the move into geometrical abstraction in the later Thirties looks like a last minute gesture of recuperation, before the artists had simply to resign their chisels and polishers in favour of uninterrupted beach- combing. Spheres, cylinders, right angles: here were forms that water and weather couldn't do. As a poet said: "I think that I shall never see/a poem lovely as a tree," but you don't want to put yourself out of business completely. It was left to a later generation, Richard Long and other raw nature workers, to realise that that could be good artistic business, too.

Carving Mountains , Kettle's Yard, Cambridge until april 26. Admission free. Then at De la Warr Pavilion, Bexhill-on-Sea. May 2 to June 28.