ART / Rubble without a cause: James Hall contemplates the cult of the fragment, sermons in stones and the impact of 'challenged' sculpture

When is a ruin a ruin, and when is a ruin rubble? This is a multi-million dollar question, and it has been taxing the world's finest minds for several centuries. The taxonomy of ruins is now so complex that the architectural historian Robert Harbison recently called for a 'careful series of the degrees of ruin like a paint chart or colour wheel'. A ruin chart is exactly what is needed at two shows that have just opened in Leeds.

Respect for ruins is a relatively recent phenomenon. Until the Renaissance, ruins had no intrinsic value. They were rubble. Old structures were just rebuilt, or their materials cannibalised for new structures. Gradually, however, Roman ruins were accorded the status of religious relics. In the Report on Ancient Rome, compiled by a member of Raphael's circle for Pope Leo X, we read: 'The little that remains of the ancient mother of glory and of the Italian name, witness of the divine spirits whose memory even today creates and moves us to virtue . . . should not be altogether wiped out by the depredations of the evil and the ignorant'.

But it is in the 18th century that ruins really come of age. In Italy you have Panini, the first specialist ruin painter, and Piranesi, recorder of the Antiquita Romane; and in England Bentley, with his ruin-strewn illustrations to Gray's 'Elegy'.

In such cases, the archaeologist's sadness at the destruction of past civilisations was tempered by the connoisseur's appreciation of fragments. Edmund Burke, in his Philosophical Enquiry into the Origin of our Ideas of the Sublime and Beautiful, claimed that incompletion is superior to wholeness 'because the imagination is entertained with the promise of something more'. Paradoxically, the cult of the fragment gave cultural cannibalisation a new impetus. It was a licence to loot, to break up. The fixtures and fittings of old structures were dismantled and absorbed into a new building type - the public museum.

The construction of the pounds 5m Henry Moore Institute, which has just opened in Leeds, involved a large element of architectural cannibalisation. The architects, Jeremy Dixon and Edward Jones, have inserted five minimalist 'white cubes' inside a listed but neglected 19th-century building. The front facade is covered in black marble which is castellated near the top to expose five windows. Presiding bathetically over it all, like an old king of the castle, is a lone chimney-pot.

Though it looks like a folly from the outside, the internal gallery spaces are some of the most refined in the country. The remit for the Institute is to show sculpture of all periods and nationalities. Those viewers who wish to take their interest further can go upstairs to an extensive library and archive; and those who wish to visit the adjacent Leeds City Art Gallery can cross the elegant connecting bridge.

The first exhibition is entitled 'Romanesque Stone Sculpture From Medieval England'. But it could equally have been called 'Redeeming Rubble'. Most of the exhibits have never been shown before - either because they were in bad condition and had been put in store, or because they are recent discoveries. After emergency conservation work, they have been declared fit for public consumption.

The first 'sculptures' that we see are 14 sandstone fragments from the Augustinian priory of St Mary at Guisborough. First built in the 12th century, it was demolished after the Dissolution of the Monasteries in 1535, and used as a quarry by the locals. Most of the bits shown here were retrieved from undergrowth in 1987. Mounted directly on to the white gallery wall in a long wavy line, they look like sandstone notes on an invisible stave. Some are legible. Others are not. Nos 4 to 6 are 'Fragments of Three Heads'. In No 4 (30 x 22 x 29.5cm) we can make out the right third of a robustly rudimentary head. There are a schematic eye and ear, regular quaffs of curly hair, and the beginnings of a beard. It's more difficult to wax anthropomorphic about No 6 (16.5 x 21.5 x 22cm). According to the catalogue, it shows 'the lower right part of a life-size beardless male head with wavy strands of hair ending just below the partly visible ear; the carving quickly fades around the side of the head'. To appreciate all this, you need to be a fragment fetishist of the first order.

The centre-piece of the exhibition is 13 standing figures from the west front of York Minster. Because of erosion, they were removed from the facade in the 1960s and placed in store. Now supported by metal armatures, they have been evenly distributed around the main, double-height gallery. But they are mutilated shadows of their former selves. Only three have passable heads, only three have passable robes, and only one has a passable pair of hands. The guide tells us that they are Biblical males, but it is often virtually impossible to make out the books and scrolls they are purported to carry.

As Romanesque Sculpture, created in the aftermath of the Norman Conquest, they fall dismally short. We know this because seven standing figures from St Mary's Abbey, York are reproduced in the catalogue. They are in much better shape. The robes are rucked with deep, rippling folds. All the figures stand with eyes, and bibles, front. There can be no doubt that this was the advance guard of the Church Militant.

Under normal circumstances, it would be hard to understand why the Henry Moore Institute had chosen to start with sculpture that is so, er, 'challenged'. If the purpose is to encourage conservation, we need to have some inkling of the splendid 'before' as well as the sad 'after'. But I suspect the Institute is not overly concerned about the failure of these works to succeed as Romanesque Sculpture. For their ruinous state tallows them to approximate what Henry Moore took to be Modern Art.

A case for what we might term neo-Romanesque Art could be constructed along the following lines: Henry Moore is a typical modern artist. He collected weathered stones and driftwood. He believed there was a naked, primal energy in accidental but natural forms. A related impulse lead Moore to say that Michelangelo's unfinished 'Slaves' in Florence represented a more powerful phase of his art than the earlier and more finished 'Slaves' in the Louvre. In Moore's own sculpture, the human body is often fragmented. Heads and limbs are elided, or reduced to knobs. Seen in this light, Romanesque Sculpture can be said to improve with age. It sheds superficialities (the vulgar, brightly painted surfaces, and the easy-to-read iconographic accessories).

What remains is the essential, natural core. That is why it is silly of critics to describe these sculptures as enervated extras from a Norman Night of the Living Dead. It sounds good in theory, but in practice these fragments left me cold. They fail to entertain the imagination with the promise of something more.

If you are looking for ruins with attitude, rather than mere rubble, then you should make the trip to Kirkstall Abbey on the outskirts of Leeds. Built between 1152 and 1182 from local gritstone, it is a unique example of early Cistercian architecture. Roofs, windows and furnishings were removed in 1539, but because of Kirkstall's isolation, the stone was not quarried, and the walls stayed intact. Architecture doesn't come much more spartan or monumental. Here you sense that ornament is crime, and you hardly miss the luxuries that were lost.

Since the 18th century, the Abbey has been a major tourist attraction. Romantic poets and writers such as Walpole, Gray and Southey, and artists including Girtin, Cotman and Turner, all savoured Kirkstall's stern sublimities. The latest visitor is the German minimalist sculptor Ulrich Ruckriem, who has been commissioned to make a site-specific work by the Henry Moore Sculpture Trust. Ruckriem is to the manor born. Before becoming an artist, he trained as a stone-mason and worked on the restoration of Cologne Cathedral.

Ruckriem's repertoire is limited, but he comes into his own here. His practice is to display geometrical blocks of stone, their surfaces patterned by a range of vertical and horizontal splits. Here he has placed six tall triangular lumps of green dolomite stone down the side of the nave. Ruckriem calls them his 'Egyptians'. A sort of seat has been carved out of one half of each block, too narrow to sit on. It is as though the sculptures cannot decide whether they want to stand up or sit down. This seems like an appropriate response to the ruined Abbey: it leaves the viewer in two minds, uncertain whether to feel uplifted or overwhelmed.

(Photograph omitted)