Tony Cragg, Scottish National Gallery of Modern Art, Edinburgh

Works by Tony Cragg may adorn many a company atrium, but that doesn't mean he has sold out

Shapeshifter: The viewer struggles to tie down Tony Cragg's Bent of Mind (NATIONAL GALLERIES OF SCOTLAND )

That Tony Cragg's Edinburgh Festival show should be the first for a decade in a major British gallery seems odd.

Cragg is everywhere. Peer into the atrium of any self-respecting City bank or FTSE 100 head office and there will be one of his sculptures, torqued in Kevlar or pitted with dice or glinting richly in burnished steel. As Henry Moore found to his cost, ubiquity breeds contempt: "Turd in the plaza," people would sneer as yet another Mother and Child appeared in yet another new town square. And so, on an apparently more venal scale, with Cragg.

So the fact that the Edinburgh show is mostly made up of big, recent, corporate-looking works is brave or possibly unwise. It might have been useful at this point in his career to remind us that Cragg wasn't always as he is now. When he first moved to Germany 35 years ago, the sculptor and his wife scoured the banks of the river Wupper for scraps of plastic – shards of bleach bottle, screw-on caps, the chassis of toy cars – which Cragg took home and sifted by colour into wall works. These were funny, elegant and, in an Arte Povera kind of way, humane. Something of the mudlarking spirit of that early Cragg gave sculptures such as Policeman (1981) a subversive charm.

This is all a long way from Hamlet (2009), in the Scottish National Gallery of Modern Art's show. Made up of thousands of thin plywood layers stacked one on the other, Hamlet is, at a guess, 12ft high by 5ft wide. Standing next to it is like looking up at a piece of geology – some wind-carved desert outcrop, say. In the same way that rock formations can mimic lions or knights, so Hamlet looks organic: through narrowed eyes, you can just about make out an embracing couple. Its manufacture was clearly mechanical, though, the results too orderly to have been eroded, their contours and surfaces too regular and polished. Hamlet is the product of a hugely sophisticated process involving 3D computer design and precision templates. It is not merely a big work and an expensive one; it is technologically very grown-up.

Were you to deduce Tony Cragg from Policeman and Hamlet, you might assume various things. The first is that Cragg sold out politically as he became more successful (which may or may not be so), the second that he is no longer an artisan but a manager (which is certainly true). Hamlet will have been made at his Wuppertal HQ, an ex-German army tank-repair shop employing dozens of skilled assistants. As Cragg's clientele has become more corporate, so has his practice. Or, possibly, vice versa.

The trouble with this picture is that it omits the many hundreds of Craggs of the 30 years between. Cragg is, famously, a boffin – the engineer son of one of the designers of Concorde. This is central to what you might call his moral view of the world – a Darwinian place of unending flux, with the fittest being selected and the weak going to the wall. He is fascinated not only by natural selection, but by de-selection. Pigs evolve, he says, and elephants; but what about "pigephants"? It is worth noting that the next valley to the Wupper's is the Neandertal, whence the doomed humanoids.

All of which is to say that change, experiment and Stakhanovite output are meat and drink to Tony Cragg. I can not think of another sculptor who has kept so tightly within the bounds of his discipline – no videos, no traipsing through mud – and yet pushed at those bounds so materially. The works in the SNGMA all date from the past 20 years, and yet they are made in ceramic, jesmonite, plaster, wood, steel, fibreglass, stone, bronze and several grades of steel. To these might have been added, from the same period, Kevlar, polystyrene and thermoplastic dice, although Cragg's own rigorous self-selection may have consigned these to evolutionary history.

You see this fascination with change not just in Cragg's restless variety, but in the air of many of his sculptures of being frozen between one state to another. In Camera looks like a cross between a camshaft and a shelf of jars; less a pigephant than a potshaft. If you're feeling fanciful, then you might see it as marking a point on Cragg's own evolution from hand-maker to machine-maker. Bent of Mind, a type familiar to Cragg fans from the past decade, combines the cartoon-convention swirl of an object in motion with a Bertelli-esque 360-degree profile. As you walk around the piece – and its torque demands that you do – your eye and mind struggle to tie it down. Just when you think you've found its biting point, Bent of Mind slips repeatedly out of gear.

I think it's fair to say that Tony Cragg's febrile output will necessarily throw up the odd failure, that it wouldn't be living up to its evolutionary creed if it didn't. For there to be a fittest, there has to be a less fit. At times, as in Mental Landscape (2007), Cragg's formula becomes over-literal; his new fibreglass works are unpleasantly reptilian. But Cragg is still a wonderful sculptor. Forgive him his material success, and see this show.

Next Week:

Ossian Ward detects Signs of a Struggle at the V&A

Art Choice

When Napoleon rampaged through Italy's religious institutions, sacred artworks were scattered. Some ended up in the National Gallery, London, where Devotion by Design: Italian Altarpieces Before 1500 explains their stories and importance (to 2 Oct).