Beating the Bounds, Tate Britain, London

Works from the past 50 years that appear to fit a curator's agenda have no other clear relationship

Some trivia for the next time conversation flags at your dinner table: did you know that bounds can be beaten with the head of a child? Yes, beating the bounds was – is – traditionally done by choirboys with sticks of green willow, but parish edges can also be marked by bumping those same boys, up-ended, along them. Close your eyes and you can hear the howls.

This gem appears in the literature to a small show at Tate Britain called – yes – Beating the Bounds, part of the excellent Art Now series. Marking the limits of a parish is meant to sear them into the minds of the boys involved, so that beating the bounds with those minds, or at least with the skulls that contain them, does have a certain logic on its side. What all this has to do with art is less obvious.

The dozen or so works in Beating the Bounds cover half-a-century of British art-making, taking in painting, sculpture and film. No concept, though, which is odd. Given that the Tate's show is apparently about – ahem – "our being in the world", you'd have thought a bit of Martin Creed might have fitted the bill to a T. If the parish boundaries of art have been pushed outwards in the past 50 years, then it is artists such as Creed who have mainly done the pushing. But Beating the Bounds seems more narrowly concerned with tangible things – with the literal collision of the intellectual and the physical, as of young heads on cobblestones.

Thus Glenn Brown, whose intensely physical paint is also intently cerebral. When it comes to beating bounds, no one beats Brown; but then his limits are self-imposed.

Brown is an impasto-fetishist. He either takes the gooey pigment of a painter such as Frank Auerbach and renders it flat with a squirrel-hair brush, or he goes the other way and uses impasto so deep that it becomes sculptural. Examples of both tendencies are in this show. There's a flat-impasto painting, The Suicide of Guy Debord, and a new piece, Teen Age Riot, a desk so heavily encrusted in paint that it has come to look archaeological. Here, if you like, is the battle of material versus representation, and material wins hands down.

It's interesting to see Brown in the same room as his hero/nemesis, Auerbach, represented here by Small Head of E.O.W (1957-8). The German-born master is rising 80: his inclusion in Beating the Bounds aims to place him as father of a tendency in British painting of which Brown and another impastoist, Simon Ling, are younger members. Likewise with Brian Griffiths's Bear Face (2009), which sits opposite Eduardo Paolozzi's Kardinal Syn (1984). Paolozzi's tied-together plaster bust is the usual piece of overblown grimness, its word-play title matchingly heavy-handed.

Griffiths's bust also puns, although more amusingly: the work is a 10ft-high concrete recreation of the lid of a Yogi biscuit jar, which is to say that it is both bear-faced and, in the candour of its borrowing, bare-faced. But does it in any useful way descend from Paolozzi? That, maybe, is the problem. This show is full of nice things, most notably Helene Appel's painting of the sweepings from her studio floor, a one-man post-Povera manifesto. But how does it all hang together?

I've read and re-read the accompanying literature, and the nearest I can get to an answer is that most of the artists in Beating the Bounds are in some manner extreme. This may be in their handling of scale – cubic inch for cubic inch, Griffiths's bear's head is more scaled-up than the Statue of Liberty's – or it may be in their use of materials. (Brown's foot-thick impasto must surely count as an artistic ne plus ultra, while Richard Deacon's choice of glazed ceramic for his North-Fruit flies scandalously in the face of fashion.)

No matter how elegantly it has been done, Appel's focusing on floor dust is just plain obsessive. But in what way is Emily Wardill's 16mm film enactment of the parables from a stained-glass window materially left-field? Or, come to that, Des Hughes's sculptures of rusted knight attire?

The real answer, I'd say, is that some clever, young, Bataille-reading curator stumbled upon the bounds-beating metaphor, whooped with delight and squeezed his subjects to fit. That's all very well, but it leaves us with a skewed idea that good art and extreme art are one and the same, that mannerism will always win out over classicism. Actually, looking at the history of the last 50 years of British art, that seems to be true. But should it be?

Tate Britain, London SW1 (020-7887 8888) to 13 Dec