For the blind man in the dark room looking for the black cat that isn't there, ICA, London

Little reason to purr with delight

As the the rather long-winded title suggests, there's a black cat somewhere to be found in this new group show at the ICA, and I eventually came across the sound – not the physical presence – of it about halfway up the stairs between the ground-floor and first-floor galleries.

The cat had been interviewed almost 30 years ago by a playful Belgian artist and poet called Marcel Broodthaers, and what I could hear was a transcript of that interview from way back when. Every time the cat was posed a question, it gave the same answer: miaow. Here's the first bout of interrogation: "Is this one a good painting? Does it correspond to what you would expect from the most recent transformation which leads away from Conceptual Art to this new version of a certain kind of figuration, as one would say?"

Me neither.

And the show is not much more interesting elsewhere. Its big idea is ignorance – or, to put it slightly more attractively, the fun of not knowing – and it takes us on a spasmodic journey from Socrates to Maggie Thatcher. All the artists in the show are brooding on the problem of art and ideas, posing questions, thinking aloud. This is often a recipe for a great deal of boring and pretentious guff. It is here.

It begins with an entire wall of drawings and texts by Matt Mullican. There's the drawing of an outline of an empty box, for example, which asks you whether or not the box is full or empty. There are also lots of other drawings of different shapes and sizes, all crammed densely together on a wall: formulae, spirals, technical drawings; the words "symbol", "sign" and "emotion". Mullican wants us to see him thinking aloud about the problem of trying to arrive at some kind of notion of what an artwork might be. The cogs are turning and turning. But, generally speaking, are we really interesting in watching him think? And, more to the point, are we excited by the visual outcome of all that thinking? Does it arrest, excite or entertain us? Not really.

Fischli & Weiss are much more engaging because they make us smile in a video that sees them tramping through the Swiss countryside, dressed as a bear and a rat, posing each other unanswerable questions.

A little way away, I come across a collection of white tables made in odd geometrical shapes. They are on wheels. They could be pushed around. On these table tops there are collections of various abstract shapes, made out of wood, glass, felt, perspex, in various conjunctions with each other. I glance across at the wall texts for a point of entry. Here is one of them: "The performance lies in the non-expression of the (crossing of the) affects." Once upon a time, I would have felt guilty that I didn't quite know what a statement like this really meant. It would have set in motion a bout of miserable mental self-flagellation that might have lasted for up to three hours. Not any more. This time I look up at the ceiling – there's nothing much going on up there – and count to three.

Upstairs, we have the film by Rosalind Nashashibi and Lucy Skaer, which includes the image of Mrs Thatcher. It also takes in a very quick shot of a woman crying at the British Museum. Why? Why Not? I pass on. Out in the corridor I pause at a video. A thin, French-sounding logician is talking very fast about the fact that there is an infinite beyond the infinite. His hand flashes formulae across a blackboard with all the aplomb of Paul Daniels.

Oxford Street might be less painful, even at this time of year.

To 31 January 2010 (020 7930 3647)