ART Joseph Kosuth Irish Museum of Modern Art, Dublin

You can't avoid a little head-jolt at the plunging, rectilinear perspectives of the East Wing of the Irish Museum of Modern Art, where Joseph Kosuth, a founding father of 1960s Conceptualism, throws the architecture naked with another vast, wall-carpeting hypertext. Designed on Apple Mac, the fonts are sized and measured to fit the 300-odd metres of temporarily black-painted corridor wall; the letters sliced by vinyl-cutters for paste- up. The job took Kosuth's team five weeks, with elaborate respect paid to windows, doors, key-punch panels and bolted connections for CCTV eyes.

Titled "Guests and Foreigners, Rules and Meanings" - as were some recent European outings in Oslo, Como and Linz - the show enthusiastically doffs a cap to its hosts by dedicating itself to modernist heroes, James Joyce and Ludwig Wittgenstein. The latter, always an informing principle for Kosuth, is invoked for his later years, some of which were spent in Ireland.

A parallel ribbon of text from each, about the exhaustion of words, runs eight-feet high either side along the corridor, under an obscure constellation of names (writers, scientists and architects). Along the wainscot, another text details ceremonies of the Roman rite, in parallel with a paranoidally arresting regimen for sanatorium patients. Elsewhere floats another frozen screen-saver: a Walter Benjamin text about the impossibilities of translation - in English, then translated into Irish.

There are academic paragraphs on etiquette, anthropology and psychology, while punchier epigrams jazz up the wall in silver highlights: existential chucklers from Camus ("Sisyphus was basically a happy man") or Artaud ("All writing is pig-shit"). Most engaging, in grey typographical blocks, are secular-hagiographical excerpts on Joyce and Wittgenstein. The Joyce material is well-familiar to Dubliners, but less so with Wittgenstein (holing up in Dublin hotels or remote rural hovels; resisting Killary fishermen in their misidentification of seabirds; dismissing those who fight shy of abstract reasoning as "Gestalt-blind"). Engaging and thought- provoking, this is art as pen-portrait documentary.

Meanwhile, tucked into an enfilade of rooms off the corridor, Kosuth enjoys his own retrospective: from the eternal chair / chair-photo / dictionary definition (1965); through the (ironic?) didacticism of the reading-room and the Ten Partial Descriptions (1979); to Freud's scribbled annotations to "Fetischismus" rendered in eyesore red neon (1986). These arcane conceits, zerologically pared, are demonstrated again as "forms of presentation"; drawing attention to architecture, positioning and effect as much as logico- aesthetic propositions.

Some rooms simply degenerate into sad CV material: laserprints of recent shows; a shuffling carousel of slides documenting 1960s work; baffling scrapbook samples. There's just so much of it: a dizzying wealth of amassed material, particularly the corridor wall - immaculately graffitied within the secular cathedral of the six-year-old museum. It leaks a sense of passionate intellect, despite its minimalist polish, its austere classicist aura.

As ever with Kosuth, it's down to whether you accept the critical assumptions which support his work (many generated by himself); or whether you regard this as rarefied publishing-by-association. Yes, this is an advanced exercise in the art-historic tradition Kosuth so derided. Yet its serene spatial impact, its enormous fascination and the implied interstices between the "stolen" texts - all succeed really elegantly.

Definitely a show for the thirsty of mind, this is an impressive, mock- constitutional monument to the word that rewards exhaustive attention. Maybe the museum should provide little stools-on-castors, so you could scootle comfortably across the waxed floors, pausing only to drink deep of the pleasure of the mounted text - never mind the "art as idea, as idea".

To 11 June (00353 1 6718666) Mic Moroney