Michael Craig-Martin review – sorry, but these lamps and filing cabinets just aren’t that interesting

<span>Twenty-first century still life … Michael Craig-Martin, Common History: Conference, 1999. </span><span>Photograph: Michael Craig-Martin/courtesy of Gagosian</span>
Twenty-first century still life … Michael Craig-Martin, Common History: Conference, 1999. Photograph: Michael Craig-Martin/courtesy of Gagosian

It’s an achievement to stretch a single idea as thinly as this retrospective of Michael Craig-Martin does. You start by laughing with him, in his clever classics of 1970s conceptual art. You end by laughing at him and the Royal Academy for thinking that his later, gapingly empty paintings and videos can really fill up the main galleries at Burlington House with their re-workings of the same exhausted theme.

That theme is objects. Craig-Martin has spent decades drawing and painting things, the more modern and ordinary the better: safety pins, forks, iPhones, wheelie suitcases. He depicts them with a designer’s precise perspective in a cool, clinical style with clear lines and neon-bright colours.

But why? There’s no sense of compulsion in these big yet pointlessly crowded pictures of stuff. Great modern artists of the object like Giorgio Morandi, Marcel Duchamp or Giorgio de Chirico convey a mystery and wonder in their often obsessive studies. Craig-Martin seems to do it because artists like this did it. His 2012 screenprint series, Art and Design, pays homage to modern masterpieces of object-art including Duchamp’s Bottle Rack and the pipe from René Magritte’s painting The Treachery of Images. In each case he turns the confounding original into one of his insta-drawings.

The reason, surely, that Craig-Martin’s pictures have a textbook quality is that he spent so much of his career teaching. He taught in art schools from 1966 onwards, most famously at Goldsmiths in the 1980s when his pupils included Sarah Lucas, Damien Hirst and Gary Hume.

The first work in this exhibition shows you what must have made him such an inspiring teacher, setting Hirst’s imagination, especially, alight. It is his most engaging work, An Oak Tree, created in 1973. A glass of water rests on a glass shelf against the white wall. The title, An Oak Tree, is printed on the wall. And a text explains how and in what sense this glass of water is actually an oak tree.

It is crucial to this work that there’s absolutely no visual similarity between the glass of water and an oak tree. You can’t “see” an oak tree in the way it sits on the shelf. Whatever makes it an oak tree is not visible. In the text beside it, Craig-Martin answers questions from an imaginary interviewer. The glass is not a symbol of a tree. Nor has he merely called it an oak tree: “What I’ve done is change a glass of water into a full-grown oak tree without altering the accidents of the glass of water.”

This conceptual artwork is a philosophical conundrum, reversing Magritte’s Treason of Images in which “This is not a pipe” appears under the picture of a pipe. But the philosophy this artwork is playing with is not modern. It’s medieval.

Craig-Martin, who was born in Dublin in 1941 and educated in Catholic schools in the US, parodies the Church’s most influential philosopher Thomas Aquinas. The 13th-century thinker ended the biggest theological debate of his time – how the body of Christ can be actually present in the bread and wine of the Eucharist – by applying Aristotle’s philosophy to explain that while the “accidents” – the superficial appearances – of bread and wine are unchanged, the “essence” is transformed into the holy presence of Christ’s body.

An Oak Tree is Aquinas meets Monty Python. Transubstantiation as farce. It claims a godlike power for the artist. Like a god, the artist can transubstantiate a glass of water into a tree. Or like Jesus who turned water into wine.

This must have electrified the young Hirst. His teacher helped him to see that conceptual art and the Duchampian readymade were a kind of magic that let artists turn glasses of water into trees, or dead animals into piles of cash.

If Craig-Martin’s early art gets its energy from the mixed feelings of a young man struggling with Catholicism, the banality of his later paintings seems to reflect an all-too-secular eye, free from guilt or superstition.

From the 17th-century painter Zurbarán seeing the Virgin Mary in (yes) a cup of water to the lifelong Catholic Warhol finding the sacred in a can of soup, many great still-life artists have been religious. They see the soul in stuff. Please don’t think I am proselytising for religious art. But if things are just things, how interesting can they be? I can’t share Craig-Martin’s endless fascination with electric torches, cork screws and credit cards. Then again it doesn’t seem like fascination. It’s more like the dry irony of someone who’s forgotten what he’s being ironic about.

Obviously the Royal Academy is in on the joke that eludes me because they confine An Oak Tree and his other engaging conceptual works from the 1970s to one room, before moving on to the supposedly bigger story of how he became a painter of snazzy, 21st-century still lifes. With their hard, cool colours in acrylic on aluminium these pictures seem to declare they are made for the “grey matter”, as Duchamp called the brain.

But there’s not enough brain food in them for a cat.