Architect Louis Kahn, Design Museum, London

Louis Kahn is known for his aphorism about “asking a brick what it wants to be” – the idea that a natural language of architecture will emerge from the innate properties of materials. It’s a good line, almost up there with Mies van der Rohe’s “less is more”. But not quite.

Kahn (1901-74) may have his place in the architectural pantheon along with Mies, Le Corbusier and Frank Lloyd Wright but he remains far less known. So much so that when his body was found in a lavatory in New York’s Penn Station, it lay unidentified for four days.

This relative lack of fame is perhaps because his buildings are in more obscure places – the Salk Institute in La Jolla, California; the National Assembly Building in Dhaka, Bangladesh; the Kimbell Art Museum in Fort Worth; the Centre for British Art at Yale – rather than in the biggest cities. Perhaps it is because his massive, Roman-inspired forms proved more difficult to copy.

Whichever it is, Kahn’s work has lasted better than that of his contemporaries. The Kimbell, with its seemingly simple vaults and serene light, is architecturally one of the world’s most important galleries, and it was Kahn who returned to modernism a concern with materials and mass, with archetype and archaeology.

Even so, some, including me, have yet to be fully convinced. Although I can admire the grandeur of his finest spaces, the beauty in the detail and the almost Roman scale of his best work, I find something simplistic about it, the same sense you get from the annoying aphorisms that clog up the walls in this exhibition, entitled Louis Kahn: The Power of Architecture, at London’s Design Museum. “Structure, I believe, is the giver of light”, “The sun never knew how great it was until it hit the side of a building”. And so on.

It reads like architecture’s mystical self-help manual. So can this exhibition convince the unenlightened?

Despite the fact that it is quite a good show, I’d have to suggest that the answer is no. Here’s Kahn again: “A room is not a room without natural light”. If that is so, then this exhibition is in a room that is not a room, but a space whose bland, blind whiteness makes a mockery of the work of an architect obsessed with the quality of light.

What has been done well, though, is the narrative of Kahn’s development from Estonian-born immigrant to a long career in Philadelphia. From darkly shadowed Beaux Arts decorative student drawings through early urban designs for Philadelphia and on to densely scrawled notebooks, there is plenty of the authentic material often lacking in architecture exhibitions. There are some exquisite original working models revealing the handicraft of design, and plenty more massive new ones that show very little.

But there is also a degree of confusion, which makes it a little difficult to understand the architect’s development. A map of Roman ruins engraved by Piranesi that used to hang on Kahn’s office wall is difficult to reconcile with a massive model of his proposed 1950s skyscraper (designed with Anne Tyng – good to see a woman credited, finally). Its structure was influenced by the discovery of DNA, a sci-fi diagrid structural wonder that powerfully influenced the Japanese Metabolists and Norman Foster (see his Hearst Tower in New York), as well as Richard Rogers (the bracing on his Centre Pompidou and since).

A room dedicated to Kahn’s posthumously realised Four Freedoms Park, a Franklin Delano Roosevelt memorial in New York, includes the wonderful original model but fails to communicate the almost antique, hewn quality of the work. These ideas all seem to exist in different worlds, and no attempt is made to resolve or explain the gap between the low and the high tech.

Another lurking problem for anyone attempting to explain Kahn’s vision is that his son got there first. Nathaniel Kahn’s 2003 film about his father, entitled My Architect, is perhaps the best film about architecture ever made. Not only does it deal with the buildings and the career but with the obsession, with how architecture colonises an entire life: Nathaniel’s powerful memory of neglect by a father he wish he’d known better is almost unbearably moving. Nothing in this exhibition comes close to that emotional impact and, of course, nothing comes close to the power of Kahn’s best buildings. If you want to be convinced, you’ll still have to see them.

‘Louis Kahn: the Power of Architecture’, designmuseum.org, to October 12

Photographs: Raymond Meier; Sue Ann Kahn; Iwan Baan; Elizabeth Felicella; Robert LaPrelle