Designing a chair is a complex affair, not least because it forms a personal architecture around the human body, but for Ludwig Mies van der Rohe and his fellow Modernist pioneers, it represented an important means with which they could test their broader design philosophies. Mies is a giant figure in the architectural pantheon, and he produced some of the most influential landmarks in the architectural canon: the Bauhaus in Germany; the German Pavilion for the Barcelona Exhibition; the Farnsworth House in Illinois; the Seagram building in New York. But buildings, however impressive, don't travel well and it is as true of Mies as it is of many architects that their ideas are more familiarly encountered through their role as designers of furniture and decorative objects.
This said, you can trace in miniature the development of his intellectual principles by looking at some key pieces of his furniture, included in the current exhibition "Mies van der Rohe: Architecture and Design". The cantilevered tubular steel chair he designed in 1927 for his block of flats on the Weissenhof Estate in Stuttgart, with its continuous line of steel, provides a reading of Mies's concern with the interpretation of space as a continuum.
Tubular steel chairs have become so prevalent today that one has to remind oneself how novel the idea of using this material for smart furniture once was. Mies's solution to the structural problems that several other leading designers of the time were having with this material was characteristically straightforward: by employing curved front legs, he side-stepped the contemporary obsession with rectilinear angles, producing a silhouette which immediately declared its stylishness and design functionality.
But of all the chairs Mies designed, the Barcelona Chair and Stool are perhaps the best known. Initially, only two of each were built to furnish the German Pavilion at Barcelona's International Exhibition in 1929. The Pavilion - a concerto of marble, chrome-plated steel, travertine, water and light - was dismantled when the exhibition closed, but for Mies its furniture served a vital role in his architectural vocabulary.
For all its beauty, the chair presents a subtle essay on the deceptive claims of Modernism. Designed with scissor-style legs, cross-struts and leather cushions on straps stretched across the framework, the chair spoke of a machine aesthetic with its gleaming flat-pressed steel. The truth, however, was that the chair was not intended for mass production and was very labour-intensive to produce, with the steel welds requiring individual filing by craftsmen. Only after the Second World War did Knoll produce a version of the chair that bypassed these intricacies.
"Beauty is the splendour of truth," Mies was fond of saying, quoting St Augustine. The truth about Mies, however, as one admiring but frustrated architect featured on the excellent video tape in the exhibition states, is that, despite everything, the road he charted was a cul-de-sac: "You can't go beyond Mies. You can only replicate him." Beauty, perhaps, is not enough.
The issue of how to replicate beauty lies at the heart of another show on in Glasgow, "Food: Design and Culture". It explains how the task of bringing food to our tables - be they at home, in a restaurant, or attached to an aeroplane seat in front of you - involves the application of a bewildering array of design skills. Designing what, where and how we eat is a huge worldwide enterprise, one which has increasingly come to define how we perceive ourselves.
It used to be said by marketing types that they could tell what food we ate from our educational background, job or where we lived. Now they can tell all that and more just by reading our till receipts at the supermarket. The designing of food has become a volatile political issue, with the genetic modification of plants and animals, and the use of food packaging as advertising vehicles for entirely unrelated commercial products. Food design is now a minutely gauged science of second-guessing the public mood, as fickle as the pop charts. For scientists, getting a tomato to look tomatoey is now as technically demanding as designing a chair or a building.
`Mies van der Rohe: Architecture and Design': Burrell Collection, Glasgow (0141 649 7151) to 29 August. `Food: Design and Culture': Kelvingrove Art Gallery and Museum, Glasgow (0141 287 2700) to 22 August.