‘We will never know what space is’. He is right, Louis Kahn, adding: ‘and what is talked about as space’. Yes, words are splendid ammunition for arguments, especially about that most volatile, most intangible, most central feature of architecture, space: as a refuge or an excuse, a cloak or an exaltation, but also quintessence, mystery, ‘the eye’s wrangle, the world’s potage, the rat’s star’.

‘Everything is space,’ claims a self-appointed avant-garde, reducing our architectural art to a decorative craft. All those glass, metal and plasterboard boxes of tricks which flood the architecture market confuse the end with the means; they are created for effect, but not the kind of effect which results from sufficient cause. To achieve ‘beauty with this beautiful vocation’ space must be contained, distinguished by precise boundaries from the heaviness and depth of the material which encases it, into which light breathes life.

But it is possible to combine that ancient heaviness – the wonders of Saqqara, for example, or of Istanbul or Cordoba – with a new, freer, suggestive space, a highly contradictory, defiant lightness of stone, a complex blend, rich in contrast, of earthen piles and the light which rains down upon them; reinforced concrete, a technical design illusion of the highest order, is indeed capable of consoling us for the loss of all those venerable, forgotten virtues of consistency and tectonics. Only this can incorporate our quest for new spaces and spatial prototypes into the admittedly most ancient yearning to feel secure, to sense the necessity: ‘thus and no other way’ each freshly stripped wall tells us, ‘accept me as I am’ and ‘live beside me’, ‘just let yourself go’. Cast stone, then, is the architect’s hope, the mason’s fear, the client’s challenge – and so often it is the writing on the wall for our culture of building. Now, at the beginning of the new millennium, when optimised dry construction techniques will celebrate their definitive and utterly banal victory, we initiates are beginning to realise that a touching legend is now taking shape, that in the 20th century there was a kind of building, extremely laborious, which succeeded one last time in producing architecture of note – what am I saying? – in producing architecture.

Déjà-vu enables us to recognise great buildings, which tell us what we always knew and had simply forgotten. The prefabricated shoeboxes and bubbles of this future brave new world will not permit the evocative murmur of that imperfect tense.