As the scale and importance of preservation escalates each year, the absence of a theory and the lack of interest invested in this seemingly remote domain becomes dangerous. After thinkers like Ruskin and Viollet-Le-Duc, the arrogance of the modernists made the preservationist look like a futile, irrelevant figure. Postmodernism, in spite of its lip service to the past, did no better. The current moment has almost no idea how to negotiate the coexistence of radical change and radical stasis that is our future.

As we head towards a climax of preservation, ambiguities and contradictions build up:

• Selection criteria are by definition vague and elastic, because they have to embrace as many conditions as the world contains.

• Time cannot be stopped in its tracks, but there is no consideration in the arsenal of preservation of how its effects should be managed, how the ‘preserved’ could stay alive, and yet evolve.

• There is little awareness in preservation of how different cultures have interpreted permanence, or of the variations in material, climate and environment, which in themselves require radically different modes of preservation.

• With its own undeclared ideology, preservation prefers certain authenticities. Others – typically, politically difficult ones – it suppresses, even if they are crucial to understanding history.

• Through preservation’s ever-increasing ambitions, the time lag between new construction and the imperative to preserve has collapsed from two thousand years to almost nothing. From retrospective, preservation will soon become prospective, forced to take decisions for which it is entirely unprepared.

• From a largely cultural concern, preservation has become a political issue, and heritage a right – and like all rights, susceptible to political correctness. Bestowing an aura of authenticity and loving care, preservation can trigger massive surges in development. In many cases, the past becomes the only plan for the future…

• Preservation's continuing emphasis on the exceptional – that which deserves preservation – creates its own distortion. The exceptional becomes the norm. There are no ideas for preserving the mediocre, the generic.

In a global groundswell of revulsion, one particular genre has escaped the embrace of preservation. Open season has been declared on postwar social architecture. At its zenith, a strong public sector created the conditions in which architecture as a social project could flourish. At its nadir, a public sector, debilitated by the market, destroys it. There is now a global consensus that postwar architecture – and the optimism it embodied about architecture’s ability to organise the social world – was an aesthetic and ideological debacle. Our resignation is expressed in the flamboyant architecture of the market economy, which has its own built-in commercial expiration date.

Just like modernization – of which it is part – preservation was a western invention. But with the waning of western power, it is no longer in the West’s hands. We are no longer the ones that define its values. The world needs a new system mediating between preservation and development. Could there be the equivalent of carbon trading in modernization? Could one modernizing nation 'pay' another nation not to change? Could backwardness become a resource, like Costa Rica’s rainforest? Should China save Venice?

The march of preservation necessitates the development of a theory of its opposite: not what to keep, but what to give up, what to erase and abandon. A system of phased demolition, for instance, would drop the unconvincing pretence of permanence for contemporary architecture, built under different economic and material assumptions. It would reveal tabula rasa beneath the thinning crust of our civilization – ready for liberation just as we (in the West) had given up on the idea.