The book on the Metabolists I blogged about a couple of weeks ago has got me a bit hooked on conversations between Hans Ulrich Obrist and Rem Koolhaas. Obrist is a great interviewer anyway, but with Koolhaas there’s a dynamic that always seems to lead somewhere interesting.

RK: The Chinese city is for me a city that has built up a lot of volume in a very short time, which therefore doesn't have the slowness that is a condition for a traditional sedimentation of a city. Which is still for us the model of authenticity. Beyond a certain speed of construction, that kind of authenticity is inevitably sacrificed, even if you build everything out of stone and authentic materials – and that's a kind of irony.

There's no escaping the artificial in the new architecture, and certainly not in large amounts of architecture being generated at the same time.

There is something irritating about the automatic assumption of modernity, of the "inevitability" of, or the application of, state modernism. For instance, the conversion of the Reichstag is at least as strange as the emphasis on Prussian building, because these are two forms of innocence or naiveté, and to think that in the Reichstag you can exorcise the spirits with a new sort of dome is a sort of very polite gesture and a very compromised aesthetic. It is an equally weak intellectual stand.

For Foster, high-tech architecture was never dealt with in context, etc. To simply put a new head on a building that had an incredibly ambiguous history is innocent, or perverse, whatever you want to call it. Therefore, it's a very moving condition. Only now are all those civil servants realising that they actually have to inhabit Nazi buildings as their new ministries, with the anxieties that emanate from that, that demand exorcism - but do glass and steel drive out evil spirits?

HUO: What has happened in Berlin is that this city planning has happened without any involvement on the part of the different communities. I recently had a discussion with Itsuko Hasegawa in Tokyo, who thinks that one should advance a city in a participatory mode, so that the users of the buildings could almost say "This was my idea." What's your opinion?

RK: That's a very tricky question, because if you ask around and do real surveys, I think the current reconstruction is very popular, because the current mythology of going back to a traditional notion of plazas and streets could be a very populist platform. The other conditions, of inhabiting emptiness or living with scars and accepting the rampant oppositions of the East and West, and standing the distressed aesthetic, are much harder to grasp.

Therefore participation is not necessarily for people to be able to say "this is my idea, this is your idea" but on the contrary, a situation where it becomes impossible to say whose idea it really is, either the architect or the user. To imagine a process in which the intelligence of others is mobilised. Not to establish a dogma according to assumed preferences, which I think it what's happening.

Rem Koolhaas & Hans Ulrich Obrist, in Hans Ulrich Obrist Interviews Volume 1