This has been a dominant line of argument of late in the Historic Preservation movement, that "significant" buildings are worthy of preservation. However the confusion of "significance" for value does a tremendous disservice to the state of architecture in the world. After all what is "significant" is not always good, certainly Smallpox is a "significant" thing, but I seriously doubt that anyone would consider it a "good" thing.
A building can be significant in three ways:
1. A moment of history occurred there.
2. The building is an example of a style or movement or an architect's work.
3. The building is great as a building and a part of a larger environ, either rural or urban.
The first two ways of being significant are the most common ways that preservationists argue for the inclusion of modern buildings. These ways clearly are completely extrinsic to the building itself, so then the question of the building's intrinsic value is then apparently moot, or so it would seem.
The problem is that the building is a work of art created for a specific purpose. A building is made as a office building or school or church. A building also has to stand up to the elements and finally, a building as a work of fine art, has to move us to something greater, something that tells us about what it is to be human. (more will be discussed about this as time goes along)
A building must possess all three of these things : (as Vitruvius said: Utilitas, firmitas et venustas) These three things, brought together, lift a building to the realm of Architecture. In my opinion though, venustas (beauty) really is the spark that enervates a dead pile of brick and stone to architecture, but more on that later on.
However we live in a day that these things are really lacking in a LOT of buildings and in a lot of buildings that the critics call the great architecture of our day. There are a lot of buildings however, like smallpox, are so bad that they are the opposite of architecture. These are, seemingly without exception, the buildings foisted upon the world in the past century of the Modernist experiment. These are the buildings that are "significant!"
Now I'll allow, that there are SOME circumstances that allow for a bad building to be preserved for historic reasons. But I think those reasons need to be a lot more significant than "LBJ slept here one night." A hotel where MLK was killed or the Berlin Wall come to mind. These places have such a tremendous historic significance that the place rises above mere encyclopedic record, but it tells us something about being human, which is of course what art should do intrinsically. Here the lesson is extrinsic but somehow overwhelms an intrinsically bad architecture.
But the Berlin Wall, though a historic artifact did such incredible violence to the city that prudence practically requires us to tear it down. Document it, preserve it in memory and in archives, but don't sacrifice the city and our human endeavors to it. We need to have this sort of reason in dealing with the detritus of Modernism. Realizing it may be significant as in terms of a mistake, we should document it and tear them down.
This too goes for the second reason listed above. The significance of a particular work of architecture by a "famous" architect is even more removed from the intrinsic value of a building than its history. The IM Pei Third Church of Christ Scientist is the best example. The building is a failure on almost every level of Vitruvian goodness, but because it was made by "the great Pei" it should be preserved. So what? Because the building was built by a somewhat famous architect the owners and the rest of the city has to suffer an incredibly bad building?
A building's worth should be judged FIRST by its intrinsic worth. Does it work as a building, keeping out the wind and rain and keeping people comfortable? Does it stand up to time, or do we have to spend twice the initial cost every ten years keeping it up? Does it work as architecture, does it inspire us to something higher than the mundane and tell us about ourselves?
Or does it simply serve to stroke the egos of so many architecture critics who know better than the educated rabble?