As Boston’s new Institute of Contemporary Art building was unveiled to the public, “What people were saying was that they couldn’t believe a building so audacious, so venturesome, could be built in — of all places — Boston. They were asking whether the ICA marked a watershed in the history of local architectural taste. Boston has been widely known, for a generation or more, as a conservative town architecturally, despite its liberal politics. To understand why, you have to know some history.” Robert Campbell explains.