サブトピックとサブサブトピックの作成方法について

That’s a real downer! How could tags be used to make it look to the casual user that there were subtopics. For example, I would like to have someone go to Science/PCT_Science/Individual/Conscious_Perception/Reorganization/Function_building and a few dozen such locations, most of them having been initiated by casual users. With only three levels of splitting, what hope do I have?