石凳說的合理。
義也是廣義的利(莊文雅的意思？)，但石凳說的義、利應是狹義的，即，利是不義之利。
With stonebench's criterion but my terminology, 義 is powered by the Will /願/願力/意誌, 利 is powered by desire/欲.
An empire with though less sophisticated culture and fewer higher pursues, at its beginning, still has some vision, which is the Will to create. It is a quality above the desire driven 利 . Therefore, it is still a form of 義, though limited. Yet precisely due to the lack of a more sophisticated culture and higher pursues, once the empire is founded, it slips into 利 more rapidly.
This explains stonebench's account of 蒙元.
In my terms, a nation falls alongside the weakening of the Will.
