原文有做进一步解释，不过我还是没能看明白
For  instance,  consider  the following two  dimensions  “peak noise level during the night” and “noise level during the whole day”. Whichever the average noise during the day, low peaks during the night are always preferred  to  high  peaks  –  this  is  an  example  of  ordinal  independence.  However,  if  the  difference  of attractiveness between two night peak levels depends of the average noise level during the whole day, cardinal dependence  occurs.