維摩經玄疏 6.109

6.109

問曰：若本是體，從體起用，乃可言權是用，那得實亦是用？若皆是用，便無體、用之殊，亦無宗、體之別。

Question: If the fundamental is the substance, and the function arises from the substance, one may say that the provisional is the function; how can the ultimate also be the function? If both are the function, there would be no distinction between substance and function, nor any difference between central theme and substance.