俱舍論疏 9.172

9.172

論「不爾所觀至父子等名」，答也。所觀有別，二義得成。由如父、子，從他生義名子、生他義名父。因果亦爾。

On the Śāstra's statement: 'Not so, for in terms of what is viewed, up to: the designations "father", "son", etc.': this replies. Because what is viewed is different, both meanings can be established. Just as with father and son: in the sense of being born from another, one is called 'son'; in the sense of generating another, one is called 'father'. Cause and effect are likewise.