因明入正理論疏 3.93

3.93

述曰：此釋成。以立聲常宗，無質礙因，瓶體雖有，常、無礙無。虛空體無，二亦不立。有無雖二，皆是俱無。

Commentary: This is the explanatory demonstration. When establishing the thesis that sound is permanent by the reason of being unobstructed (amūrta), although the entity of a pot exists, permanence and unobstructedness are absent. The entity of empty space does not exist, and neither of the two [properties] is established either. Although existent and non-existent are two, both are cases of both being absent.