因明入正理論疏 2.143

2.143

如聲論師對除勝論立聲常宗，耳所聞性為因。此中常宗，空等為同品，電等為異品，所聞性因二品皆離，於同、異品皆非有故，離常、無常更無第三，雙非二品有所聞性故。釋不共云：離常、無常二品之外更無餘法是所聞性，故成猶預，不成所立常，亦不返成異品無常故。其勝論師亦立有聲性，謂同、異性等並所聞性，若對彼宗非無同喻，故除勝論，對立成過。

For instance, when a Śabdika, against any opponent other than a Vaiśeṣika, establishes the proposition that sound is eternal with "having audibility by the ear" as the reason: here, for the eternal proposition, space and the like are the homologous class, and lightning and the like are the heterologous class; the reason "audibility" is excluded from both classes, being absent in both the homologous and heterologous classes. Outside eternal and non-eternal, there is no third category, since nothing that is neither of the two classes possesses audibility. In explaining the uncommon [reason, the text] says: outside the two classes of eternal and non-eternal, there exists no other phenomenon that possesses audibility; therefore, it causes hesitation, failing to establish the eternal that is to be established, and also failing to turn around and establish the heterologous non-eternal. The Vaiśeṣika also asserts a genus of sound, namely, that the universal-particular and the like are all audible; if formulated against their school, homologous examples would not be lacking. Hence, the Vaiśeṣika is excluded, and establishing it against others constitutes an error.