Vaisesika Sūtra 3.2.13

संदिग्धस्तूपचारः ॥१३॥

saṁdigdhaḥ tu upacāraḥ ॥13॥

[संदिग्धः (saṁdigdhaḥ) - doubtful; तु (tu) - but; उपचारः (upacāraḥ) - attribution;]

But the attribution is doubtful.