Vaisesika Sūtra 2.1.25

कार्यान्तराप्रादुर्भावाच्च शब्दः स्पर्शवतमगुणः ॥२५॥

kāryāntarāprādurbhāvācca śabdaḥ sparśavatamaguṇaḥ ॥25॥

[कार्य अन्तर अप्रादुर्भावात् च शब्दः स्पर्शवत् अगुणः॥
kārya = effect; antara = difference; aprādurbhāvāt = absence of the manifestation; ca = and; śabdaḥ = sound; sparśavat = possessing the touch; aguṇaḥ = without qualities;]

Difference in the effect is due to the absence of the manifestation of sound and touch, because of the absence of their qualities.