Vaisesika Sūtra 3.1.07

अन्यदेव हेतुरित्यनपदेशः ॥७॥

anyadeva hetur ity anapadeśaḥ ॥7॥

[अन्य (anya) - other; एव (eva) - indeed; हेतुः (hetuḥ) - cause; इति (iti) - thus; अनपदेशः (anapadeśaḥ) - non-verbal designation; i.e., not expressible in words.]

It is indeed a different cause; hence, it is not verbally expressible.