Nyāya Sūtras 2.30

2.30

nirṇayas tattvajñānaṃ pramāṇānāṃ phalam, tadavasāno vādaḥ, tasya pālanārthaṃ jalpaviṭaṇḍe/ tāv etau tarkanirṇayau lokayātrāṃ vahata iti/ so 'yaṃ nirṇayaḥ prameyāntarbhūta evamarthaṃ pṛthag uddīṣṭa iti/

Ascertainment is the knowledge of reality, the fruit of the means of valid cognition; philosophical debate culminates in it; disputation and cavil are for the sake of protecting it. These two, hypothetical reasoning and ascertainment, conduct worldly affairs. This ascertainment, though included within the object of valid cognition, is mentioned separately for this purpose.