sadgrāhakapramābhāvān na vā sattā prasidhyati / pramāṇavinivṛttau hi nārthābhāve 'sti niścayaḥ //
Though existence cannot be established in the absence of a valid means of cognizing [something as] existent, when there is absence of a means of valid cognition, there can be no certainty about the non-existence of an object.