nacādarśanamātreṇa vastūnāṃ nāstitā siddhyati, satyapi vastuni kvacid adarśanāt, vastvabhāvena darśanamātrasya vyāptyasiddheḥ //
The non-existence of things cannot be established by mere non-perception, because sometimes things are not perceived even when they exist, [and] because the pervasion of mere perception with the non-existence of things is not established.