vastusattāvabodhārtham vastunaḥ sattāṃśāvabodhārtham / tatra abhāvāṃśe prameye, abhāvasya pramāṇatā /
For the purpose of knowing the existence of an object [and] for knowing its existent aspect. In that case, regarding the non-existent aspect as the object to be known, negation [functions] as a means of valid cognition.