An-upalabdhi, is, f. non-perception, non-recogni- tion. —Anupalabdhi-sama, as, ā, m. f. sophism, trying to establish a fact (e. g. the reality and eternity of sound) from the impossibility of perceiving the non-perception of it.
anupalabdhif. Non-recognition, non-perception (pratyakṣādyabhāva); nāsti ghaṭo'nupalabdheḥ (the knowledge of ghaṭābhāva is possible because the pratiyogī or counter-entity is not found with the non-entity or abhāva, that is, there being no upalabdhi or knowledge of the ghaṭa); one of the instruments of knowledge according to the Mīmāṁsakas, but not according to the Naiyāyikas. -Comp. -samaḥ a fallacy, trying to establish a fact (say, the eternity of sound) from the impossibility of seeing the non-perception of it.
Böhtlingk and Roth Grosses Petersburger Wörterbuch