Cases of past absence involve agents noticing in retrospect that an object or property was absent, such as when one notices later that a colleague was not at a talk. In Sanskrit philosophy, such cases are introduced by Kumārila as counterexamples to the claim that knowledge of absence is perceptual, but further take on a life of their own as a topic of inquiry among Kumārila’s commentators and their Nyāya interlocutors. In this essay, I examine the Nyāya philosopher Gaṅgeśa’s epistemology of past absence, according to which agents learn that a recollectable object or property was absent by inferring its past absence from failing to recall that object or property. Gaṅgeśa’s account is best appreciated against the backdrop of earlier theories and their shortcomings, and I begin by presenting historical views leading up to his. I identify two groups of views about the epistemology of past absence: recollection views, according to which cases of past absence involve agents recalling negative information; and recollection failure views, according to which cases of past absence involve agents failing to recall positive information. I reconstruct two early recollection views: a Bhāṭṭa view belonging to Uṃveka, and a competing Nyāya view belonging to Jayanta and Bhāsarvajña. I then examine Śālikanātha and Sucarita’s critiques of recollection views, following which I reconstruct a Bhāṭṭa recollection failure view belonging to Pārthasārathi. I then examine Gaṅgeśa’s critiques of Pārthasārathi’s account and the recollection failure view he constructs out of its shortcomings.