 Dharmakīrti, in Pramāṇavārttika I verse 40 et sq. and Svavṛtti, diagnosed the problem as one of bidirectional pervasions (i.e., coextensive concepts) seeming to force us to accept pratijñārthaikadeśahetu “reasons that are one part of the thesis” (e.g., when one says “sound is impermanent because it is impermanent,” then the reason “being impermanent” is also a part of the thesis that is being proved). He saw this undesirable consequence as one of the main challenges to logical thought, i.e., “inference,” being a source of knowledge (pramāṇa), for unless one can somehow rule out the problematic substitutions in what I have called the “tempting inference,” we would be saddled with having to accept as good a huge number of singularly uninformative reasons.