 True, in texts like the Hetucakra of Dignāga (which was taken up in detail by Dharmakīrti in Pramāṇavārttika IV and Pramāṇaviniścaya III), a version of the triple criterion (trairūpya) for good reasons and the operators “partial presence,” “complete presence,” and “complete absence” were correlated to yield a series of nine types of reasons, types that are abstracted from content and subject matter. Not inappropriately, the great historian of logic, Innocentius Bocheński, in the chapter on Indian Logic in his History of Formal Logic, stated that the Hetucakra thus suggested an awareness of formal considerations. R.S.Y. Chi, in his Buddhist Formal Logic (Chi 1984), went several steps further and attempted to show that the Hetucakra, taken in its formal aspects, might present a number of interesting features to a modern logician. That being said, there is certainly much more to “good reasons” satisfying Dharmakīrti’s triple criterion than simple formal validity. The term “ascertained” (niścita), when unpacked by Dharmakīrti and his commentators, demands that good reasons must be sound (i.e., the premises must in fact be true and the conclusion must follow from them), that their three characteristics must be ascertained, and that the opponent have the appropriate “desire to know” (jijñāsā) something new that he does not already know. This latter demand leads to a host of other requirements: in order to be convinced of something new the opponent must have the requisite doubt, understand the terms and accept the subject of debate. In short, good reasons involve formal considerations (what follows from what?); factual considerations (what is so? what is true?); epistemic considerations (what needs to be known in order for people to genuinely know something else? when is doubt possible?); and what can be termed “rhetorical considerations” (what is newly convincing to whom? when does the debate have a point and when does it fall flat?). The weighting of these aspects in the theory of the “triple criterion” changes over history in complex fashions. At certain points what were factual matters become epistemic matters, and this even leads to interesting reorientations of the triple  criterion.[51]