The two kinds of negation, paryudāsa and prasajya-pratişedha, in the Hetubindu and the Hetubindu-ţīkā

The two kinds of negation, implicative negation (paryudāsa) and pure negation (prasajyapratişedha), are well known to Indian philosophers and Buddhist logicians as well. Their functions are generally understood to differ from each other, and they have been one of the important topics for scholars of Indian philosophy. In the field of Buddhist logic, negation or negative reasoning is analyzed in the scope of non-perception (anuplabdhi) or logical reason for it (anupalabdhi-hetu). Dharmakīrti explains in his Hetubindu that non-perception is not mere negation (pratişedhamātra) of perception, viz., pure negation of it. He regards non-perception as implicative negation of perception. Dharmakīrti explains that only when man recognizes something other than X (anya-bhāva) which is identifīed with implicative negation of perception can he confirm the non-existence of X (tad-abhāva). For Dharmakīrti non-perception of X is a logical reason (hetusādhana) for confīrming the non-existence of X when the non-perception of X is regarded as implicative negation of ""perception of X"". Bhaţţa Arcaţa, a commentator on Dharmakīrti\u27s Hetubindu, expounds that non-perception of X means not only implicative negation of ""perception of X"" but also pure negation of ""perception of X"" : he states that the negative particle (an-) of the word ""non-perception (an-upalabdhi)"" means not only pure negation but also implicative negation. Arcaţa interprets pure negation of ""perception of X"" as non-existence of X (tad-abhāva), and he identifīes non-existence of X with something other than X (anyą-bhāva). A perception of something other than X causes the cognition of non-existence of X ; in this case, pure negation is regarded as having the same function as that of implicative negation in the logical reason of negation (anupalabdhi-hetu). Arcaţa\u27s interpretation of the same function of the two negations in negative reasoning derives from Dharmakīrti\u27s idea of ""the one and same valid cognition""(eka-pramāņa), the function of which simultaneously makes one understand both affirmation of X and negation of non-X. In order to understand the reason for Arcaţa\u27s interpretation, the present writer analyzes the function of one and the same valid cognition from the viewpoint of the two kinds of incompatibility (virodha). It is closely related to an incompatibility of contradiction (parasparaparihārasthitilakşaņa-virodha), but not to an incompatibility of contrariety (sahānavasthāna-virodha). Therefore the present writer further examines whether an incompatibility of contradiction is related to non-difference between the function of implicative negation and that of pure negation. As a result, on the basis of Arcaţa\u27s expositions, this paper shows the possibility that the incompatibility of contradiction, which is closely related to one and the same valid cognition, leads to Arcaţa\u27s interpretation of non-difference between the function of implicative negation and that of pure negation in anupalabdhi-hetu