作成日: 2015-04-07 最終更新日: 2016-09-23 作成:野村 正次郎

Shoryu Katsura: Studies of Buddhist Logic in Japan


Your Holiness, it is my great honor to present a brief history of studies of Buddhist logic in Japan.

Unlike in Tibet where many Indian texts of Buddhist logic were transmitted and translated into classical Tibetan language, we Japanese had a very limited access to those materials because only four Indian texts of Buddhist logic were translated into classical Chinese language.

Namely, *Upāyahṛdaya attributed to Nāgārjuna (translated by *Kiṅkara/Kiṅkārya), a single chapter of *Tarkaśāstra attributed to Vasubandhu (translated by Paramārtha), Nyāyamukha of Dignāga and Nyāyapraveśa of Śaṅkarasvāmin (both translated by Xuanzang). Additional information could be obtained from Hetuvidyā section of Śrutamayībhūmi of Yogācārabhūmi attributed to Maitreya (translated by Xuanzang) and related texts such as Abhidharmasamuccaya attributed to Asaṅga (translated by Xuanzang).

Xuanzang spent 16 years in India to study Buddhist philosophy from 629 to 645. He must have studied not only Yogācāra doctrines but also Dignāga’s new system of Buddhist logic. He certainly knew Pramāṇasamuccaya and vṛtti but did not translate them into Chinese; it is recorded that another great Chinese translator Yijing translated Pramāṇasamuccayavṛtti but it is not extant and does not seem to have been studied by Chinese Buddhist scholars.

Thus the students and followers of Xuanzang studied Buddhist logic chiefly through Nyāyapraveśa that is a short introductory manual for studying Nyāyamukha. They composed many commentaries on Nyāyapraveśa and Nyāyamukha but they are either lost or exist only in parts or fragments. It is the Great Commentary on Nyāyapraveśa written by Kuiji, direct disciple of Xuanzang, that became most influential text of Buddhist logic in East Asia.

It is most likely that Dōshō (629-700), who spent 7 years in China to study Buddhism under Xuanzang, brought back the discipline of Buddhist logic to Japan. He did not leave any work of his own on Buddhist logic but he initiated Japanese school of Yogācāra-vijñānavāda called Hossōshū that developed Japanese studies of Buddhist logic. The two most prominent Japanese Buddhist logicians in Nara period are Gomyō(750-834) and Zenshu (723-799). Gomyō for example wrote Daijō Hossō Kenshinshō in which he devoted one chapter to Hetuvidyā. He not only succeeded in presenting Buddhist logic in a systematic way but also gave a long discussion on Xuanzang’s famous/notorious proof of vijñaptimātratā that the latter was supposed to have presented while he was still in India and was not refuted by any Indian colleague.

There is not enough time to present a further development of Japanese studies of Buddhist logic. I just want to mention that the tradition of studying Buddhist logic based on Nyāyapraveśa continued not only in Nara but also at Mt. Hiei and Mt. Koya, and during Edo period many Jōdoshinshū priests studied Buddhist logic and wrote scholarly works. It is a characteristic of Japanese studies of Buddhist logic that they tended to focus on the thirty-three faults of Hetuvidyā, namely, 9 erroneous theses, 14 erroneous reasons and 10 erroneous examples. They did not pay any attention to pramāṇa theory.

It may be interesting to note in passing that, just like Tibetan monks, Japanese Buddhist monks also practiced a debate on various philosophical topics. Such a debate is called rongi in Japanese. It was carried out not only in Nara but also at Mt. Hiei and Mt. Koya. Gradually rongi began to be held at the time of promotion of a monk to a higher status and became nothing but a stylistic formal ceremony. In Jōdoshinshū tradition, however, their priests are still continuing to debate on some given topics during their summer retreat (ango) every year.

In this connection, I would like to mention what I think is the main distinction between Japanese and Tibetan traditions of Buddhist logic. As we have just seen, Japanese tradition chiefly relied upon Nyāyapraveśa and Dignāgean system of Buddhist logic, while Tibetan tradition was well acquainted with the further development of Buddhist logic by Dharmakīrti and his followers, of which Japanese were totally ignorant. Tibetan Buddhist scholar-monks composed many commentaries on Dharmakīrti’s works and further developed Buddhist logic in their own way. However, they did not pay much attention to Dignāga, probably because the two extant Tibetan translations of Pramāṇasamuccaya & vṛtti were rather confused. Tibetans tended to understand Dignāga in the eyes of Dharmakīrti. Tibetan tradition developed both Buddhist epistemology (pramāṇa) and logic (vāda/hetuvidyā), while Japanese and East Asian tradition in general was not fully informed of and consequently lacked interest in epistemology.

Towards the end of Edo period Japan stopped closing its door to the foreign countries and with the arrival of new Meiji period we started learning many western disciplines of arts and sciences from European and American countries. When Japanese intellectuals of Meiji period faced with western logic derived from Greek tradition, some of them like Kira Kōyō (1831-1910), Ōnishi Hajime (1864-1900) and Murakami Senshō (1851-1921) tried to understand it in comparison with or from a perspective of Buddhist logic.

At about the same time Japanese Buddhist scholars went to western countries to learn to read Indian Buddhist texts in Sanskrit and other languages. They brought back a new methodology of Buddhist studies that can be called ‘modern Buddhology’. Sooner or later they started to discover that there was a further development of Buddhist logic after Dignāga. I just name one of them. Ui Hakuju (1882-1963) studied Nyāyamukha with the knowledge of newly acquainted Indian logic. He also studied *Upāyahṛdaya and other texts of Buddhist logic.

After the second world war, thanks to the heroic efforts of Rahula Sankrityayana who went to Tibet to photo Sanskrit manuscripts of Buddhist texts before and during the war, Sasnkrit version of Pramāṇavārtika of Dharmakīrti and other pramāṇa texts became available, which made some Japanese Buddhist scholars start struggling with those new materials.

Ui Hakuju’s disciple Nakamura Hajime (1912-1999) among many contributions to Indian and Buddhist studies translated Nyāyabinduṭīkā of Dharmottara into Japanese, compiled a dictionary of Buddhist logic, and tried to understand Indian and Buddhist logic in comparison with western tradition of logic.

Kajiyama Yuichi (1925-2004) studied not only Dharmakīrti but also his successors such as Jñānaśrīmitra, Ratnakīrti and Ratnākaraśānti. Tosaki Hiromasa (1935-) translated the pratyakṣa chapter of Pramāṇavārtika into Japanese. Kitagawa Hidenori (1921-1975) and Hattori Masaaki (1924-) studied Tibetan translations of Dignāga’s Pramāṇasamuccaya & vṛtti. They divided their tasks, namely, Kitagawa worked on the second, third, fourth and sixth chapters and Hattori on the first and fifth chapters. The former published A Study of Indian Classical Logic – Dignāga’s system – in Japanese (1965) and the latter published Dignāga on Perception (Harvard Oriental Series, 1968) and an edition of Tibetan translation of Pramāṇasamuccayaṭīkā of Jinendrabuddhi (1982). The four scholars mentioned above all went to India to study, became internationally well known and made the eyes of Japanese Buddhist scholars open to the world. I have been quite lucky because I was a student of Kajiyama and Hattori at Kyoto University and personally acquainted with Kitagawa and Tosaki. I must say that I learned a lot from all of them.

There is no time to present important achievements made by my colleagues in Japan. However, please allow me to introduce some of my academic works and my on-going projects. I graduated from Buddhist studies at Kyoto University by submitting a graduation paper on Nāgārjuna’s Vigrahavyāvartanī (1966), obtained MA from the graduate school of Kyoto University by submitting a thesis on Dharmakīrti’s theory of self-cognition (1968) and went to the University of Toronto, Canada, to obtain Ph.D. by the study of Tattvasiddhi/Satyasiddhi of Harivaman (1974). I also obtained D. Litt. Degree from Kyoto University by my study of vyāpti in Indian logic (1986). Upon returning to Japan, I taught at Kyoto Sangyo University for a year and a half and at Hiroshima University for more than 27 years before I joined Ryukoku University in 2004 from which I finally retired 5 days ago.

Regarding the studies of Buddhist logic, I published a series of annotated Japanese translation of Nyāyamukha, edited the proceedings of the third International Dharmakīrti conference held in Hiroshima, edited together with Ernst Steinkellner a volume of A Role of Example in Classical Indian Logic, and published a new English translation of Mūlamadhyamakakārikā together with Mark Siderits. I shall present those three books to your Holiness.

For the last ten years I have been engaged in producing a critical edition of Sanskrit text of Jinendrabuddhi’s Pramāṇasamuccayaṭīkā chapters 3, 4 and 6 and reconstructing Sanskrit text of the corresponding Pramāṇasamuccayavṛtti. With a help from a number of my friends I have more or less completed the work and will prepare them for publication. I will also publish soon the first English translation of *Upāyahṛdaya together with Brendan Gillon. And finally I shall complete Japanese translation of Ratnākaraśānti’s Prajñāpāramitopadeśa from a newly discovered Sanskrit text.

At the age of 71 I am not sure how long I will live but I would like to spend most of the remaining time to continue to study Buddhist logic.

Thank you very much for your kind attentio.