________________ INTRODUCTION xiii foot-steps are being followed even to-day in the Navya-nyaya school. Vedanta also did the same. The Vedanta-paribhasha and the like are its fruits. As regards the Jainas, they have mostly composed works on logic since their entrance into the philosophical field. The Nyayavatara of Siddhasena, the Nyaya-vinischaya of Akalanka, the Pramana-pariksha of Vidyananda, the Parikshamukha of Manikyanandi and the Tarkabhasha of Yasovijaya, are some of the Jaina works on logic. As a result of the emphasis on the exposition of pramanas in the works on logic the discussions on jatyuttara and nigrahasthana that were considered as the primary ones in ancient logic, became secondary in the Medieval Age. Moreover the method of the jatyuttara 'was considered as improper. Dharmakirti through his Vada-nyaya criticised the method of jati and nigrahasthana and proved them to be futile. In his Nyaya-bindu, he wrote only one sentence to condemn jatyuttara and showed that jatyuttara is not a defect (dushana) but a fallacy of defect. In logic, when we analyse the nature of svartha-anumana (inference for one's own self) and parartha-anumana (inference for others), the analysis of jatyuttaras becomes easier and their futility becomes apparent. It is, therefore, natural that the importance of the discussion of jatyuttara should lose its significance. The main line of demarcation between ancient and medieval logic consists 'in the fact that whereas in ancient logic the discussion of jati and nigrahasthana occupied primary place, it became secondary in the Medieval Age. The great popularity and prominence of the study of Nyaya in Medieval Buddhism is clearly demonstrated by the fact that it produced more first class works on Dialectics than upon the nature and realisation of Nirvana. If there is any maturity in the works on Sunyavada or Vijnanavada, it is due to their methods of logical treatment. The clever exposition of the Vijnanavada and the Sunyavada became possible only with the help of dialectics. Even the refutation of the logical process could be supported only by logical method. The works composed on logic in medieval period formed a separate class, so important
