The Nyaya Theory of Knowledge has grown and developed as an answer to the challenges posed by Buddhist Naiyayikas. The Buddhists in keeping with their commitment to the ideology of momentariness maintained that ordinary perception and inference are possible only within the range of Kalpana, a creative faculty of mind. All communicable knowledge for them was possible a priori; there exists nothing in the world of experience that could really correspond to our ideas rooted in Vikalpa. The Nyaya, true to its realistic ideology defended the dualistic position maintaining that any knowledge as an authentic human concern has to depend upon Padzirhta, i.e., what there exists in the world of reality. The possibility of a priori knowledge is denied and possibility of a strict empiricist position is maintained.

Jayanta Bhattz has not only faithfully recorded the controversy between Nyaya and Buddhist Philosophers, he has also in his right as an original thinker contributed his own share to the lot of Nyaya. Dr. Chakra Dhar Bijalwan has carefully studied the role of Jayanta as a historian of Philosophy and also as a Naiyayika.

This book is the result of painstaking research and critical evaluation of various issues and views. It is bound to help all those scholars who care to study Indian epistemology. Dr. Bijalwan's book presents a landmark in the tradition of textual study of Indian Philosophy.

I have great pleasure in introducing to the scholars of Indian Philosophy and Sanskrit 'Indian Theory of Knowledge based Upon Jayanta's Nyayamalijari, by Dr. C. D. Bijalwan. Nyaya is generally held to be a very dry and difficult sastra. Fewer are, therefore, authentic expositions of this system. Dr. Bijalwan is well qualified to expound the Nyaya doctrines, since he has acquired sound training along both the traditional as well as modern lines. In the 18th and 19th centuries, when Sanskrit became known to European scholars, they wanted to work in the field of Nyaya, but could not break through the fort of its technical terminology. They have, thus, in that period just smelt the Nyaya texts and put them aside. In 1951, Prof. Daniel Henry Holmes Ingalls came forward with his excellent work entitled as 'Materials for the Study of the Navya - Nyaya Logic' and, thus, opened the gates for researchers to work in the field of Indian Logic. Soon after several scholars devoted themselves to the study of Nyaya and U.S.A, France, Austria and Australia became prominent centers of Nyaya Studies. Jayanta Bhatta was a scholar of versatile genius. He stood against the attacks made by Dinnaga. Dharmakirti, Dharmottara, etc., on the expositions of Gautama, Vatsyayana, Uddyotakara, etc., respectively and successfully re-established the superiority of Nyaya over other systems of Indian Philosophy.

Jayanta's success was based upon his extraordinary power to elaborate his own point of view in simple and lucid Sanskrit. The Nyayamailjari, therefore, has virtually become an outstanding manual of all the schools of Indian Philosophy in general and Nyaya in particular. In addition to analysing the nature, forms and methods of knowledge, Jayanta has also dealt with such problems as the locus of Rana. Refuting the Sarhkhya point of view, he rightly asserts that intellect (Buddhi) being an inanimate and unconscious principle, cannot be accepted as the locus of knowledge. His definition of Pramiina, as the sumtotal of conscious and unconscious facts (bodhdbodhasvabhava), is very much convincing and quite unique. The great Naiyayika has, however, overlooked or did not elaborately analyse some problems. For instance, he did not take cognizance of the facts which his posterior scholars referred to with regard to the Quality Theory of Knowledge. I am happy that Dr. Bijalwan has very aptly filled up the gaps and delineated all the aspects of knowledge on account of his first-hand study of the basic texts of all systems and made the present work as comprehensive and flawless as possible.

Dr. Bijalwan has discussed in detail the cardinal points of the Indian Theory of Knowledge and has done full justice to the subject. The present work embodies pioneering research on the Nyayarnaiijari in particular and other texts of Indian logic in general. I believe it will be warmly received by the scholars interested in this subject and will bring reputation to the author as a scholar of much promise. I congratulate Dr. Bijalwan for this excellent work and very much like that he further explores the treasure-trove of Indian logic.

In my humble attempt at preparing this book, I have taken Bhatta Jayanta's Nyclyamaiyari as the basic text and have also drawn upon the major works of almost all the relevant systems of Indian Philosophy. For a clearer, comparative and critical presentation of the subject matter, I have referred to the writings of modern scholars as well. Jayanta was the most outstanding Naiyayika of his time, but it is very strange that due recognition was so far denied to him by the scholars either hastily or negligently. Thus, we do not find any modern work devoted exclusively to his theory. A comprehensive work, giving proper place to his catholic approach in logic was still wanting and the present book is a modest Endeavour to fulfill this need.

I have tried to co-ordinate, compare and evaluate the answers given by various Indian thinkers to the questions concerning the nature, locus, forms and methods of knowledge. My own observations throughout the text find place wherever such necessity arose and also have been, without fail, given at the end of each chapter. This work is an improved version of my thesis approved by the University of Delhi for the degree of Doctor of Philosophy in 1972.

I can hardly find appropriate words to express my indebtedness to my parents, Pandit Narayan Datt Bijalwan and Shrimati Maheshvari Devi for their blessings for preparing this book. I am extremely grateful to my venerable teacher Dr. R. C. Pandeya, Prof. and Head of the Deptt. of Philosophy, University of Delhi, under whose inspiring guidance I prepared this work and who has also very kindly taken the trouble of writing a learned foreword to it.

It is my pleasant duty to express my sincere gratitude to my revered mentor Dr. Rasik Vihari Joshi, Prof. and Head of the Deptt. of Sanskrit, University of Delhi, who has very benignantly inculcated my interest in the Nyayasastra and who has also graced this book with an erudite Introduction.

I am specially thankful to Prof. Janaki Ballabha Bhattacharya for the help that I received from his English translation of a few portions of Nyilyamaiyari, published in some issues of Calcutta Review. For the names of other modern scholars, without whose works my task would have been much more difficult, I should like to refer the readers to the foot-notes and index.

During the preparation and finalisation of the script of this book I had the rare privilege of consulting the works of and receiving the blessings as well as valuable suggestions from Prof. V. Raghavan, Prof. R. N. Dandekar, Dr. R. K. Sharma, Prof. D. N. Shastri, Prof. Siddheshwar Bhattacharya, Prof. Dev Raj, Dr. Mandan Mishra, Prof. Gopika Mohan Bhattacharya, Prof. S. S. Barlingay, Prof. Anant Lal Thakur, Prof. R. C. Dwivedi, Dr. M. D. Balasubra-maniam Dr. J. D. Ganguli and Shri C. R. Swaminathan. I take this opportunity to pay my respectful homage to all of them.

I am indebted to Dr. G. P. Bhatt, Assistant Director, Philosophy Section, C. H. D. Ministry of Education, Govt. of India, New Delhi, for going through the manuscript and suggesting valuable improvements in it.

I have really no words to express my sincere thanks to my friend, Shri Rajendra Dhasmana, who has spared no pains in helping me in almost every stage of the production and publication of this work.

I am highly grateful to Shri B. R. Chawla, Proprietor, Heritage Publishers, Connaught Circus, New Delhi, for undertaking the publication of this book.