The history of Indian Philosophy is a record of many different forms and types of philosophical thought. There is hardly any system in the history of Western Philosophy which has not it's parallel one or other of the systems of Indian philosophy. But of the Indian systems, the Vedanta has received the greatest attention and it has sometimes passed as the only Indian system worth the name. This is but natural. The Vedanta with its sublime idealism has an irresistible appeal to the moral and religious nature of man. It has been, and will ever remain, a stronghold of spiritualism in life and philosophy. It is like one of "the great living wells, which keep the freshness of the eternal, and at which man must rest, get his breath, refresh himself." "The paragon of all monistic systems," says William James, "is the Vedanta philosophy of Hindustan." Although we do have not such a sublime monism in the Nyaya, its contribution to philosophy is not inferior in any way. The other systems-the Vedanta has not excepted-have been greatly influenced by its logical and dialectical technicalities. In their later developments, all the systems consider the Naiyayika as the most powerful opponent and try to satisfy his objections. The understanding of their arguments and theories presupposes, therefore, the knowledge of the Nyaya.
As a system of realism, the Nyaya deserves special study to show that Idealism was not the only philosophical creed of ancient India. Then, as a system which contains a thorough refutation of the other schools, it should be studied before one accepts the validity of other views if only to ascertain how far those views can satisfy the acid test of the Nyaya criticisms and deserve to be accepted. But above all, as a thoroughgoing realistic view of the universe, it supplies an important Eastern parallel to the triumphant modern Realism of the West and contains the anticipations as well as possible alternatives of many contemporary realistic theories. The importance of the Nyaya is, therefore, as great for the correct understanding of ancient Indian philosophy, as for the evaluation of modem Western Philosophy.
The theory of knowledge is the most important part-in fact, the very foundation of the Nyaya system. This book is an attempt to give a complete account of the Nyaya theory of knowledge. It is a study of the Nyaya theory of knowledge in comparison with the rival theories of other systems, Indian and Western, and a critical estimation of its worth. Though theories of knowledge of the Vedanta and other schools have been partially studied in this way by some, there has as yet been no such systematic, critical and comparative treatment of the Nyaya epistemology. The importance of such a study of Indian realistic theories of knowledge can scarcely be overrated in this modem age of Realism.
The scope of the book is limited to the history of the Nyaya philosophy beginning with the Nyaya-Sutra of Gautama and ending with the syncretic works of Annam Bhatta, Visvanatha and others. It does not, however, concern itself directly with the historical development of the Nyaya. There is ample evidence to show that Nyaya as an art of reasoning is much older that the Nyaya-Sutra. We find references to such an art under the names of Nyaya and vakovakya in some of the early Upanisads like the Chandogya (vii. 1.2) and the Subala (ii). It is counted among the upangas or subsidiary parts of the Veda (vide Caranavyitha, ii; Nyaya-Sutra- Vrtti 1.1.1). It is mentioned under the names of anviksiki and tarkasastra in some of the oldest chapters of the Mahabharata (vide sabha, anusasana and santi parvas). We need not multiply such references. Those here given to show that the Nyaya as an art or science of reasoning existed in India long before the time of Gautama, the author of the Nyaya-Sutra. As a matter of fact, it has been admitted by Vatsyayana, Uddyotakara, Jayanta Bhatta and others that Gautama was not so much the founder of the Nyaya as its chief exponent who first gave an elaborate and systematic account of an already existing branch of knowledge, called Nyaya, in the form of sutras or aphorisms. It is in these sutras that the Nyaya was developed into a realistic philosophy on a logical basis. What was so long mere logic or the art of debate became a theory of the knowledge of reality. It is for this reason that the present work is based on the Nyaya-Sutra and its main commentaries.
So far as the account of the ancient Nyaya is concerned, my sources of information are mainly the Nyaya-Sutra, Nyaya-Byaya-Bhasya, Nyayavarttika Nyayavarttikataparyatika, Tatpryaparisuddhi, Nyayamanjari and Nyayasutravrtti. In my account of the modern and syncretist schools of the Nyaya, I have mainly made use of Gangesa’s Tattvacintamani with the commentary of Mathuranatha, Jagadisa’s Tarkamrta, Annam Bhatta’s Tarkasamgraha and Dipika, Varadaraja’s Tarkikaraksa, Kesava Misra’s Tarkabhasa and Visvanathas’ karikavali with Siddhantamuktavali and Dinakari. I have also consulted several English expositions of Indian Philosophy, like D. Jha’s Nyaya Philosophy of Gautama, Sir B. N. Seal’s Positive Sciences of the Ancient Hindus, Sir S. Radhakrishna’s Indian Philosophy, Dr D.M. Datta’s Six Ways of knowing, Professor Keith’s Indian Logic and Atomism, Dr S. N. Dasgupta’s History of Indian Philosophy, and MM. Kuppusvami sastri’s A Primer of Indian Logic. My indebtedness to these and other works has been indicated by footnotes in the proper places.
The method of exposition adopted in the book is comparative and critical. I have always tried to explain and develop the ideas and theories of Indian philosophy in terms of the corresponding ideas and concepts of Western Philosophy. The great danger of this is the tendency to read, consciously or unconsciously, Western ideas into Indian philosophy. I have taken all possible care to guard against the imposition of foreign ideas on the genuine thoughts and concepts of Indian philosophy. As a general rule, the different parts of the Nyaya theory of knowledge have been first explained and compared with those of the other systems of Indian philosophy. For the sake of completeness, the Indian theories have sometimes been elaborated in such detail as to give one the impression of prolixity. I have then undertaken a discussion of the Indian views from the standpoint of Western philosophy. No attempt has been made to affiliate the Indian views with parallel views in Western philosophy. Such an attempt cannot surely do justice to the originality and individuality of Indian thought. While bringing out the points of agreement between Indian and Western philosophy, their difference and distinction have not been ignored and passed over. I have not been able to support or justify the Indian theories on all points. It has been found necessary to modify them in some places and supplement them in the light of Western philosophy. At the same time, I have duly emphasised the special contributions of Indian philosophy towards the solution of the problems of knowledge discussed in Western philosophy.
In conclusion, I take this opportunity to express my gratitude first to the late lamented Professor Henry Stephen, of revered memory, who by his life and teaching made the study of Western philosophy popular among Indian students and infused into my youthful mind the spirit of an intensive philosophical study. I have also to acknowledge my indebtedness to Sir B.N. Seal, who was a versatile genius and an eminent authority in Indian and Western philosophy, and from whom I received great inspiration and valuable guidance in the early days of my research in Indian philosophy. I have to express further my deep sense of gratitude to Professor K.C. Bhattacharya, a profound thinker and astute metaphysician, who for some time held the George V Chair of Philosophy at Calcutta University. It was my proud privilege to sit at his feet and discuss and clear up some of the abstruse problems of logic and philosophy treated in this book. I have to acknowledge with thanks the great help I have received from MM. Pandit Sitaram Sastri, of Calcutta University, while studying some original works of the Nyaya philosophy.
I have to express further my most thanks to the great savant, Sir S. Radhakrishnan, George V Professor of Philosophy, Calcutta University, and Spalding Professor of Eastern Religions and Ethics, Oxford University, for the constant encouragement, help and guidance I have received from him in completing this work. My thanks are also due to my esteemed friend and talented writer, Dr D.M. Datta of Patna College, for reading considerable parts of the manuscript and for making valuable suggestions.
