In the West logic and epistemology are regarded as two separate but closely related branches of philosophy. Logic deals with inference which is accepted as a source of knowledge; and knowledge is the subject matter of epistemology. Since a mahor portion of our knowledge is obtained through inference, epistemology depends on logic for justification of the knowledge-claim made on behalf of some of the beliefs. If a belief is true and can be shown to be the conclusion of a valid inference then it would be considered as knowledge. So a theory of inference which logic is to provide us with, must take into account the requirements of epistemology.

A theory of knowledge demands such a theoty of inference which will take care of the truth-giving aspect of an inference, in addition to the consistency or validity of reasoning. By truth-giving aspect of an inference we mean its role in discovering or proving a truth. It is something different from the truth-preserving or truth-transmitting aspect of an inference, because an inference in spite of being truth-preserving may not give a truth in the conclusion. In formulating a theory of inference logic must recognize an ideal of what an inference should be if it is to be a way of knowing. If in making an inference what we want is not merely that the conlcusion follows from the premises but also that we are getting a truth in the conclusion then the theory of inference must lay down conditions of truth as well as conditions of consistency or validity. Validity divorced from truth or mere formal validity is not enough for an inference if it is to be a way of knowing. So a theory of inference which combines truth with validity would be in order. Such a theory of inference alone can serve the purpose of epistemology properly.

In India, philosophy had been a comprehensive study. So Indian philosophy does not admit of branching into metaphysics, logic, epistemology, etc. There we find indeed a division of the subject-matter of philosophy into pramana (means of knowledge) and prameya (object of knowledge); and corresponsing to these, a theory of pramana and a tehory of prameya. Theory of pramana may roughly be equated with logic and epistemology in brackets. Theory of prameya on the other hand may be regarded as the Indian counterpart of metaphysics.

Every Indian philosophical system has its own pramana theory and prameya theory. A general observation which may be made about Indian theories of pramana is that almost all the philosophical schools in India accept anumana (inference) to be a source of knowledge; and none of the theories of inference propounded by them is a purely formal one, i.e. not concerned with the actual truth-value of either the premise or the conclusion, rather every Indian theory of inference lays doen conditions for correctness of the inferntial process in such a way that fulfilment of those conditions ensures the truth of both the premise and the conclusion.

In the present paper we shall consider only the Nyaya theory of inference to show that it is a theory of inference which is fit to serve the purpose of a theory of knowledge. We have chosen tne Nyaya theory of infenece in particular because the Nyaya school, specially the navya or mordern school, is well known for its pramana theory.

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