How did the Nyaya school focus on logical and epistemological questions?

The Nyaya school, one of the six orthodox systems of Indian philosophy, is fundamentally concerned with the attainment of liberation through "right knowledge," which resolves the human suffering caused by ignorance of reality. To achieve this, the school developed a rigorous framework for logic and epistemology.12

Means of Valid Knowledge

Nyaya identifies four valid sources of knowledge:
* Perception (pratyaksha)
* Inference (anumana)
* Comparison (upamana)
* Testimony (shabda)1

The Nyaya Syllogism

The school is particularly noted for its detailed analysis of inference. Unlike the three-membered Greek syllogism, the Nyaya system utilizes a five-membered structure that integrates both formal validity and material truth by requiring an illustrative example:3

1. Pratijna: Statement of the proposition to be proved.
2. Hetu: Statement of the reason.
3. Udaharana: Statement of a general rule supported by an example.
4. Upanaya: Application of the rule to the current case.
5. Nigamana: Drawing the final conclusion.3

By distinguishing between valid knowledge and invalid forms—such as doubt, error, and hypothetical argument—Nyaya established a foundational approach to systematic reasoning in Indian thought.1