Chapter 3.8 - Conclusion

Astika schools of Indian philosophy define Anumana as a process of knowing the truth not by direct observation but by means of knowledge of Vyapti. Nyaya system has defined inference as the knowledge of an object not by direct observation, but by means of the knowledge of the sign and symbol which has universal relationship with the objects of inference. It is an independent source of knowledge. It relates to objects which are of doubtful means or objects which have reason to believe but which have not yet been correctly corroborated. Gautama of the Nyaya Sutra has also held it by the same meaning as the system of Sankhya Yoga which states that Anumana is the knowledge taken from sign and signate. Gautama classifies inference into three: Purvavat (inference of effects from cause), Sheshavat (perceive the consequent and infer antecedent), and Samanyatodrista (provides knowledge of unperceived object). It has also been divided into two; Svarthanuamana (inference for oneself) and Pararthanumana (inference for others).

Inference involves five syllogisms, i.e.,

1. Pratijna or the proposition; the hill is on fire;
2. Hetu, or the reason; because it smokes;
3. Udaharana; or the explanatory example, whatever shows fire shows smoke, e.g. a kitchen;
4. Upanaya or the application; so is this hill, and
5. Nigamana, or the statement of the conclusion; therefore the hill is fiery.

There are different forms of inference i.e., inference starting from premises to conclusion and vice versa. In the Nyaya form of inference, the conclusion to be proved comes first and they call it as pratijna. The premises come last. This is the actual form of reasoning. It states that there must be two premises-the major and the minor and then there must be a third to synthesize these two. These three with conclusion and probandum provides the five-membered form of Nyaya syllogism of inference.