Anumana

Anumana, in Sanskrit, denotes inference or deductive reasoning and is one of the classical pramanas (means of knowledge) in Indian philosophy, especially within the Nyaya school. It refers to knowledge gained about something not directly perceived by reasoning from a known general rule or observed relation between things that are known. In Nyaya, inference is considered a rational, evidence-based process used to derive new information from premises.

A standard Nyaya analysis of anumana uses a five-member syllogism: pratijna (the proposition to be established), hetu (the reason or middle term), udaharana or drstanta (an example that demonstrates the hetu’s reliability), upanaya (application of the example to the present case), and nigamana (the conclusion). The justification hinges on vyapti, the invariable concomitance between the hetu and the property to be known. In other words, wherever the hetu is present, the predicate is present, and in its presence the predicate can be inferred.

Typical structure and example: Pratijna: There is fire on the hill. Hetu: Smoke. Udaharana: Wherever there is smoke, there is fire (as in a kitchen). Upanaya: The hill has smoke, so it has fire. Nigamana: Therefore, there is fire on the hill. This framework allows inference about unseen states by relating them to observable or established relations.

Anumana has played a central role in Indian epistemology and logic, influencing subsequent Buddhist and Hindu thinkers. Critics have debated the conditions under which hetu and vyapti are reliable, leading to refined theories of inference and error analysis. In modern discussions, anumana is often equated with deductive reasoning or logical inference in a broader sense.