The Nyāya Sūtras

The Nyāya Sūtras, attributed to Gautama Akṣapāda, are the founding text of the Nyāya school and of the Indian tradition of logic and epistemology. Composed or compiled between about the second century BCE and the second century CE, they consist of roughly 530 short aphorisms in five books. Their subject is announced in their first sūtra: the highest good is attained through true knowledge of sixteen categories, beginning with the means of valid knowledge (pramāṇa) and the objects of knowledge (prameya), and continuing through the elements of reasoned argument to the forms of debate and its corruptions.

What the Sūtras say

The chain of suffering

The second sūtra gives the Nyāya theory of liberation in one sentence: “Suffering, birth, activity, faults and false knowledge — when each successive one is removed, the one before it is removed, and so liberation follows.” False knowledge — above all, mistaking the body for the self — produces faults (attachment, aversion, delusion); faults produce action; action produces birth; birth produces suffering. True knowledge cuts the root.

The means of knowledge

The Sūtras define perception as cognition from contact of sense and object that is non-verbal, non-erroneous and definite (1.1.4); inference as cognition preceded by perception, of three kinds — from cause to effect, effect to cause, and from common observation (1.1.5); comparison as knowledge of a thing through its similarity to a well-known thing (1.1.6); and testimony as the instruction of a reliable person (1.1.7). Book 2 defends these against a sceptic who argues that the means of knowledge cannot themselves be validated without regress: the Sūtras answer that a lamp illuminates itself as well as other things.

The five-membered argument

Book 1 sets out the five members of a public argument — thesis, reason, example, application and conclusion — and defines pseudo-reasons: the erratic, the contradictory, the counterbalanced, the unproved and the untimely. It distinguishes tarka, hypothetical or counterfactual reasoning (“if there were no fire, there would be no smoke”), which supports inference without itself being a means of knowledge.

Debate

The Sūtras define three forms of discussion: vāda, an honest exchange in which each side uses the means of knowledge and the five members to establish its view; jalpa, wrangling, which uses quibble, futile rejoinder and points of defeat to win; and vitaṇḍā, cavilling, which only attacks. Book 5 lists twenty-four kinds of futile rejoinder (jāti) and twenty-two points of defeat (nigrahasthāna) — among them abandoning one’s thesis, shifting the reason, irrelevance, meaningless talk, unintelligibility, incoherence, saying too little or too much, repetition, silence, ignorance, and evasion. Why should a philosopher study such tricks? “To protect the determination of truth, just as a fence of thorny branches protects the growth of seeds” (4.2.50).

The objects of knowledge

The twelve objects of knowledge that matter for liberation are the self, body, senses, sense-objects, cognition, mind, activity, faults, rebirth, fruit, suffering and liberation (1.1.9). Book 3 argues that the self is distinct from the body and senses, because we recognise with touch what we saw with the eyes, because desire depends on memory, and because a newborn’s smiles, fears and desire for the breast imply memories of past lives. It argues that the mind is atomic, since cognitions arise one at a time. Book 4 defends the reality of wholes against the Buddhist claim that only parts exist — if there were no wholes, we could not perceive anything, since atoms are imperceptible — and examines the nature of liberation.

Significance

The Sūtras are not elegant reading; they are lecture notes for a tradition. But they set the agenda of Indian epistemology for two thousand years: what counts as knowledge, how many means of knowing there are, how to argue honestly, and how to tell when an opponent is not.