Classical Indian Philosophy III: Nyāya and Vaiśeṣika

Nyāya and Vaiśeṣika are allied realist schools: Nyāya supplies the theory of knowledge and argument, Vaiśeṣika the inventory of what there is. The syllabus asks, for Nyāya, pramā and apramā, the four pramāṇas, the hetvābhāsas (fallacies of the reason), the concept of God, the debate with the Buddhists over pramāṇa-vyavasthā and pramāṇa-samplava, and anyathākhyāti; for Vaiśeṣika, the padārthas, asatkāryavāda, the three kinds of cause and the atomic theory of creation. This chapter works at the level of the sūtras and their classical commentators (Vātsyāyana, Uddyotakara, Vācaspati, Udayana, Gaṅgeśa, Praśastapāda). The Paper-1 aptitude chapters meet the pramāṇas and hetvābhāsas as reasoning tools; here they are part of a metaphysical system with its own debates. The document prints "upamana", "Hetvabhāsa" and "paramaṇukaraṇavāda"; the correct forms are upamāna, hetvābhāsa and paramāṇukāraṇavāda.

1. Pramā, apramā and the four pramāṇas

For Nyāya, pramā is a true cognition, "yathārtha anubhava", an experience that presents its object as it is. Memory (smṛti) is excluded because it is not a fresh experience, however accurate. Apramā covers doubt (saṃśaya), error (viparyaya) and hypothetical reasoning (tarka), which aids knowledge but is not itself knowledge. A pramāṇa is the special cause (karaṇa) of pramā. Nyāya counts four, where Cārvāka had one, Buddhism and Vaiśeṣika two, Sāṃkhya three, and Bhāṭṭa Mīmāṃsā and Advaita six.

The four Nyāya pramāṇas
PramāṇaDefinition and main divisions
Pratyakṣa (perception)Nyāya Sūtra 1.1.4: cognition produced by contact of sense and object, non-verbal (avyapadeśya), non-deviating (avyabhicāri) and determinate (vyavasāyātmaka). Later divided into nirvikalpaka (indeterminate) and savikalpaka (determinate); six kinds of sense-object contact (sannikarṣa); three extraordinary (alaukika) perceptions: sāmānyalakṣaṇa, jñānalakṣaṇa and yogaja
Anumāna (inference)Knowledge that follows another knowledge, resting on vyāpti. Old Nyāya: pūrvavat (cause to effect), śeṣavat (effect to cause), sāmānyatodṛṣṭa (from general correlation); svārtha (for oneself) and parārtha (for others, in five members); Navya-Nyāya: kevalānvayī, kevalavyatirekī, anvaya-vyatirekī
Upamāna (comparison)Knowledge of the relation between a name and what it names, gained through similarity: told that a gavaya (wild ox) is like a cow, one sees an animal like a cow in the forest and knows "this is a gavaya"
Śabda (testimony)The statement of a trustworthy person (āpta-vākya), worldly (laukika) or Vedic (vaidika); a sentence yields meaning when its words have expectancy (ākāṅkṣā), compatibility (yogyatā), proximity (sannidhi or āsatti) and, for later Nyāya, intended purport (tātparya)

The five-membered argument for others (parārthānumāna) runs: pratijñā (thesis: the hill has fire), hetu (reason: because it has smoke), udāharaṇa (example with the universal rule: whatever has smoke has fire, as a kitchen), upanaya (application: this hill has smoke, which is always accompanied by fire) and nigamana (conclusion: therefore the hill has fire). The hill is the pakṣa, fire the sādhya and smoke the hetu. A good hetu must be present in the pakṣa (pakṣadharmatā), present in similar cases (sapakṣa-sattva), absent from dissimilar cases (vipakṣa-asattva), not contradicted by stronger evidence (abādhitatva) and not countered by an equally strong reason (asatpratipakṣatva).

2. Hetvābhāsa: the five fallacies of the reason

A hetvābhāsa is a reason that looks like a reason but fails one of the five conditions above. Each classical fallacy corresponds to the failure of one condition, which is the easiest way to learn them. The Nyāya Sūtra (1.2.4) names them savyabhicāra, viruddha, prakaraṇasama, sādhyasama and kālātīta; later texts use the names in the second column.

The five hetvābhāsas
Sūtra nameLater nameDefectExample
SavyabhicāraAnaikāntika (inconclusive)Reason found also where the sādhya is absent (sādhāraṇa), or only in the pakṣa (asādhāraṇa), or with no non-pakṣa case to test (anupasaṃhārī)"The hill has fire because it is knowable"
ViruddhaViruddha (contradictory)Reason pervaded by the absence of the sādhya; it proves the opposite"Sound is eternal because it is produced"
PrakaraṇasamaSatpratipakṣa (counterbalanced)An equally strong reason proves the contrary"Sound is eternal because audible" against "non-eternal because produced"
SādhyasamaAsiddha (unestablished)The reason itself is unproved: of the locus (āśrayāsiddha), of its own nature (svarūpāsiddha), or of its pervasion (vyāpyatvāsiddha)"The sky-lotus is fragrant because it is a lotus"
KālātītaBādhita (contradicted)The sādhya is refuted by a stronger pramāṇa such as perception"Fire is cold because it is a substance"
⚠️ Prakaraṇasama is satpratipakṣa, not asiddha
The sūtra names mislead because "sama" appears twice. Prakaraṇasama is the counterbalanced reason (satpratipakṣa); sādhyasama is the unestablished reason (asiddha), so called because the reason stands as much in need of proof as the sādhya itself. Matching questions often swap the two.

3. God, the Buddhist debate and anyathākhyāti

Nyāya is theistic. God (Īśvara) is a special self, eternal, omniscient and free from karma, who is the efficient cause (nimitta-kāraṇa) of the world; the atoms are its material cause. Udayana's Nyāyakusumāñjali gives the classical proofs in one verse: from effects (kārya: the world, being made of parts, is an effect and needs an intelligent maker), from combination (āyojana: inert atoms need an agent to combine them at creation), from support (dhṛti: the world is held and in time dissolved), from the traditional arts and words (pada), from the authority of the Veda (pratyaya, śruti, vākya) and from the peculiar number (saṃkhyā-viśeṣa) that makes a dyad larger than its atoms. God is also the author of the Veda, which is why Nyāya grounds its authority in its author's reliability, unlike Mīmāṃsā.

Pramāṇa-vyavasthā against pramāṇa-samplava is a debate about whether each pramāṇa has its own exclusive object. The Buddhist logician Dignāga holds vyavasthā (fixed allocation): there are two kinds of object and so exactly two pramāṇas. Perception grasps only the unique particular (svalakṣaṇa), which is momentary and inexpressible; inference grasps only the universal (sāmānya-lakṣaṇa), which is a conceptual construction. Nyāya holds samplava (commingling): one and the same object can be known by several pramāṇas. Fire on a distant hill may be known first by testimony, then inferred from smoke, then perceived on arrival; Vātsyāyana uses such cases in his commentary on Nyāya Sūtra 1.1.3. For Nyāya the universal is real and perceivable, so there is no gulf between the object of perception and the object of inference.

Anyathākhyāti ("apprehension of something as otherwise") is the Nyāya theory of error. When shell is seen as silver, both terms are real: the shell is present before the eyes, and silver really exists elsewhere, in a shop or a mine. Through the similarity of shine, the memory of silver seen before presents it by extraordinary contact (jñānalakṣaṇa-pratyāsatti), and the cognition attributes silverness to the shell. Error is thus a real object misplaced, not an unreal one; it is discovered extrinsically, when the attempt to pick up the silver fails. That extrinsic test is the Nyāya doctrine of parataḥ-prāmāṇya: both the validity and the invalidity of a cognition are known from outside, by the success or failure of action (pravṛtti-sāmarthya).

🎯 Why the two debates are one debate
Samplava and anyathākhyāti both follow from Nyāya realism. If universals and relations are real features of the world, the same fire can be reached by perception and by inference, and an error can only be a real thing presented in the wrong place. The Buddhist who makes universals mental constructions must allocate pramāṇas to separate objects and must explain error as the mind projecting its own content.

4. Vaiśeṣika: the padārthas

Kaṇāda's Vaiśeṣika Sūtra and Praśastapāda's Padārthadharmasaṅgraha classify everything that can be known and named (padārtha, "meaning of a word") into six categories; abhāva (absence) was added as a seventh by later authors such as Śrīdhara, Udayana and Śivāditya, whose Saptapadārthī is named after the seven. The school takes its name from viśeṣa, the category that distinguishes it.

The seven padārthas
PadārthaContent
Dravya (substance)Nine: earth, water, fire, air, ākāśa, time (kāla), direction (dik), self (ātman) and mind (manas)
Guṇa (quality)Twenty-four in Praśastapāda (seventeen in the sūtra), including colour, taste, smell, touch, number, magnitude, cognition, pleasure, pain, desire, merit and demerit
Karma (motion)Five: throwing upward, throwing downward, contraction, expansion and going
Sāmānya (universal)Eternal, one, inhering in many; highest (para) is existence (sattā), lower (apara) ones such as potness
Viśeṣa (particularity)The ultimate individuator of eternal substances, such as one atom from another of the same kind
Samavāya (inherence)The eternal, inseparable relation of whole to parts, quality and motion to substance, universal to individual
Abhāva (absence)Prior (prāgabhāva), posterior or destruction (pradhvaṃsābhāva), absolute (atyantābhāva) and mutual (anyonyābhāva)

5. Asatkāryavāda, the three causes and the atomic theory

Against Sāṃkhya's satkāryavāda, Nyāya-Vaiśeṣika holds asatkāryavāda, also called ārambhavāda (the theory of new beginning): the effect does not exist in its cause before it is produced; it is a new whole (avayavī) that begins to exist. If the cloth already existed in the threads, weaving would be pointless and we could wear the threads. Every effect has three kinds of cause.

The three kinds of cause, for a cloth
CauseDefinitionExample
Samavāyi-kāraṇa (inherent)The substance in which the effect inheresThe threads
Asamavāyi-kāraṇa (non-inherent)A quality or motion inhering in the inherent cause that helps produce the effectThe conjunction of the threads; the colour of the threads for the colour of the cloth
Nimitta-kāraṇa (efficient)Any other cause that brings the effect aboutThe weaver, the loom and the shuttle

Paramāṇukāraṇavāda is the atomic theory of creation. Earth, water, fire and air exist in two forms: eternal atoms (paramāṇu), partless and imperceptible, and non-eternal composites. Ākāśa, time, direction, self and mind are eternal but not atomic. At creation two atoms combine into a dyad (dvyaṇuka), still imperceptible, and three dyads into a triad (tryaṇuka), the smallest perceptible magnitude, often likened to the mote seen in a sunbeam. The dyad's magnitude is produced by the number of its atoms, not their magnitude, since the atom's infinitesimal size (pārimāṇḍalya) cannot produce anything larger. Because atoms are inert, later Nyāya-Vaiśeṣika holds that their first motion is set going by the unseen merit of souls (adṛṣṭa) under God's will, which is where the āyojana proof of God comes from. Śaṅkara criticises the theory in his commentary on Brahma Sūtra 2.2.

Key takeaways

  • Pramā is yathārtha anubhava; memory, doubt, error and tarka are not pramā. Nyāya accepts four pramāṇas: perception (NS 1.1.4), inference (five members, five marks of a good hetu), comparison (gavaya) and testimony (ākāṅkṣā, yogyatā, sannidhi, tātparya).
  • Five hetvābhāsas: savyabhicāra (anaikāntika), viruddha, prakaraṇasama (satpratipakṣa), sādhyasama (asiddha), kālātīta (bādhita).
  • God is the efficient cause of the world (Udayana's proofs from effect, combination, support and the rest); Nyāya's samplava lets one object be known by many pramāṇas against Dignāga's vyavasthā of svalakṣaṇa to perception and sāmānya to inference.
  • Anyathākhyāti: error presents a real thing (silver elsewhere) in the wrong place through jñānalakṣaṇa contact; validity and invalidity are known parataḥ, by the success of action.
  • Vaiśeṣika: seven padārthas (nine dravyas, twenty-four guṇas, five karmas); asatkāryavāda; samavāyi, asamavāyi and nimitta causes; atoms of four elements combine into dyads and perceptible triads.

Practice questions (10)

Attempt each one before opening the answer. Every explanation names the tempting wrong option as well as the right one, because that is where marks are lost.

  1. Which theory of error is held by the Nyāya school?

    1. Satkhyāti
    2. Anyathākhyāti
    3. Anirvacanīyakhyāti
    4. Akhyāti
    Show answer

    Answer: B — Anyathākhyāti

    Nyāya holds anyathākhyāti: a real object is apprehended as otherwise than it is. Akhyāti is Prabhākara's, anirvacanīyakhyāti Advaita's and satkhyāti Rāmānuja's.

  2. In producing a cloth, the conjunction of the threads is the:

    1. Asamavāyi-kāraṇa
    2. Nimitta-kāraṇa
    3. Samavāyi-kāraṇa
    4. Upādāna in the Sāṃkhya sense
    Show answer

    Answer: A — Asamavāyi-kāraṇa

    The conjunction is a quality inhering in the threads that helps produce the cloth, so it is the non-inherent cause. The threads are the inherent cause and the weaver and loom the efficient causes.

  3. The hetvābhāsa called prakaraṇasama in the Nyāya Sūtra is known in later texts as:

    1. Asiddha
    2. Viruddha
    3. Satpratipakṣa
    4. Bādhita
    Show answer

    Answer: C — Satpratipakṣa

    Prakaraṇasama is the counterbalanced reason, where an equally strong reason proves the contrary: satpratipakṣa. Sādhyasama corresponds to asiddha and kālātīta to bādhita.

  4. Upamāna, as a pramāṇa in Nyāya, yields knowledge of:

    1. The relation between a name and the object it names, through similarity
    2. A fact assumed to explain another fact
    3. The absence of an object from a place
    4. The universal concomitance between smoke and fire
    Show answer

    Answer: A — The relation between a name and the object it names, through similarity

    Upamāna gives the knowledge that this animal is what "gavaya" names, using the told similarity to a cow. Knowledge of absence is anupalabdhi and postulation is arthāpatti, both accepted by Bhāṭṭa Mīmāṃsā, and vyāpti is grasped in inference.

  5. According to Nyāya-Vaiśeṣika, the magnitude of a dyad (dvyaṇuka) is produced by:

    1. The magnitude of its constituent atoms
    2. The conjunction of the dyad with ākāśa
    3. The will of God directly, without any quality of the atoms
    4. The number of its constituent atoms
    Show answer

    Answer: D — The number of its constituent atoms

    The atom's infinitesimal magnitude (pārimāṇḍalya) cannot produce a larger magnitude, so the dyad's magnitude is said to arise from number (saṃkhyā). This peculiarity is why Udayana lists saṃkhyā-viśeṣa among his proofs of God, since duality needs a cognising mind at creation.

  6. Assertion (A): Nyāya holds that the same object can be known by more than one pramāṇa. Reason (R): For Dignāga, perception grasps only the svalakṣaṇa and inference only the sāmānya-lakṣaṇa. Choose the correct option.

    1. Both A and R are true, and R is the correct explanation of A
    2. Both A and R are true, but R is not the correct explanation of A
    3. A is true, but R is false
    4. A is false, but R is true
    Show answer

    Answer: B — Both A and R are true, but R is not the correct explanation of A

    Both are true, but R states the Buddhist position of pramāṇa-vyavasthā, which Nyāya's samplava opposes; it cannot explain A. Nyāya's reason for samplava is that universals are real and perceivable, so the same fire can be heard of, inferred and seen.

  7. Assertion (A): Nyāya holds that the validity of a cognition is known parataḥ (extrinsically). Reason (R): A cognition is confirmed as valid by the success of the action it prompts. Choose the correct option.

    1. Both A and R are true, and R is the correct explanation of A
    2. Both A and R are true, but R is not the correct explanation of A
    3. A is true, but R is false
    4. A is false, but R is true
    Show answer

    Answer: A — Both A and R are true, and R is the correct explanation of A

    Both are true and R explains A: Nyāya's test of validity is pravṛtti-sāmarthya, the fruitfulness of action, which is an extrinsic check. Mīmāṃsā, by contrast, holds validity to be intrinsic (svataḥ).

  8. Which of the following substances have atoms (paramāṇu) according to Vaiśeṣika? Select all that apply.

    1. Fire
    2. Ākāśa
    3. Air
    4. Earth
    Show answer

    Answer: A — Fire; C — Air; D — Earth

    Only earth, water, fire and air are atomic. Ākāśa is eternal, one and all-pervading, so it has no atoms, and the same holds for time, direction, self and mind.

  9. Which of the following are conditions a sound hetu must satisfy in Nyāya? Select all that apply.

    1. Absence of an equally strong counter-reason
    2. Presence in the vipakṣa
    3. Presence in the pakṣa (pakṣadharmatā)
    4. Presence in the sapakṣa
    Show answer

    Answer: A — Absence of an equally strong counter-reason; C — Presence in the pakṣa (pakṣadharmatā); D — Presence in the sapakṣa

    A good hetu is in the pakṣa, in similar cases (sapakṣa), absent from dissimilar cases (vipakṣa), unrefuted and uncountered. Presence in the vipakṣa is precisely the defect of the inconclusive reason (savyabhicāra).

  10. How many dravyas (substances) does Vaiśeṣika recognise? Type the number.

    Numerical answer — type the value.

    Show answer

    Answer: 9

    Nine: earth, water, fire, air, ākāśa, time, direction, self and mind. The first four have atoms; the last five are eternal and non-atomic.