The Six Orthodox Systems: Sānkhya, Yoga, Nyāya, Vaiśeṣika, Mīmāṃsā and Vedānta
2. Nyāya and Vaiśeṣika: logic, categories and atomism
Nyāya (Gautama) is the school of logic and epistemology. It accepts four pramāṇas: pratyakṣa, anumāna, upamāna (comparison, knowing a thing from likeness to a known one) and śabda (reliable verbal testimony). Its inference is a five-membered syllogism — pratijñā (thesis), hetu (reason), udāharaṇa (example with the universal rule, vyāpti), upanaya (application) and nigamana (conclusion) — resting on vyāpti, the invariable concomitance of the reason with what is to be proved. A defective reason is a hetvābhāsa (fallacy).
- The five hetvābhāsas: savyabhicāra (the irregular reason, present also where the predicate is absent), viruddha (the contradictory reason, proving the opposite), satpratipakṣa (a reason counterbalanced by an equal opposing reason), asiddha (the unproved reason) and bādhita (the reason whose conclusion is contradicted by a stronger proof).
- Nyāya is theistic: God (Īśvara) is proved by inference as the intelligent efficient cause of the world — the world, being an effect (a product made of parts), needs an intelligent maker. God is the operative, not material, cause.
Nyāya holds asatkāryavāda (ārambhavāda): the effect does not pre-exist in its cause but is a genuinely new beginning — the cloth is a new whole (avayavī) over and above the threads. This directly opposes Sānkhya's satkāryavāda. Navya-Nyāya, the "new logic" founded by Gaṅgeśa (Tattvacintāmaṇi, c. 13th–14th century) and refined by Raghunātha Śiromaṇi, gave Indian logic a precise technical language for relations, negation and the limiting conditions (avacchedaka) of a cognition, without using symbols.
Vaiśeṣika (Kaṇāda), the sister school, is a pluralistic realism built on categories (padārthas): originally six — dravya (substance), guṇa (quality), karma (action), sāmānya (universal), viśeṣa (ultimate particularity, the source of the school's name) and samavāya (inherence) — with a seventh, abhāva (non-existence), added later. Its nine substances include the four elements, ākāśa, kāla, dik, ātman and manas. Its paramāṇuvāda (atomism) holds that earth, water, fire and air are built from eternal, partless atoms: two atoms make a dyad (dvyaṇuka) and three dyads a triad (tryaṇuka), the smallest visible thing. Vaiśeṣika accepts only two pramāṇas (perception and inference) and, with Nyāya, holds parataḥprāmāṇya — the validity of knowledge is extrinsic, established and known through external conditions.
3. Mīmāṃsā: dharma, apūrva, and Kumārila versus Prabhākara
Pūrva-Mīmāṃsā (Jaimini) is the philosophy of Vedic ritual and the interpretation of injunction. Its subject is dharma, defined as that which is known only through Vedic command (codanā) — the right ritual action. Because a sacrifice (yajña) is performed now but bears fruit later (for example heaven), Mīmāṃsā posits apūrva, an unseen potency created by the act that persists and yields the result at the proper time, bridging act and fruit. Later Mīmāṃsakas admit mokṣa, won by discharging the obligatory (nitya and naimittika) duties, avoiding the prohibited, and not undertaking desire-driven (kāmya) rites, so that karma is exhausted and rebirth ends.
The two Mīmāṃsā schools divide over the pramāṇas. Kumārila Bhaṭṭa (the Bhāṭṭa school) accepts six: pratyakṣa, anumāna, upamāna, śabda, arthāpatti (postulation — assuming a fact to explain what would otherwise be inexplicable, as "fat Devadatta eats nothing by day" implies he eats at night) and anupalabdhi (non-apprehension, the means by which we know a non-existence). Prabhākara (the Prābhākara school) accepts only five: he rejects anupalabdhi because he does not admit abhāva as a separate reality. Both schools hold svataḥprāmāṇya, the intrinsic validity of knowledge — every cognition is valid of itself, and only error is caused by extraneous defects.
Their theories of error also differ. Kumārila holds viparītakhyāti — a positive misapprehension in which the present object (the shell) is cognised as what it is not, a silver known from elsewhere being wrongly identified with it; this is a close kin of Nyāya's anyathākhyāti ("cognition otherwise"). The usual textbook split gives the name anyathākhyāti to Nyāya and viparītakhyāti to Kumārila; the syllabus heading lists anyathākhyāti under Mīmāṃsā, and some sources use that name for the Bhāṭṭa position as well, so read the two names as near-synonyms. Prabhākara holds akhyāti (vivekākhyāti) — there is strictly no false cognition at all; the shell is perceived, the silver is remembered, and error is only the failure to discriminate these two true cognitions and the mistaken action that follows.
4. Advaita Vedānta: Brahman, adhyāsa and māyā
Vedānta (Uttara-Mīmāṃsā) interprets the Upaniṣads, the Brahma-sūtra and the Gītā — the prasthāna-trayī. Śaṅkara's Advaita (non-dualism) holds that Brahman, pure being-consciousness-bliss (sat-cit-ānanda) and without qualities (nirguṇa), is the sole reality; the plural world is mithyā, a false appearance projected by māyā (avidyā), neither real nor unreal. The world is an apparent transformation of Brahman (vivartavāda), not a real one — unlike Sānkhya's pariṇāmavāda. In its standard exposition Advaita distinguishes three grades of reality: pāramārthika (absolute, Brahman), vyāvahārika (empirical, the workaday world) and prātibhāsika (illusory, the dream or the rope-snake).
The root of bondage is adhyāsa, superimposition: the beginningless mutual superimposition of the self and the not-self, so that one says "I am this body, this is mine." Īśvara is Brahman seen through māyā — saguṇa Brahman, the creator-God, real at the empirical level but not ultimate. The jīva (individual self) is Brahman delimited by the internal organ (antaḥkaraṇa): on the limitation view (avaccheda) like space enclosed in a pot, on the reflection view (pratibimba) like the sun mirrored in water. Ātman is Brahman — "tat tvam asi." Mokṣa is the removal of avidyā by direct knowledge (jñāna) of this identity, and may be attained while living (jīvanmukti).
On knowledge, Advaita follows the Bhāṭṭa list of six pramāṇas and holds svataḥprāmāṇya; but śabda (śruti) alone can reveal Brahman, since perception and inference reach only the empirical. Advaita's theory of error is anirvacanīyakhyāti — the illusory silver is indescribable (anirvacanīya), being neither real (it is sublated) nor unreal (it does appear); this same logic is extended to the world itself, which is why Advaita's model of ordinary illusion mirrors its account of cosmic appearance.
5. Viśiṣṭādvaita, Dvaita, Dvaitādvaita and Śuddhādvaita
Viśiṣṭādvaita (Rāmānuja) is qualified non-dualism: Brahman (Viṣṇu-Nārāyaṇa) is the sole reality but is qualified by the conscious selves (cit) and unconscious matter (acit), which form His body and are inseparable (apṛthak-siddhi) from Him. These are the tattva-traya — three reals: Īśvara, cit and acit. Souls and matter are real and eternal modes of Brahman, so the world is a real transformation of Brahman's body, not an illusion. Rāmānuja refutes Māyāvāda with his seven objections (sapta-vidha-anupapatti) — the Advaitin can give no coherent locus, nature, or means of removal for an avidyā that could obscure a self-luminous Brahman. Brahman is saguṇa, full of infinite auspicious qualities. Mokṣa is won by bhakti and prapatti (self-surrender) and by God's grace; the freed soul attains loving communion with God and keeps its individuality.
- Dvaita (Madhva) is thoroughgoing dualism. God (Viṣṇu) is independent (svatantra) and souls and matter are dependent (paratantra); there are five eternal differences (pañca-bheda): God–soul, God–matter, soul–soul, soul–matter and matter–matter. Souls are graded (tāratamya), and uniquely Madhva teaches that some souls are fit only for eternal bondage. Liberation is by God's grace, aided by bhakti and knowledge.
- Dvaitādvaita (Nimbārka), the bhedābheda or "difference-and-non-difference" view: the soul and the world are both different from and non-different from Brahman (Kṛṣṇa), as the sun's rays are to the sun — distinct yet inseparable. Three realities (cit, acit, Īśvara) are affirmed, and mokṣa comes through bhakti, prapatti and grace.
- Śuddhādvaita (Vallabha), "pure" non-dualism: Brahman (Kṛṣṇa) is pure (śuddha), free of any māyā, and the world and souls are real manifestations and parts (aṃśa) of Brahman, not illusory — hence "pure" as against Śaṅkara's advaita, which Vallabha reads as qualified by māyā. Liberation is by God's grace alone (puṣṭi-mārga, the path of grace) and loving devotion.
On knowledge, both Viśiṣṭādvaita and Dvaita accept three pramāṇas — pratyakṣa, anumāna and śabda (āgama). Rāmānuja's theory of error is satkhyāti (yathārthakhyāti): every cognition apprehends something real, for by the Upaniṣadic trebling of the elements (trivṛt-karaṇa) even the shell holds a real portion of the "silver" element, so the perception, though practically misleading, is of a real content. There is thus no cognition of the simply non-existent.
6. Comparing the schools: pramāṇas, causation and error
Three axes separate the orthodox schools cleanly and are the commonest exam ground: how many pramāṇas a school admits, whether it holds satkāryavāda or asatkāryavāda, and which khyātivāda (theory of error) it owns. The number of pramāṇas rises as a ladder, each school adding one means over the last.
| School | Number | Means accepted |
|---|---|---|
| Vaiśeṣika; Buddhism | 2 | Perception, inference |
| Sānkhya, Yoga; Viśiṣṭādvaita, Dvaita | 3 | + verbal testimony (śabda) |
| Nyāya | 4 | + comparison (upamāna) |
| Prābhākara Mīmāṃsā | 5 | + postulation (arthāpatti) |
| Bhāṭṭa Mīmāṃsā; Advaita | 6 | + non-apprehension (anupalabdhi) |
| Theory of error | School | Core idea |
|---|---|---|
| Anyathākhyāti | Nyāya-Vaiśeṣika | A real object elsewhere is apprehended as the "this" |
| Akhyāti | Prabhākara | No false cognition; only non-discrimination of two true ones |
| Viparītakhyāti | Kumārila (Bhāṭṭa) | A present object positively misapprehended as another (close kin of anyathākhyāti) |
| Anirvacanīyakhyāti | Advaita | The illusory content is indescribable, neither real nor unreal |
| Satkhyāti / yathārthakhyāti | Rāmānuja | Every cognition grasps a real content |
Key takeaways
- Sānkhya is a dualism of plural, inactive puruṣa and one unconscious prakṛti of three guṇas (sattva, rajas, tamas); it holds satkāryavāda (pariṇāma), three pramāṇas, and mokṣa as kaivalya by viveka. Yoga shares this, adds Īśvara as a special puruṣa, defines yoga as citta-vṛtti-nirodha, lists five kleśas and the eight limbs.
- Nyāya has four pramāṇas, a five-membered syllogism, five hetvābhāsas, a theistic inference for God, and asatkāryavāda; Navya-Nyāya (Gaṅgeśa) is its technical logic. Vaiśeṣika has the padārthas, atomism (paramāṇuvāda), two pramāṇas and, with Nyāya, parataḥprāmāṇya.
- Mīmāṃsā centres on dharma (Vedic injunction) and apūrva (the unseen link of act to fruit), holds svataḥprāmāṇya, and splits on pramāṇas — Kumārila six, Prabhākara five — and on error — Kumārila viparītakhyāti, Prabhākara akhyāti.
- Advaita: nirguṇa Brahman is the sole reality, the world is mithyā by māyā (vivartavāda), bondage is adhyāsa, Īśvara is saguṇa Brahman, Ātman is Brahman, mokṣa is jñāna, error is anirvacanīyakhyāti, with six pramāṇas and svataḥ validity.
- The other Vedāntas: Rāmānuja's Viśiṣṭādvaita (tattva-traya, body-of-God, refutation of māyāvāda, satkhyāti, mokṣa by bhakti), Madhva's Dvaita (five eternal differences, dependence on God), Nimbārka's Dvaitādvaita (bhedābheda) and Vallabha's Śuddhādvaita (pure non-dualism, real world, puṣṭi-mārga).
- Three axes decide most questions: pramāṇa count (2 up to 6), satkāryavāda (Sānkhya, Vedānta) versus asatkāryavāda (Nyāya-Vaiśeṣika), and the owner of each khyātivāda on the usual textbook split (anyathā = Nyāya, akhyāti = Prabhākara, viparīta = Kumārila, anirvacanīya = Advaita, satkhyāti = Rāmānuja).
Practice questions (16)
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.
In Sānkhya, prakṛti is constituted of three guṇas. Which triad names them?
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Answer: C — Sattva, rajas and tamas
Prakṛti is made of sattva (illumination), rajas (activity) and tamas (inertia); their disturbance from equilibrium starts evolution. Sat-cit-ānanda is Brahman's nature in Vedānta, dharma-artha-kāma are puruṣārthas, and mati-śruta-kevala are Jaina kinds of knowledge — none of these is the guṇa triad.On the Sānkhya view, mokṣa is kaivalya. Which statement captures what this liberation consists in?
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Answer: A — The isolation of puruṣa from prakṛti through the discriminative knowledge that the two are wholly distinct
Sānkhya is dualist and pluralist: liberation is kaivalya, the puruṣa's isolation from prakṛti through viveka, with no God and no merger. Merger into nirguṇa Brahman is Advaita; communion with a personal God by grace is Viśiṣṭādvaita; rising to the universe's summit after shedding karma is the Jaina account.Patañjali defines yoga as cittavṛttinirodha. What does this mean?
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Answer: B — The restraint or cessation of the modifications of the mind-stuff (citta)
Yoga is the stilling of the citta's vṛttis (modifications), after which consciousness rests in its own nature. Identity with Brahman is the Advaita goal, desireless action is the Gītā's karma-yoga, and the eightfold path is the Buddhist mārga — none is Patañjali's definition.In Patañjali's Yoga, which statement about Īśvara is correct?
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Answer: D — Īśvara is a special puruṣa untouched by afflictions, action and their residues, and is not the creator of the world
Yoga's Īśvara is a puruṣa-viśeṣa free of kleśas, karma and their residues, an object of devotion and aid to concentration — not a creator and not the material cause. Saguṇa Brahman as empirical creator is Advaita's Īśvara, the inference from the world-as-effect is the Nyāya proof, and prakṛti, not Īśvara, is the material cause that evolves.Which of the following statements about Yoga's kleśas and aṣṭāṅga are correct?
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Answer: A — Avidyā (ignorance) is the root kleśa from which the others spring; C — The last three limbs — dhāraṇā, dhyāna and samādhi — together form saṃyama
Avidyā is the root of the five kleśas, and dhāraṇā, dhyāna and samādhi (the last three limbs) together are saṃyama, the internal discipline. Prāṇāyāma is an external limb, not an internal one; and egoism is asmitā — abhiniveśa is the clinging to life or fear of death.How many pramāṇas does Nyāya accept, and what does it add to the three accepted by Sānkhya?
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Answer: A — Four — it adds upamāna (comparison) to perception, inference and testimony
Nyāya accepts four pramāṇas by adding upamāna to the Sānkhya three. Two is Vaiśeṣika, six is Bhāṭṭa Mīmāṃsā and Advaita, and five (arthāpatti added) is Prābhākara Mīmāṃsā.A thinker argues that a woven cloth is a genuinely new whole (avayavī), over and above the threads, which did not exist in the threads before weaving. This position, and the school that holds it, are:
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Answer: C — Asatkāryavāda (ārambhavāda), held by Nyāya-Vaiśeṣika
That the effect is a new beginning not latent in its cause is asatkāryavāda (ārambhavāda), the Nyāya-Vaiśeṣika doctrine. Satkāryavāda (Sānkhya) and vivartavāda (Advaita) both say the effect pre-exists; satkhyāti is a theory of error, not of causation, so it is a category mismatch.From which of its categories (padārthas) does the Vaiśeṣika school take its name?
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Answer: B — Viśeṣa, the ultimate particularity distinguishing one eternal atom from another
The school is named from viśeṣa, the ultimate particularity that distinguishes eternal atoms and selves from one another. Samavāya, sāmānya and dravya are also Vaiśeṣika categories, but none gives the school its name.In Vaiśeṣika atomism (paramāṇuvāda), which is the smallest perceptible composite?
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Answer: D — The triad (tryaṇuka), formed of three dyads
Atoms and dyads are supersensible; the triad (tryaṇuka, or trasareṇu), built from three dyads, is the smallest thing that can be perceived. Ākāśa is pervasive and not a product of atomic combination.Which of the following statements about Nyāya-Vaiśeṣika logic and epistemology are correct?
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Answer: A — A savyabhicāra reason is a fallacy because it is found also where the thing to be proved is absent; C — A viruddha reason is one that, instead of proving the thesis, establishes its contradictory
A savyabhicāra (irregular) reason strays to where the sādhya is absent, and a viruddha (contradictory) reason proves the opposite thesis — both genuine hetvābhāsas. Navya-Nyāya built a precise technical vocabulary but used no symbolic notation; and Nyāya-Vaiśeṣika holds parataḥprāmāṇya (extrinsic validity), not svataḥprāmāṇya.Which pramāṇa does Kumārila Bhaṭṭa accept that the Prābhākara school rejects?
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Answer: A — Anupalabdhi (non-apprehension)
Kumārila accepts six pramāṇas and Prabhākara five; the difference is anupalabdhi, which Prabhākara rejects because he does not admit abhāva (non-existence) as a separate reality. Arthāpatti, upamāna and śabda are accepted by both.In Mīmāṃsā, what is apūrva?
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Answer: B — An unseen potency produced by a sacrifice, which persists and yields the ritual's fruit at a later time
Apūrva is the unseen potency a ritual act creates, bridging the act now and its fruit (such as heaven) later. Superimposition is Advaita's adhyāsa, the store-consciousness is Yogācāra's ālaya-vijñāna, and the force moving atoms at creation is Vaiśeṣika's adṛṣṭa.On the Advaita view, the silver falsely seen in a piece of shell is best described as:
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Answer: C — Indescribable (anirvacanīya), being neither real, since it is later sublated, nor unreal, since it does appear
Advaita's anirvacanīyakhyāti makes the illusory silver indescribable — neither sat nor asat. Non-discrimination of two cognitions is Prabhākara's akhyāti, the real silver existing elsewhere is Nyāya's anyathākhyāti, and the shell holding a real silver-portion is Rāmānuja's satkhyāti.In Advaita Vedānta, the world's relation to Brahman is best described as:
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Answer: D — Vivarta, an apparent transformation in which Brahman only seems to become the world
Advaita holds vivartavāda: Brahman does not really change; the world is only its apparent appearance through māyā. Pariṇāma (real change) is Sānkhya's, ārambha is Nyāya-Vaiśeṣika's, and a real transformation of Brahman-with-its-body is Rāmānuja's view.Which of the following statements about the Vedānta schools are correct?
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Answer: A — Rāmānuja's Viśiṣṭādvaita affirms a tattva-traya of three reals: Īśvara, cit and acit; C — Vallabha's Śuddhādvaita treats the world as a real manifestation of Brahman, not as an illusion
Viśiṣṭādvaita's three reals are Īśvara, cit and acit, and Śuddhādvaita holds the world to be a real manifestation of Brahman. Madhva's five eternal differences include soul–soul difference and graded souls, so he does not deny it; and Advaita's mokṣa is the knowledge-born realisation of identity with nirguṇa Brahman, not communion with a personal God.Which of the following statements about Advaita's account of bondage and knowledge are correct?
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Answer: A — Adhyāsa is the beginningless mutual superimposition of the self and the not-self; B — On the pratibimba (reflection) view, the jīva is Brahman reflected in a limiting adjunct such as the internal organ
Adhyāsa is the beginningless superimposition at the root of bondage, and on the reflection theory the jīva is Brahman mirrored in a limiting adjunct such as the antaḥkaraṇa. The creator-God is saguṇa Īśvara, Brahman seen through māyā, not nirguṇa Brahman; and for Advaita śruti (śabda) is precisely the means that reveals Brahman, since perception and inference reach only the empirical.