26  Indian Logic: Means of knowledge

26.1 What the Syllabus Covers

Indian Logic (Tarka-śāstra or Nyāya-śāstra) is the systematic study of valid knowledge and its means. It developed in parallel with Western logic but with a distinct vocabulary and a strong emphasis on epistemology — the means by which valid knowledge (pramā) is acquired.

The syllabus head asks the candidate to know the means of knowledge (pramāṇas) recognised by the principal Indian schools — Cārvāka, Buddhist, Jain, Sāṃkhya, Yoga, Nyāya, Vaiśeṣika, Mīmāṃsā, and Vedānta.

The PYQ patterns are: (a) name the six (or more) pramāṇas and match each to its school, (b) define valid knowledge (pramā) and its three other epistemic relatives (saṃśaya, viparyaya, smṛti), (c) identify which schools accept which pramāṇas, and (d) recognise the contributions of Gautama, Kaṇāda, Kumārila, Prabhākara, Śaṅkara.

26.2 Four Foundational Concepts

Every act of valid knowing involves four elements:

TipThe Four Epistemic Concepts
Sanskrit Translation Role
Pramā Valid knowledge What is produced
Pramātṛ Knower / cogniser The subject
Prameya Object of knowledge What is known
Pramāṇa Means of valid knowledge The instrument of knowing

A pramāṇa produces a pramā about a prameya for a pramātṛ.

26.2.1 Pramā and Its Three Counterparts

TipFour Types of Cognition
Sanskrit Translation What it is
Pramā Valid knowledge True cognition of an object
Saṃśaya Doubt Wavering between alternatives
Viparyaya / Bhrama Error / illusion False cognition (rope as snake)
Smṛti Memory Re-cognition of past experience (not counted as pramā by most schools)

26.3 The Six Classical Pramāṇas

The Mīmāṃsā school (especially the Bhāṭṭa branch of Kumārila) recognises six pramāṇas, the most comprehensive list. These six are the “vocabulary” within which every other school’s list is a subset.

TipThe Six Pramāṇas
# Pramāṇa Translation One-line meaning
1 Pratyakṣa Perception Direct cognition through the senses (or mind)
2 Anumāna Inference Knowledge from a known mark or sign (linga)
3 Upamāna Comparison / Analogy Knowledge of a new thing via similarity to a known thing
4 Śabda Verbal testimony Knowledge from a reliable / authoritative word
5 Arthāpatti Postulation / Presumption Inferring an unstated fact required to explain a known one
6 Anupalabdhi Non-apprehension Knowledge of absence by not perceiving 

flowchart TB
  P{The Six<br/>Pramāṇas} --> PR[Pratyakṣa<br/>Perception]
  P --> AN[Anumāna<br/>Inference]
  P --> UP[Upamāna<br/>Comparison]
  P --> SH[Śabda<br/>Testimony]
  P --> AR[Arthāpatti<br/>Postulation]
  P --> ANP[Anupalabdhi<br/>Non-apprehension]
    classDef default fill:#003366,color:#ffffff,stroke:#ffcc00,stroke-width:3px,rx:10px,ry:10px;

(Detailed coverage of each pramāṇa, with sub-types, appears in Topic 26.)

26.4 Pramāṇas Accepted by Each School

TipWhich School Accepts Which Pramāṇas
School Pramāṇas accepted Number
Cārvāka (Lokāyata) Pratyakṣa only 1
Buddhist (Vasubandhu, Dignāga, Dharmakīrti) Pratyakṣa, Anumāna 2
Vaiśeṣika (Kaṇāda) Pratyakṣa, Anumāna 2
Sāṃkhya (Kapila) Pratyakṣa, Anumāna, Śabda 3
Yoga (Patañjali) Pratyakṣa, Anumāna, Śabda 3
Nyāya (Gautama) Pratyakṣa, Anumāna, Upamāna, Śabda 4
Prābhākara Mīmāṃsā (Prabhākara) Pratyakṣa, Anumāna, Upamāna, Śabda, Arthāpatti 5
Bhāṭṭa Mīmāṃsā (Kumārila Bhaṭṭa) All six (adds Anupalabdhi) 6
Advaita Vedānta (Śaṅkara) All six 6
Jain (Pārśva, Mahāvīra) Three (Pratyakṣa, Parokṣa, Smṛti — different classification) special

26.4.1 A Quick Mnemonic for Numbers

TipSchool-Count Mnemonic

1 (Cārvāka) → 2 (Buddhists, Vaiśeṣika) → 3 (Sāṃkhya, Yoga) → 4 (Nyāya) → 5 (Prābhākara) → 6 (Bhāṭṭa, Advaita).

26.5 The Six Orthodox Schools — Quick Recap

TipThe Six Orthodox (Āstika) Schools
School Founder Core focus
Sāṃkhya Kapila Dualism: Puruṣa (consciousness) + Prakṛti (matter); 25 tattvas
Yoga Patañjali Practical Sāṃkhya; eight limbs (aṣṭāṅga yoga)
Nyāya Gautama (Akṣapāda) Logic, epistemology, 16 categories (padārtha)
Vaiśeṣika Kaṇāda Atomism, 7 categories of reality (padārtha)
Pūrva Mīmāṃsā Jaimini Vedic ritual & exegesis
Vedānta (Uttara Mīmāṃsā) Bādarāyaṇa; later Śaṅkara, Rāmānuja, Madhva Self & Brahman; many sub-schools
TipThe Three Heterodox (Nāstika) Schools
  • Cārvāka / Lokāyata — Materialism, denies karma, moksha, Veda. Accepts only Pratyakṣa.
  • Buddhism — Four Noble Truths, anātman. Accepts Pratyakṣa + Anumāna (Dignāga and Dharmakīrti’s school).
  • Jainism — Anekāntavāda (many-sided reality), Syādvāda (conditional predication), 5 great vows.

26.6 Cārvāka — One Pramāṇa Only

The Cārvāka (or Lokāyata) school accepts only Pratyakṣa — direct perception. They reject inference because inference depends on universal generalisation (vyāpti), which cannot itself be perceived. They reject verbal testimony as merely traditional belief.

TipCārvāka Position
  • Epistemology — Perception is the only valid means of knowledge.
  • Metaphysics — Only the material world; consciousness emerges from matter.
  • Ethics — Hedonism; pleasure is the highest goal.
  • Critique by other schools — If only perception is valid, even the claim “only perception is valid” cannot be perceived.

26.7 Buddhist Epistemology — Two Pramāṇas

Vasubandhu, Dignāga (5th–6th c. CE), and Dharmakīrti (7th c. CE) developed Buddhist logic. They accept:

TipBuddhist Pramāṇas
  • Pratyakṣa — perception (free of conceptual construction; nirvikalpa).
  • Anumāna — inference.

Dignāga’s Pramāṇa-samuccaya and Dharmakīrti’s Pramāṇa-vārttika are foundational texts. They classify inference as svārtha (for oneself) and parārtha (for others). Their school is often called Pramāṇavāda.

26.8 Vaiśeṣika — Two Pramāṇas (Kaṇāda)

Kaṇāda (also called Ulūka or Kāśyapa) founded Vaiśeṣika. Accepts Pratyakṣa and Anumāna; subsumes verbal testimony under inference. Famous for atomism: the universe is made of indivisible atoms (paramāṇu), eternal and indivisible.

26.9 Sāṃkhya and Yoga — Three Pramāṇas

Sāṃkhya (founder Kapila, Sāṃkhya-kārikā by Īśvarakṛṣṇa) and Yoga (Patañjali’s Yoga-sūtras) accept three pramāṇas:

TipSāṃkhya-Yoga Pramāṇas
  • Pratyakṣa — perception.
  • Anumāna — inference.
  • Śabda / Āpta-vacana — testimony of trustworthy persons (āpta = trustworthy / authoritative).

Sāṃkhya is the oldest of the six āstika schools. It is dualist — Puruṣa (consciousness) and Prakṛti (matter).

26.10 Nyāya — Four Pramāṇas (Gautama)

Gautama (Akṣapāda Gotama) in the Nyāya Sūtras (~2nd c. CE) gives the canonical list of four pramāṇas:

TipNyāya’s Four Pramāṇas
  1. Pratyakṣa — perception.
  2. Anumāna — inference.
  3. Upamāna — comparison / analogy.
  4. Śabda — testimony.

Nyāya is the school of logic par excellence. Its sixteen padārthas (categories) include pramāṇa, prameya, doubt, purpose, example, established tenet, syllogism (five-member), reasoning, decision, debate, wrangling, cavil, fallacy, quibble, futile rejoinder, point of defeat.

The five-member syllogism (pañcāvayava) is Nyāya’s distinctive contribution (see Topic 27):

TipNyāya’s Five-Member Syllogism

Pratijñā (proposition) → Hetu (reason) → Udāharaṇa (example) → Upanaya (application) → Nigamana (conclusion).

26.11 Mīmāṃsā — Five or Six Pramāṇas

Mīmāṃsā has two principal branches:

TipTwo Mīmāṃsā Branches
  • Prābhākara Mīmāṃsā (founder: Prabhākara Miśra) — Accepts five pramāṇas: the Nyāya four + Arthāpatti (postulation).
  • Bhāṭṭa Mīmāṃsā (founder: Kumārila Bhaṭṭa) — Accepts six pramāṇas: adds Anupalabdhi (non-apprehension) for cognition of absences.

26.12 Vedānta — Six Pramāṇas

Advaita Vedānta (Śaṅkara, ~8th c. CE) accepts all six Bhāṭṭa pramāṇas. Other Vedānta schools (Viśiṣṭādvaita of Rāmānuja, Dvaita of Madhva) recognise slightly different lists, typically three (perception, inference, testimony).

26.13 Jain Epistemology — A Special Classification

Jain epistemology classifies knowledge in a distinctive way:

TipJain Five-fold Knowledge
  1. Mati-jñāna — sensory knowledge (perception + ordinary cognition).
  2. Śruta-jñāna — knowledge from scripture / testimony.
  3. Avadhi-jñāna — clairvoyance.
  4. Manaḥ-paryāya-jñāna — telepathy.
  5. Kevala-jñāna — omniscience (perfect knowledge).

Jain logic uses Syādvāda (conditional predication — every proposition is true only conditionally; “in some respect”) and Anekāntavāda (many-sidedness of reality). Foundational figures: Mahāvīra, Umāsvāti, Hemacandra.

26.14 Indian Logic vs Western Logic — A Side-by-Side

TipIndian vs Western Logic
Dimension Indian (Nyāya) Western (Aristotle / modern)
Primary focus Epistemology + valid knowledge Formal validity of inference
Syllogism Five-member (pañcāvayava) Three-member (categorical)
Number of pramāṇas 1-6 (school-dependent) Often subsumes under perception + reason
Truth criterion Pramā (correspondence + utility) Correspondence; falsifiability
Fallacies Hetvābhāsa — fallacies of the inferential mark Formal + informal fallacies
Founder Gautama Aristotle
Earliest text Nyāya Sūtras (~2nd c. CE) Organon (4th c. BCE)

26.15 Theory Anchors

TipPersons, Texts, and Schools
Person Period Contribution
Kapila ancient Founder of Sāṃkhya
Patañjali ~2nd c. BCE / CE Yoga Sūtras; 8 limbs of Yoga
Kaṇāda ~6th c. BCE Founder of Vaiśeṣika; atomism
Gautama (Akṣapāda) ~2nd c. CE Nyāya Sūtras; 4 pramāṇas; 16 padārthas
Jaimini ancient Mīmāṃsā Sūtras
Bādarāyaṇa ancient Brahma Sūtras; Uttara Mīmāṃsā
Vasubandhu 4th–5th c. CE Buddhist logic
Dignāga 5th–6th c. CE Pramāṇa-samuccaya; Buddhist Pramāṇavāda
Dharmakīrti 7th c. CE Pramāṇa-vārttika
Kumārila Bhaṭṭa 7th–8th c. CE Bhāṭṭa Mīmāṃsā; 6 pramāṇas; Ślokavārttika
Prabhākara Miśra 7th–8th c. CE Prābhākara Mīmāṃsā; 5 pramāṇas
Śaṅkara ~788–820 CE Advaita Vedānta; Brahmasūtra Bhāṣya
Rāmānuja 11th–12th c. Viśiṣṭādvaita
Madhva 13th c. Dvaita
Bṛhaspati ancient (legendary) Founder of Cārvāka
Mahāvīra 6th c. BCE Jain reformer; 5 vows; Anekāntavāda
Umāsvāti ~2nd c. CE Tattvārtha Sūtra, Jain
Hemacandra 12th c. Jain logic, Pramāṇa Mīmāṃsā
Gaṅgeśa ~12th–13th c. Founder of Navya-Nyāya (New Nyāya); Tattva-cintāmaṇi

26.16 Practice Questions

Q 01 Concept Easy

In Indian logic, "pramāṇa" means:

  • AValid knowledge
  • BMeans of valid knowledge
  • CObject of knowledge
  • DKnower / subject
View solution
Correct Option: B
Pramāṇa = means / instrument of valid knowledge. Pramā = valid knowledge; Prameya = object; Pramātṛ = knower.
Q 02 Carvaka Easy

The Cārvāka school accepts how many pramāṇas?

  • AOne — Pratyakṣa only
  • BTwo
  • CFour
  • DSix
View solution
Correct Option: A
Pratyakṣa (perception) only. Cārvāka rejects inference and testimony.
Q 03 Nyaya Medium

The Nyāya school accepts how many pramāṇas?

  • ATwo
  • BThree
  • CFour
  • DSix
View solution
Correct Option: C
Nyāya's four: Pratyakṣa, Anumāna, Upamāna, Śabda.
Q 04 Match Hard

Match each school with the number of pramāṇas it accepts:

(i) Cārvāka (a) 4
(ii) Vaiśeṣika (b) 2
(iii) Nyāya (c) 6
(iv) Advaita Vedānta (d) 1
  • A(i)-d, (ii)-b, (iii)-a, (iv)-c
  • B(i)-a, (ii)-b, (iii)-c, (iv)-d
  • C(i)-c, (ii)-d, (iii)-a, (iv)-b
  • D(i)-b, (ii)-c, (iii)-d, (iv)-a
View solution
Correct Option: A
Cārvāka 1; Vaiśeṣika 2; Nyāya 4; Advaita Vedānta 6.
Q 05 Six Pramāṇas Medium

Which of the following is NOT one of the six classical pramāṇas?

  • APratyakṣa
  • BAnumāna
  • CSambhava
  • DAnupalabdhi
View solution
Correct Option: C
Six classical: Pratyakṣa, Anumāna, Upamāna, Śabda, Arthāpatti, Anupalabdhi. Sambhava (probability/inclusion) is sometimes recognised but is not in the standard six.
Q 06 Gautama Medium

The Nyāya Sūtras, foundational to Indian logic, were composed by:

  • AKapila
  • BGautama (Akṣapāda)
  • CKaṇāda
  • DPatañjali
View solution
Correct Option: B
Gautama (Akṣapāda), ~2nd c. CE.
Q 07 Vaisesika Medium

The founder of Vaiśeṣika, famous for atomism, is:

  • AGautama
  • BKapila
  • CKaṇāda
  • DJaimini
View solution
Correct Option: C
Kaṇāda (also Ulūka, Kāśyapa) — Vaiśeṣika and the atomic theory.
Q 08 Kumarila Hard

The pramāṇa "Anupalabdhi" (non-apprehension) was distinctively added by:

  • APrabhākara
  • BKumārila Bhaṭṭa
  • CŚaṅkara
  • DGautama
View solution
Correct Option: B
Kumārila Bhaṭṭa of the Bhāṭṭa Mīmāṃsā school. Prabhākara accepts 5 (without Anupalabdhi); Kumārila adds the 6th.
Q 09 Pramāṇa Name Medium

Knowledge of a new thing by similarity to a known thing is called:

  • APratyakṣa
  • BUpamāna
  • CŚabda
  • DArthāpatti
View solution
Correct Option: B
Upamāna = comparison / analogy.
Q 10 Sankhya Medium

Sāṃkhya and Yoga accept how many pramāṇas?

  • ATwo
  • BThree
  • CFour
  • DSix
View solution
Correct Option: B
Three: Pratyakṣa, Anumāna, Śabda (āpta-vacana).
Q 11 Buddhist Hard

Dignāga's *Pramāṇa-samuccaya* and Dharmakīrti's *Pramāṇa-vārttika* are foundational to:

  • AVedānta epistemology
  • BBuddhist logic (Pramāṇavāda)
  • CVaiśeṣika atomism
  • DJain Anekāntavāda
View solution
Correct Option: B
Dignāga (5th–6th c.) and Dharmakīrti (7th c.) — Buddhist logic. Buddhist Pramāṇavāda accepts only Pratyakṣa + Anumāna.
Q 12 Concepts Hard

Mistaking a rope for a snake is, in Indian epistemology, an example of:

  • APramā
  • BSaṃśaya
  • CViparyaya / Bhrama
  • DSmṛti
View solution
Correct Option: C
False cognition / illusion = Viparyaya / Bhrama. Used extensively in Advaita Vedānta's analysis of māyā.
Q 13 Sankhya Founder Medium

The traditional founder of the Sāṃkhya school is:

  • AKapila
  • BPatañjali
  • CKaṇāda
  • DJaimini
View solution
Correct Option: A
Kapila — oldest of the six āstika schools.
Q 14 Jain Hard

Jain logic is characterised by the doctrine of:

  • AAnekāntavāda (many-sided reality)
  • BAdvaita (non-dualism)
  • CAtomism only
  • DMaterialism
View solution
Correct Option: A
Anekāntavāda (many-sidedness) + Syādvāda (conditional predication). Reality has multiple aspects; each statement is only conditionally true.
Q 15 Nyaya 5 Steps Hard

In the Nyāya five-member syllogism, the second step is:

  • APratijñā (proposition)
  • BHetu (reason)
  • CUdāharaṇa (example)
  • DUpanaya (application)
View solution
Correct Option: B
Order: Pratijñā → Hetu → Udāharaṇa → Upanaya → Nigamana.
Q 16 Sankhya tattva Hard

Sāṃkhya philosophy is dualist; its two ultimate principles are:

  • ABrahman and Māyā
  • BPuruṣa and Prakṛti
  • CJīva and Karma
  • DForm and Matter
View solution
Correct Option: B
Puruṣa (consciousness) and Prakṛti (matter / nature). 25 tattvas evolve from their interaction.
Q 17 Prabhakara Hard

The Prābhākara Mīmāṃsā school accepts how many pramāṇas?

  • AThree
  • BFour
  • CFive
  • DSix
View solution
Correct Option: C
Five: Nyāya's four + Arthāpatti (postulation). Kumārila's Bhāṭṭa adds the sixth — Anupalabdhi.
Q 18 Jain Medium

In Jain epistemology, "kevala-jñāna" refers to:

  • ASensory knowledge
  • BScriptural knowledge
  • COmniscience / perfect knowledge
  • DTelepathy
View solution
Correct Option: C
Kevala-jñāna = perfect / omniscient knowledge — the highest of the five Jain types.
Q 19 Sankara Medium

Advaita Vedānta was systematised in the 8th century by:

  • ARāmānuja
  • BŚaṅkara
  • CMadhva
  • DVivekananda
View solution
Correct Option: B
Ādi Śaṅkara (~788–820 CE) — *Brahmasūtra Bhāṣya* and Advaita (non-dualism).
Q 20 Pramāṇa Identify Medium

"The room is empty" — knowing through *not* perceiving anything in the room — uses the pramāṇa called:

  • AUpamāna
  • BAnupalabdhi
  • CArthāpatti
  • DŚabda
View solution
Correct Option: B
Anupalabdhi = non-apprehension. Cognition of absence through the absence of perception.

26.17 Quick Recall

ImportantQuick recall
  • Four epistemic concepts: Pramā (valid knowledge) · Pramātṛ (knower) · Prameya (object) · Pramāṇa (means).
  • Four types of cognition: Pramā · Saṃśaya (doubt) · Viparyaya/Bhrama (error, e.g., rope-snake) · Smṛti (memory).
  • Six classical pramāṇas: Pratyakṣa · Anumāna · Upamāna · Śabda · Arthāpatti · Anupalabdhi.
  • Number by school: 1 Cārvāka (Pratyakṣa) · 2 Buddhist + Vaiśeṣika (Prat, Anum) · 3 Sāṃkhya + Yoga (+ Śabda) · 4 Nyāya (+ Upamāna) · 5 Prābhākara Mīmāṃsā (+ Arthāpatti) · 6 Bhāṭṭa Mīmāṃsā + Advaita Vedānta (+ Anupalabdhi).
  • 6 orthodox (āstika) schools: Sāṃkhya (Kapila) · Yoga (Patañjali) · Nyāya (Gautama) · Vaiśeṣika (Kaṇāda) · Pūrva Mīmāṃsā (Jaimini) · Vedānta (Bādarāyaṇa).
  • 3 heterodox (nāstika): Cārvāka (Bṛhaspati legendary) · Buddhism · Jainism.
  • Cārvāka = materialist + hedonist; perception only.
  • Buddhist Pramāṇavāda: Vasubandhu → Dignāga (5–6th c., Pramāṇa-samuccaya) → Dharmakīrti (7th c., Pramāṇa-vārttika). Svārtha vs Parārtha anumāna.
  • Vaiśeṣika (Kaṇāda) — atomism (paramāṇu); 7 padārthas.
  • Sāṃkhya (Kapila) — Puruṣa + Prakṛti, 25 tattvas. Yoga (Patañjali) — 8 limbs.
  • Nyāya (Gautama / Akṣapāda, Nyāya Sūtras ~2nd c. CE) — 16 padārthas; 5-step syllogism Pratijñā → Hetu → Udāharaṇa → Upanaya → Nigamana.
  • Mīmāṃsā: Pūrva = Jaimini (Vedic ritual); Bhāṭṭa (Kumārila, 6 pramāṇas) vs Prābhākara (5 pramāṇas).
  • Vedānta: Bādarāyaṇa → Śaṅkara (Advaita, ~800 CE) → Rāmānuja (Viśiṣṭādvaita, 11–12th c.) → Madhva (Dvaita, 13th c.).
  • Jain knowledge — 5 types: Mati · Śruta · Avadhi · Manaḥ-paryāya · Kevala (omniscience). Anekāntavāda + Syādvāda.
  • Navya-Nyāya (New Nyāya): Gaṅgeśa (~12–13th c.), Tattva-cintāmaṇi.
  • Indian vs Western logic: 5-member vs 3-member syllogism; epistemological vs purely formal focus; hetvābhāsa vs informal fallacies.