27  Anumana: Structure, Vyapti and Hetvabhasas

Anumana — inference — is the second pramana, accepted by every Indian school except Charvaka. Indian inference, like Western syllogism, moves from known to unknown, but its structure has five members rather than three.

27.1 Vyapti — Universal Concomitance

The foundation of inference is vyapti — the invariable concomitance between the hetu (mark, reason) and the sadhya (the object to be inferred).

TipDefinition of Vyapti

Wherever there is smoke (hetu), there is fire (sadhya). The relation “wherever H, there S” is the vyapti.

Vyapti is established through repeated observation in many places (kitchen, hearth, forest fire) and the absence of counter-examples (no smoke without fire).

The classical example: smoke and fire. The kitchen is the sapaksha — the locus where both smoke and fire are known to co-occur — which establishes the vyapti.

27.2 Three Components of Inference

TipHetu, Sadhya, Paksha
Term Meaning In the smoke-fire example
Sadhya The thing to be inferred (probandum) Fire
Hetu / Linga The mark, reason, ground Smoke
Paksha The locus where the inference is made The hill

27.3 Pancha-Avayava — Five Members of Indian Inference

Nyaya formulates a complete inference in five steps (pancha-avayava). Buddhists later argued that three are sufficient.

TipFive Members (Pancha-Avayava)
Member Sanskrit Statement type Smoke-fire example
1. Pratijna Proposition Statement of what is to be proved The hill has fire
2. Hetu Reason Statement of the mark Because there is smoke
3. Udaharana Example Universal rule with example Wherever there is smoke there is fire, as in the kitchen
4. Upanaya Application Application to the present case This hill has smoke (which is invariably accompanied by fire)
5. Nigamana Conclusion Restatement of the proposition as proved Therefore, the hill has fire 

flowchart TB
  A[1. Pratijna<br/>The hill has fire] --> B[2. Hetu<br/>Because there is smoke]
  B --> C[3. Udaharana<br/>Wherever smoke, there fire — as in kitchen]
  C --> D[4. Upanaya<br/>This hill has smoke]
  D --> E[5. Nigamana<br/>Therefore, the hill has fire]
    classDef default fill:#003366,color:#ffffff,stroke:#ffcc00,stroke-width:3px,rx:10px,ry:10px;

TipWestern Syllogism vs Indian Pancha-Avayava
  • Western (Aristotelian): Major premise + Minor premise + Conclusion (3 members).
  • Indian (Nyaya): Pratijna + Hetu + Udaharana + Upanaya + Nigamana (5 members).
  • The Indian form has two extra members: a propositional statement at the start (pratijna) and an application step (upanaya). The udaharana includes both the universal rule and an example, while a Western syllogism’s major premise has only the rule.

27.4 Three Types of Anumana

Nyaya distinguishes three types of inference based on the relation between hetu and sadhya.

TipThree Types of Inference
Type Description Example
Purvavat Inferring the unperceived effect from a perceived cause (cause → effect) Seeing dark clouds → infer that it will rain
Sheshavat Inferring the unperceived cause from a perceived effect (effect → cause) Seeing a swollen river → infer that it has rained upstream
Samanyatodrshta Inferring through general correlation, where neither is the cause of the other Knowing that a man has reached the destination → because we know it takes time

A more recent classification distinguishes:

  • Svartha-anumana — for oneself; the inference one makes for one’s own sake.
  • Parartha-anumana — for others; the formal inference stated for another, requiring all five members.

27.5 Hetvabhasas — Fallacies of Inference

A hetvabhasa is a fallacious reason — a hetu that appears to be valid but is not. Nyaya identifies five major hetvabhasas.

TipFive Hetvabhasas (Fallacies of the Reason)
Fallacy Sanskrit Defect Example
Savyabhichara अनेकान्त The hetu is inconclusive — it occurs both with and without the sadhya Inferring “the hill is fiery” because “it is knowable” — but knowability accompanies many things, fiery and non-fiery
Viruddha विरुद्ध The hetu contradicts the sadhya — proves the opposite Inferring “sound is eternal because it is produced” — but being produced proves sound is non-eternal
Satpratipaksha सत्प्रतिपक्ष The hetu has an equally strong counter-hetu — neutralised Two equally good arguments lead to opposite conclusions
Asiddha असिद्ध The hetu is unestablished in the paksha Inferring fire because of smoke, when there is no smoke at the place
Badhita बाधित The hetu is contradicted by stronger evidence Inferring fire to be cold because of some property; but fire is directly perceived as hot 

flowchart TB
  H[Five Hetvabhasas] --> S[Savyabhichara<br/>Inconclusive]
  H --> V[Viruddha<br/>Contradictory]
  H --> SP[Satpratipaksha<br/>Counterbalanced]
  H --> A[Asiddha<br/>Unestablished]
  H --> B[Badhita<br/>Contradicted by stronger]
    classDef default fill:#003366,color:#ffffff,stroke:#ffcc00,stroke-width:3px,rx:10px,ry:10px;

27.6 Three Conditions of a Valid Hetu

For an inference to be valid, the hetu must satisfy three conditions (sometimes given as five in advanced texts).

TipThree Conditions
  1. Paksha-dharmata — the hetu must be present in the paksha (locus of inference).
  2. Sapaksha-sattva — the hetu must be present in similar instances (sapaksha) where the sadhya is known to occur.
  3. Vipaksha-asattva — the hetu must be absent from dissimilar instances (vipaksha) where the sadhya does not occur.

A hetu satisfying all three is called trairupya (three-fold). Two further conditions in some traditions (Buddhist Dignaga / Dharmakirti) bring the count to five.

27.7 Summary — Anumana Structure

TipAnumana — Working Vocabulary at a Glance
Term Meaning
Pramana Means of knowledge
Anumana Inference (the pramana of interest here)
Vyapti Universal concomitance — “wherever H, there S”
Hetu / Linga The mark / reason (e.g., smoke)
Sadhya The object inferred (e.g., fire)
Paksha The locus of inference (e.g., hill)
Sapaksha Similar instance (e.g., kitchen — has both smoke and fire)
Vipaksha Dissimilar instance (e.g., lake — has neither)
Pancha-avayava Five members of inference
Hetvabhasa Fallacious reason

27.8 Practice Questions

Q 01 Vyapti Easy

In Indian logic, the universal concomitance "wherever there is smoke, there is fire" is called:

  • AHetu
  • BSadhya
  • CVyapti
  • DPaksha
View solution
Correct Option: C
Vyapti = invariable concomitance between hetu (smoke) and sadhya (fire). It is the foundation of all inference.
Q 02 Components Medium

In the inference "The hill has fire because it has smoke", the term "fire" is the:

  • AHetu
  • BSadhya
  • CPaksha
  • DSapaksha
View solution
Correct Option: B
Fire is what is being inferred — the sadhya. Smoke is the hetu; the hill is the paksha.
Q 03 Pancha-Avayava Medium

A Nyaya inference (pancha-avayava) consists of how many members?

  • AThree
  • BFour
  • CFive
  • DSeven
View solution
Correct Option: C
Nyaya's pancha-avayava has five members: Pratijna, Hetu, Udaharana, Upanaya, Nigamana.
Q 04 Member Order Hard

Match each member of the pancha-avayava with its function:

(i) Pratijna (a) Universal rule with example
(ii) Hetu (b) Final conclusion
(iii) Udaharana (c) Initial proposition
(iv) Nigamana (d) Reason / mark
  • A(i)-(c), (ii)-(d), (iii)-(a), (iv)-(b)
  • B(i)-(a), (ii)-(b), (iii)-(c), (iv)-(d)
  • C(i)-(b), (ii)-(c), (iii)-(d), (iv)-(a)
  • D(i)-(d), (ii)-(a), (iii)-(b), (iv)-(c)
View solution
Correct Option: A
Pratijna → proposition; Hetu → reason; Udaharana → universal rule with example; Nigamana → conclusion.
Q 05 Hetvabhasas Hard

A hetu that is *inconclusive* — found both with and without the sadhya — commits the fallacy of:

  • AAsiddha
  • BSavyabhichara
  • CViruddha
  • DBadhita
View solution
Correct Option: B
Savyabhichara = inconclusive hetu — it accompanies both the sadhya and its absence.
Q 06 Types of Anumana Medium

Inferring that "it has rained upstream" from seeing a swollen river is an example of:

  • APurvavat
  • BSheshavat
  • CSamanyatodrshta
  • DSvartha
View solution
Correct Option: B
Sheshavat — inference from observed effect (swollen river) to unperceived cause (rain upstream). Purvavat is cause → effect.
Q 07 Conditions of Hetu Hard

"Vipaksha-asattva" — one of the conditions of a valid hetu — means that the hetu must:

  • ABe present in the paksha
  • BBe present in similar instances
  • CBe absent from dissimilar instances where the sadhya does not occur
  • DBe perceived directly
View solution
Correct Option: C
Vipaksha-asattva = absence of the hetu in dissimilar instances. Together with paksha-dharmata and sapaksha-sattva, this forms the trairupya.
Q 08 Svartha vs Parartha Medium

An inference made for the sake of others, requiring all five formal members, is called:

  • ASvartha-anumana
  • BParartha-anumana
  • CPurvavat
  • DSheshavat
View solution
Correct Option: B
Parartha-anumana = "for others"; requires the full pancha-avayava. Svartha-anumana = "for oneself".
ImportantQuick recall
  • Vyapti = universal concomitance (wherever H, there S).
  • Three components: Hetu (mark — smoke) · Sadhya (inferred — fire) · Paksha (locus — hill).
  • Pancha-avayava (5 members): Pratijna, Hetu, Udaharana, Upanaya, Nigamana.
  • Western syllogism = 3 members; Indian = 5 members.
  • Three types of anumana: Purvavat (cause→effect), Sheshavat (effect→cause), Samanyatodrshta (general correlation).
  • Two divisions: Svartha (for self) and Parartha (for others).
  • Five hetvabhasas: Savyabhichara, Viruddha, Satpratipaksha, Asiddha, Badhita.
  • Three conditions of a valid hetu (trairupya): paksha-dharmata, sapaksha-sattva, vipaksha-asattva.