---
type: Concept
bundle: nyaya-vaisheshika
bundle_version: 0.9.0
id: vyapti
title: Vyāpti
iast: Vyāpti
devanagari: व्याप्ति
description: Invariable concomitance, the pervasion 'wherever the mark, there the pervaded' that licenses every inference; established by repeated observation, co-absence, and tarka; NOT mere correlation, NOT material implication true by definition, NOT statistical association.
darshana:
- Nyāya
- Vaiśeṣika
text_source: Nyāya Bhāṣya on 1.1.5; Tattvacintāmaṇi, Vyāpti-vāda
tags:
- vyapti
- concomitance
- pervasion
- nyaya
- inference
not:
- term: correlation or observed co-occurrence
  why: 'A correlation records that two things have been seen together; vyāpti asserts that they cannot occur apart. The tradition is exacting about the gap: co-occurrence is the evidence, invariable concomitance is the claim, and moving from one to the other requires ruling out the vitiating condition (upādhi).'
  instead: State vyāpti as an exceptionless natural relation, 'no smoke without fire', not a frequency, and note that establishing it demands the absence of any upādhi that would make the tie conditional.
- term: material implication (if-then true by truth-values)
  why: Material implication holds by the assignment of truth-values and is indifferent to any real connection. Vyāpti is a tie in the world between properties; a merely true conditional with no real pervasion cannot warrant an inference in Nyāya.
- term: statistical association or high probability
  why: Vyāpti admits no exceptions. A property that usually accompanies another gives only a pseudo-mark (savyabhicāra, the deviating reason); the whole point of the concept is the difference between 'usually' and 'invariably'.
related:
- /concepts/anumana.md
- /concepts/hetu.md
- /concepts/tarka.md
- /concepts/hetvabhasa.md
timestamp: '2026-07-02'
okf_version: '0.2'
license: CC BY-SA 4.0
---

# Vyāpti -- व्याप्ति

**Not:** correlation, material implication, statistical association

## What It Actually Means

Vyāpti is the relation that makes a mark probative: the pervaded (vyāpya) is nowhere found without the pervader (vyāpaka), so smoke is pervaded by fire. Inference is only as sound as the vyāpti behind it, which is why Nyāya works hard to establish it: repeated positive observation, confirming co-presence; observation of co-absence, that removing the pervader removes the mark; and tarka, suppositional reasoning that shows the denial of the pervasion collapses into absurdity. The gravest threat is the upādhi, a hidden conditioning factor that makes the tie hold only under a further condition; detecting and excluding upādhis is the discipline that turns a mere generalization into a genuine pervasion. Navya-Nyāya later built an extraordinarily fine vocabulary for stating vyāpti precisely; that layer is deferred to a future bundle.

## Audience Metaphor

A weather app says it usually rains when the pressure drops: useful, but it will fail you. Vyāpti is a promise with no fine print: this sign never, ever comes without that outcome. The tradition spends its energy hunting the hidden clause (the upādhi) that would turn 'never' back into 'usually', because a single genuine exception voids the whole inference.

## Citations

1. Nyāya Sūtra 1.1.5 with Vātsyāyana's Bhāṣya -- see [references/nyaya-sutra.md](../references/nyaya-sutra.md)
2. Gaṅgeśa, Tattvacintāmaṇi, Vyāpti-vāda (the classic analysis; Navya-Nyāya refinement deferred) -- see [references/tattvacintamani.md](../references/tattvacintamani.md)
3. Annambhaṭṭa, Tarkasaṃgraha on vyāpti and upādhi -- see [references/tarkasamgraha.md](../references/tarkasamgraha.md)
