''Trairūpya (''Sanskrit; English: "the triple-character of inferential sign") is a conceptual tool of
Buddhist logic
Buddhist logico-epistemology is a term used in Western scholarship to describe Buddhism, Buddhist systems of ' (Epistemology, epistemic tool, valid cognition) and ' (reasoning, logic).
While the term may refer to various Buddhist systems and vi ...
. The Trairūpya, ‘three conditions’, is often accredited to
Dignaga (c. 480-540 CE) though is now understood to have originated with his teacher
Vasubandhu
Vasubandhu (; Tibetan: དབྱིག་གཉེན་ ; floruit, fl. 4th to 5th century CE) was an influential Indian bhikkhu, Buddhist monk and scholar. He was a philosopher who wrote commentary on the Abhidharma, from the perspectives of th ...
(fl. 4th century) in the ''Vāda-vidhi'', post-reconstruction of this work by
Frauwallner (1957).
Trairūpya is a logical argument that contains three constituents which a logical ‘sign’ or ‘mark’ (linga) must fulfill to be 'valid source of knowledge' (
pramana
''Pramana'' (; IAST: Pramāṇa) literally means " proof" and "means of knowledge". ):
#It should be present in the case or object under consideration, the ‘subject-locus' (pakṣa)
#It should be present in a ‘similar case’ or a homologue (sapakṣa)
#It should not be present in any ‘dissimilar case’ or heterologue (vipakṣa)
When a ‘sign’ or ‘mark’ (linga) is identified, there are three possibilities: the sign may be present in all, some, or none of the sapakṣas. Likewise, the sign may be present in all, some or none of the vipakṣas. To identify a sign, we have to assume that it is present in the pakṣa, however; that is the first condition is already satisfied. Combining these, Dignaga constructed his ‘Wheel of Reason’ (Sanskrit:
Hetucakra
''Hetucakra'' or ''Wheel of Reasons'' is a Sanskrit text on logic written by Dignaga (c 480–540 CE). It concerns the application of his 'three modes’ (trairūpya), conditions or aspects of the middle term called ''hetu'' ("reason" for a conc ...
).
[Ganeri, Jonardon & Tiwari, Heeraman (eds.), (1988). ''The Character of Logic in India''. Albany, NY, USA: State University of New York Press. (HC:acid free), p.7-8]
References
{{Indian Philosophy
History of logic
Buddhist logic