Editing Nyaya (section)

==Epistemology==
{{Philosophy sidebar|expanded=Traditions}}
[[File:4 Pramanas, epistemology according to ancient Nyayasutras.svg|thumb|The Nyaya school considers perception, inference, comparison/analogy, and testimony from reliable sources as four means to correct knowledge, holding that perception is the ultimate source of such knowledge.<ref name=jag/><ref name=gflood/>]]
Nyāya treatises on [[epistemology]] widely influenced other schools of Hinduism.<ref name="jalo" /> In Nyaya philosophy, knowledge is a type of "awareness event that is in accordance with its object by virtue of having been produced by a well-functioning epistemic instrument."<ref name=":1" /> ''Pramāṇa'', a Sanskrit word, literally is "means of knowledge". It encompasses one or more reliable and valid means by which human beings gain accurate, true knowledge.<ref name=jalo>James Lochtefeld, "Pramana" in The Illustrated Encyclopedia of Hinduism, Vol. 2: N-Z, Rosen Publishing. {{ISBN|0-8239-2287-1}}, pages 520–521</ref> The focus of Pramana is how correct knowledge can be acquired, how one knows, how one doesn't, and to what extent knowledge pertinent about someone or something can be acquired.<ref name="dpsb"/><ref name=kp>Karl Potter (2002), Presuppositions of India's Philosophies, Motilal Banarsidass, {{ISBN|81-208-0779-0}}, pages 25–26</ref> By definition, ''pramāṇas'' are factive i.e. they cannot produce false belief. So, while statements can be false, testimony cannot be false. <ref name=":1">{{Cite journal |last=Picascia |first=Rosanna |date=2023-04-18 |title=Our epistemic dependence on others: Nyāya and Buddhist accounts of testimony as a source of knowledge |url=https://academic.oup.com/jhs/article-abstract/17/1/62/7128281?redirectedFrom=fulltext |journal=Journal of Hindu Studies |volume=17 |issue=1 |pages=64 |doi=10.1093/jhs/hiad003 |issn=1756-4263}}</ref> 

Nyāya scholars accepted four valid means (''pramāṇa'') of obtaining valid knowledge (''prameya'') –

# perception (''pratyakṣa''), 
# inference (''anumāna''), 
# comparison (''[[upamāna]]''), and 
# word/testimony of reliable sources (''śabda'').

The Nyāya scholars, along with those from other schools of Hinduism, also developed a theory of error, to methodically establish means to identify errors and the process by which errors are made in human pursuit of knowledge. These include ''saṁśaya'' (problems, inconsistencies, doubts) and ''viparyaya'' (contrariness, errors)<ref>Karl Potter and Sibajiban Bhattacharya (1994), The Encyclopedia of Indian Philosophies, Volume 6, Princeton University Press, {{ISBN|978-0-691-07384-2}}, page 422</ref> which can be corrected or resolved by a systematic process of ''tarka'' (reasoning, technique).<ref>Karl Potter and Sibajiban Bhattacharya (1994), Logical Theory & Gangesa & Other chapters, in The Encyclopedia of Indian Philosophies, Volume 6, Princeton University Press, {{ISBN|978-0-691-07384-2}}, page 69-81, 178–201, 462–466</ref><ref>Gerald Larson and Ram Bhattacharya, The Encyclopedia of Indian Philosophies (Editor:Karl Potter), Volume 4, Princeton University Press, {{ISBN|978-0-691-07301-9}}, pages 361–362</ref>

===''Pratyaksha'' (perception)===
''Pratyakṣa'' (perception) occupies the foremost position in the ''Nyāya'' epistemology. Perception can be of two types, ''laukika'' (ordinary) and ''alaukika'' (extraordinary).<ref name=tror>Troy Organ, Philosophy and the Self: East and West, Associated University Presse, {{ISBN|978-0-941664-80-6}}, pages 91–94</ref> Ordinary perception is defined by Akṣapāda Gautama in his ''Nyāya Sutra'' (I, i.4) as a 'non-erroneous cognition which is produced by the intercourse of sense-organs with the objects'.

Indian texts identify four requirements for correct perception:<ref name=kpmat/> ''Indriyarthasannikarsa'' (direct experience by one's sensory organ(s) with the object, whatever is being studied), ''Avyapadesya'' (non-verbal; correct perception is not through [[hearsay]], according to ancient Indian scholars, where one's sensory organ relies on accepting or rejecting someone else's perception), ''Avyabhicara'' (does not wander; correct perception does not change, nor is it the result of deception because one's sensory organ or means of observation is drifting, defective, suspect) and ''Vyavasayatmaka'' (definite; correct perception excludes judgments of doubt, either because of one's failure to observe all the details, or because one is mixing inference with observation and observing what one wants to observe, or not observing what one does not want to observe).<ref name=kpmat>Karl Potter (1977), Meaning and Truth, in Encyclopedia of Indian Philosophies, Volume 2, Princeton University Press, Reprinted in 1995 by Motilal Banarsidass, {{ISBN|81-208-0309-4}}, pages 160–168</ref>

Ordinary perception to Nyāya scholars was based on direct experience of reality by eyes, ears, nose, touch and taste.<ref name=tror/> Extraordinary perception included ''yogaja'' or ''pratibha'' (intuition), ''samanyalaksanapratyaksa'' (a form of induction from perceived specifics to a universal), and ''jnanalaksanapratyaksa'' (a form of perception of prior processes and previous states of a 'topic of study' by observing its current state).<ref name=tror/><ref>Karl Potter (1977), Meaning and Truth, in Encyclopedia of Indian Philosophies, Volume 2, Princeton University Press, Reprinted in 1995 by Motilal Banarsidass, {{ISBN|81-208-0309-4}}, pages 168–169</ref>

====Determinate and indeterminate perception====
The Naiyyayika maintains two modes or stages in perception. The first is called ''[[nirvikalpa]]'' (indeterminate), when one just perceives an object without being able to know its features, and the second ''[[savikalpa]]'' (determinate), when one is able to clearly know an object.<ref>Karl Potter (1977), Meaning and Truth, in Encyclopedia of Indian Philosophies, Volume 2, Princeton University Press, Reprinted in 1995 by Motilal Banarsidass, {{ISBN|81-208-0309-4}}, pages 170–172</ref> All ''laukika'' and ''alaukika'' ''pratyakshas'' are ''savikalpa'', but it is necessarily preceded by an earlier stage when it is indeterminate. Vātsāyana says that if an object is perceived with its name we have determinate perception but if it is perceived without a name, we have indeterminate perception. [[Jayanta Bhatta]] says that indeterminate perception apprehends substance, qualities and actions and universals as separate and indistinct, without any association with any names, whereas determinate perception apprehends them all together with a name. There is yet another stage called ''Pratyabhijñā'', when one is able to re-recognise something on the basis of memory.<ref name=c>C Sharma, A Critical Survey of Indian Philosophy, Delhi: Motilal Banarsidass, {{ISBN|81-208-0365-5}}, pages192-196</ref>

===''Anumāna'' (inference)===
''Anumāna'' (inference) is one of the most important contributions of the Nyāya. It can be of two types: inference for oneself (''Svarthanumana'', where one does not need any formal procedure, and at the most the last three of their 5 steps), and inference for others (''Parathanumana'', which requires a systematic methodology of 5 steps). Inference can also be classified into 3 types: ''Purvavat'' (inferring an unperceived effect from a perceived cause), ''Sheshavat'' (inferring an unperceived cause from a perceived effect) and ''Samanyatodrishta'' (when inference is not based on causation but on uniformity of co-existence). A detailed analysis of error is also given, explaining when anumana could be false.<ref name=c/>

====Theory of inference====
The methodology of inference involves a combination of induction and deduction by moving from particular to particular via generality. It has five steps, as in the example shown:<ref>{{Citation |last=Dasti |first=Matthew R. |title=Nyāya |publisher=[[Internet Encyclopedia of Philosophy]] |url= https://iep.utm.edu/nyaya/ |access-date=2021-12-07 }}</ref><ref name="TS-AB">{{cite book |last1=Vidyasagara |first1=Pandit Jibananda |title=Tarkasangraha by Annabhatta |date=1872 |publisher=Sarasudhanidhi Press |location=Calcutta |page=24 |url=https://books.google.com/books?id=9bkIAAAAQAAJ |access-date=31 May 2022}}</ref>
* There is fire on the hill (called ''Pratijñā'', required to be proved)
* Because there is smoke there (called ''Hetu'', reason)
* Wherever there is smoke, there is fire, e.g. in a kitchen (called ''Udāhārana'', example of vyāpti)
* The hill has smoke that is pervaded by fire (called ''Upanaya'', reaffirmation or application)
* Therefore, there is fire on the hill (called ''Nigamana'', conclusion)

In Nyāya terminology for this example, the hill would be the ''paksha'' (minor term),<ref name="TS-AB"/>{{rp|31}} the fire is the ''sādhya'' (major term),<ref name="TS-AB"/>{{rp|21}} the smoke is ''hetu'',<ref name="TS-AB"/>{{rp|31}} and the relationship between the smoke and the fire is ''[[vyapti]]''(middle term).<ref name="TS-AB"/>{{rp|19}}

Hetu further has five characteristics<ref name="Matilal">{{cite book |last1=Matilal |first1=Bimal Krishna |title=Logic, Language and Reality: Indian Philosophies and Contemporary Issues |date=1 January 2008 |publisher=Motilal Banarsidass |location=Delhi |isbn=978-81-208-0008-3 |page=43 |edition=2nd |url=https://books.google.com/books?id=UkwvEAAAQBAJ |access-date=31 May 2022 |language=en}}</ref>

* It must be present in the ''Paksha'' (the case under consideration), 
* It must be present in all positive instances (''sapaksha'', or homologues),
* It must be absent in all negative instances
* It must not be incompatible with an established truth, (''abādhitatva'')
* Absence of another evidence for the opposite thesis (''asatpratipakshitva'')

==== Inference Fallacies (''hetvābhasa'') ====
The fallacies in Anumana (''hetvābhasa'') may occur due to the following<ref name="Jadunath">{{cite book |last1=Sinha |first1=Jadunath |title=Introduction to Indian Philosophy |date=1949 |publisher=Lakshmi Narain Agarwal |location=Agra |pages=53–58 |edition=1st |url=https://archive.org/details/in.ernet.dli.2015.17403/page/n63/mode/2up}}</ref>

#''Asiddha'': It is the unproved ''hetu'' that results in this fallacy.
#*''Ashrayasiddha'': If Paksha [minor term] itself is unreal, then there cannot be locus of the hetu. e.g. The sky-lotus is fragrant, because it is a lotus like any other lotus.
#*''Svarupasiddha'': Hetu cannot exist in paksa at all. E.g. Sound is a quality, because it is visible.
#*''Vyapyatvasiddha'': Conditional hetu. `Wherever there is fire, there is smoke'. The presence of smoke is due to wet fuel.
#''Savyabhichara'': This is the fallacy of irregular hetu.
#*''Sadharana'': The hetu is too wide. It is present in both sapaksa and vipaksa. `The hill has fire because it is knowable'.
#*''Asadharana'': The hetu is too narrow. It is only present in the Paksha, it is not present in the Sapaksa and in the Vipaksha. `Sound is eternal because it is audible'.
#*''Anupasamhari'': Here the hetu is non-exclusive. The hetu is all-inclusive and leaves nothing by way of sapaksha or vipaksha. e.g. 'All things are non-ternal, because they are knowable'.
#''Satpratipaksa'': Here the hetu is contradicted by another hetu. If both have equal force, then nothing follows. 'Sound is eternal, because it is audible', and 'Sound is non-eternal, because it is produced'. Here 'audible' is counterbalanced by 'produced' and both are of equal force.
#''Badhita'': When another proof (as by perception) definitely contradicts and disproves the middle term (hetu). 'Fire is cold because it is a substance'.
#''Viruddha'': Instead of proving something it is proving the opposite. 'Sound is eternal because it is produced'.

===''Upamāna'' (comparison, analogy)===
''Upamāna'' (उपमान) means comparison and analogy.<ref name=dpsb/><ref name="gflood"/> ''Upamāna'', states Lochtefeld,<ref name=jl721/> may be explained with the example of a traveller who has never visited lands or islands with endemic population of wildlife. He or she is told, by someone who has been there, that in those lands you see an animal that sort of looks like a cow, grazes like cow but is different from a cow in such and such way. Such use of analogy and comparison is, state the Indian epistemologists, a valid means of conditional knowledge, as it helps the traveller identify the new animal later.<ref name=jl721>James Lochtefeld, "Upamana" in The Illustrated Encyclopedia of Hinduism, Vol. 2: N-Z, Rosen Publishing. {{ISBN|0-8239-2287-1}}, page 721</ref> The subject of comparison is formally called ''upameyam'', the object of comparison is called ''upamānam'', while the attribute(s) are identified as ''sāmānya''.<ref name=mw457>Monier Williams (1893), Indian Wisdom – Religious, Philosophical and Ethical Doctrines of the Hindus, Luzac & Co, London, pages 457–458</ref> Thus, explains [[Monier Monier-Williams|Monier Williams]], if a boy says "her face is like the moon in charmingness", "her face" is ''upameyam'', the moon is ''upamānam'', and charmingness is ''sāmānya''. The  7th century text [[Bhaṭṭikāvya]] in verses 10.28 through 10.63 discusses many types of comparisons and analogies, identifying when this epistemic method is more useful and reliable, and when it is not.<ref name=mw457/> In various ancient and medieval texts of Hinduism, 32 types of ''Upamāna'' and their value in epistemology are debated.{{Citation needed|date=October 2024}}

===''Śabda'' (word, testimony)===
''Śabda'' (शब्द) means relying on word, testimony of past or present reliable experts.<ref name=dpsb/><ref name=eliottjag>
*Eliott Deutsche (2000), in Philosophy of Religion : Indian Philosophy Vol 4 (Editor: Roy Perrett), Routledge, {{ISBN|978-0-8153-3611-2}}, pages 245–248;
*John A. Grimes, A Concise Dictionary of Indian Philosophy: Sanskrit Terms Defined in English, State University of New York Press, {{ISBN|978-0-7914-3067-5}}, page 238</ref> Hiriyanna explains ''Sabda-pramana'' as a concept which means testimony of a reliable and trustworthy person (''āptavākya''). The schools of Hinduism which consider it epistemically valid suggest that a human being needs to know numerous facts, and with the limited time and energy available, he can learn only a fraction of those facts and truths directly.<ref name=mhir>M. Hiriyanna (2000), The Essentials of Indian Philosophy, Motilal Banarsidass, {{ISBN|978-81-208-1330-4}}, page 43</ref>  He must rely on others, his parent, family, friends, teachers, ancestors and kindred members of society to rapidly acquire and share knowledge and thereby enrich each other's lives. This means of gaining proper knowledge is either spoken or written, but through ''Sabda'' (words).<ref name=mhir/> The reliability of the source is important, and legitimate knowledge can only come from the ''Sabda'' of reliable sources.<ref name=eliottjag/><ref name=mhir/> The disagreement between the schools of Hinduism has been on how to establish reliability. Some schools, such as [[Carvaka]], state that this is never possible, and therefore ''Sabda'' is not a proper ''pramana''. Other schools debate means to establish reliability.<ref>P. Billimoria (1988), Śabdapramāṇa: Word and Knowledge, Studies of Classical India Volume 10, Springer, {{ISBN|978-94-010-7810-8}}, pages 1–30</ref>

Testimony can be of two types, ''Vaidika'' ([[Vedas|Vedic]]), which are the words of the four sacred Vedas, and ''Laukika'', or words and writings of trustworthy human beings. ''Vaidika'' testimony is preferred over ''Laukika'' testimony.  Laukika-sourced knowledge must be questioned and revised as more trustworthy knowledge becomes available.<ref name="SC-Nyaya">{{cite book |last1=Chatterjee |first1=Satischandra |title=The Nyaya Theory of Knowledge: A Critical Study of Some Problems of Logic and Metaphysics |date=1 January 2016 |publisher=Motilal Banarsidass |isbn=978-81-208-4082-9 |page=319 |url=https://books.google.com/books?id=N6b3DwAAQBAJ |access-date=31 May 2022 |language=en}}</ref><ref name="KLD-LnO">{{cite book |last1=Das |first1=Kanti Lal |last2=Mukherjee |first2=Anirban |title=Language and Ontology |date=2008 |publisher=Northern Book Centre |location=New Delhi |isbn=978-81-7211-228-8 |page=71 |url=https://books.google.com/books?id=CkG_SxiE4-AC |language=en}}</ref><ref name="Aphor-Gau">{{cite book |title=The Aphorisms of the Nyaya Philosophy by Gautama |date=1850 |publisher=Presbyterian Mission Press |location=Allahabad |page=51 |url=https://books.google.com/books?id=4C5Tsfe4bF4C |access-date=31 May 2022}}</ref>

=== Direct Realism ===
In Nyaya philosophy, direct realism asserts that our cognitions are informational states revealing external objects. According to Nyaya, the world consists of stable, three-dimensional objects, and their system of categories accurately mirrors reality's structure. Nyaya philosophy emphasizes the importance of universals, qualities, and relations in understanding the organization of the world. These foundational elements are believed to play essential roles in determining the [[Phenomenology (philosophy)|phenomenological]], causal, and logical organization of the world, playing a crucial role in the classification of objects.<ref>{{Cite book |last=Bartley |first=C. J. |title=An introduction to Indian philosophy |date=2011 |publisher=Continuum |isbn=978-1-84706-448-6 |location=London; New York |pages=91}}</ref>

===Comparison with other schools of Hinduism===
Each school of Hinduism has its own treatises on epistemology, with different number of ''[[Pramana]]s''. For example, compared to Nyāya school's four ''pramanas'', [[Carvaka]] school has just one (perception), while [[Advaita Vedanta]] school recognizes six means to reliable knowledge.<ref name="jag"/><ref name="eliottjag"/>