NyÃÂya (Sanskrit: à ¤¨à ¥Âà ¤¯à ¤¾à ¤¯à ¤Â, IAST: nyÃÂyaḥ), literally meaning "justice", "rules", "method" or "judgment", is one of the six orthodox (ÃÂstika) schools of Hindu philosophy. NyÃÂya's most significant contributions to Indian philosophy were the systematic development of the theory of logic, methodology, and its treatises on epistemology.
NyÃÂya epistemology accepts four out of six pramanas as reliable means of gaining knowledge â pratyaká¹£a (perception), anumÃÂá¹Âa (inference), upamÃÂna (comparison and analogy) and à Âabda (word, testimony of past or present reliable experts). In its metaphysics, NyÃÂya school is closer to the Vaisheshika school of Hinduism than others. It holds that human suffering results from mistakes/defects produced by activity under wrong knowledge (notions and ignorance). Moksha (liberation), it states, is gained through right knowledge. This premise led NyÃÂya to concern itself with epistemology, that is the reliable means to gain correct knowledge and to remove wrong notions. False knowledge is not merely ignorance to Naiyyayikas, it includes delusion. Correct knowledge is discovering and overcoming one's delusions, and understanding true nature of soul, self and reality.
Naiyyayika scholars approached philosophy as a form of direct realism, stating that anything that really exists is in principle humanly knowable. To them, correct knowledge and understanding is different from simple, reflexive cognition; it requires Anuvyavasaya (à ¤ à ¤¨à ¥Âà ¤µà ¥Âà ¤¯à ¤µà ¤¸à ¤¾à ¤¯, cross-examination of cognition, reflective cognition of what one thinks one knows). An influential collection of texts on logic and reason is the NyÃÂya Sà «tras, attributed to Aksapada Gautama, variously estimated to have been composed between 6th-century BCE and 2nd-century CE.
NyÃÂya school shares some of its methodology and human suffering foundations with Buddhism; however, a key difference between the two is that Buddhism believes that there is neither a soul nor self; NyÃÂya school like some other schools of Hinduism such as Dvaita and Vià Âiá¹£á¹ÂÃÂdvaita believes that there is a soul and self, with liberation (moká¹£a) as a state of removal of ignorance, wrong knowledge, the gain of correct knowledge, and unimpeded continuation of self.
Nyaya (à ¤¨à ¥Âà ¤¯à ¤¾à ¤¯) is a Sanskrit word which means justice, equality for all being, specially a collection of general or universal rules. In some contexts, it means model, axiom, plan, legal proceeding, judicial sentence, or judgment. Nyaya could also mean, "that which shows the way" tracing its Sanskrit etymology. In the theory of logic, and Indian texts discussing it, the term also refers to an argument consisting of an enthymeme or sometimes for any syllogism. In philosophical context, Nyaya encompasses propriety, logic and method.
Panini, revered Sanskrit grammarian, derives the "Nyaya" from the root "i" which conveys the same meaning as "gam" â to go. "Nyaya" signifying logic is there etymologically identical with "nigama" the conclusion of a syllogism.
Nyaya is related to several other concepts and words used in Indian philosophies: Hetu-vidya (science of causes), Anviksiki (science of inquiry, systematic philosophy), Pramana-sastra (epistemology, science of correct knowledge), Tattva-sastra (science of categories), Tarka-vidya (science of reasoning, innovation, synthesis), Vadartha (science of discussion) and Phakkika-sastra (science of uncovering sophism, fraud, error, finding fakes). Some of these subsume or deploy the tools of Nyaya.
The historical development of NyÃÂya school is unclear, although Nasadiya hymns of Book 10 Chapter 129 of Rigveda recite its spiritual questions in logical propositions. In early centuries BCE, states Clooney, the early NyÃÂya scholars began compiling the science of rational, coherent inquiry and pursuit of knowledge.
Aksapada Gautama composed the NyÃÂya Sà «tras (by 2nd century CE), a foundational text for NyÃÂya, that primarily discusses logic, methodology and epistemology. Gautama is also known as Aksapada and Dirghatapas. The names Gotama and Gautama points to the family to which he belonged while the names Aksapada and Dirghatapas refer respectively to his meditative habit and practice of long penance. The people of Mithila (modern Darbhanga in North Bihar) ascribe the foundation of NyÃÂya philosophy to Gautama, husband of Ahalya, and point out as the place of his birth a village named Gautamasthana where a fair is held every year on the 9th day of the lunar month of Chaitra (MarchâÂÂApril). It is situated 28 miles north-east of Darbhanga.
Concepts in the foundational text, the Nyaya Sutras, were clarified through a tradition of commentaries. Commentaries were also a means to defend the philosophy from misinterpretations by scholars of other traditions.
The NyÃÂya scholars that followed refined, expanded, and applied the Nyaya Sutras to spiritual questions. While the early Nyaya scholars published little to no analysis on whether supernatural power or God exists, they did apply their insights into reason and reliable means to knowledge to the questions of nature of existence, spirituality, happiness and moksha. Later NyÃÂya scholars, such as Udayana, examined various arguments on theism and attempted to prove existence of God. Other NyÃÂya scholars offered arguments to disprove the existence of God.
The most important contribution made by the NyÃÂya school to Hindu thought has been its treatises on epistemology and system of logic that, subsequently, has been adopted by the majority of the other Indian schools.
In the YÃÂjñavalkya Smá¹Âti, NyÃÂya is mentioned as one of the fourteen principal branches of learning. The Matsya-PurÃÂá¹Âa states that knowledge of NyÃÂya came from the mouth of BrahmÃÂ. The MahÃÂbhÃÂrata also mentions principles of NyÃÂya.
The earliest text of the NyÃÂya School is the ' of . The text is divided into five books, each having two sections. Vatsyayana's ' is a classic commentary on the '. Udyotakara's ' (6th century CE) is written to defend against the attacks made by DignÃÂga. 's ' (9th century CE) is the next major exposition of this school. Two other texts, ' and ' are also attributed to him. Udayana's (984 CE) ' is an important commentary on 's treatise. His ' is the first systematic account of theistic '. His other works include ', ' and '. Jayanta Bhatta's ' (10th century CE) is basically an independent work. Bhasarvajna's Nyayasara (10th century CE) is a survey of ' philosophy.
The later works on ' accepted the categories and 's ' (12th century CE) is a notable treatise of this syncretist school. 's ' (13th century CE) is another important work of this school.
's ' (14th century CE) is the first major treatise of the new school of '. His son, 's ', though a commentary on Udayana's ', incorporated his father's views. Jayadeva wrote a commentary on known as ' (14th century CE). 's ' (16th century CE) is first great work of Navadvipa school of . 's ' and ' are the next important works of this school. 's ' (17th century CE) is also a notable work. The Commentaries on ' by Jagadish Tarkalankar (17th century CE) and Gadadhar Bhattacharya (17th century CE) are the last two notable works of this school.
(17th century CE) tried to develop a consistent system by combining the ancient and the new schools, ' and ' and ' to develop the ' school. His ' and ' are the popular manuals of this school.
The NyÃÂya metaphysics recognizes sixteen padarthas or categories and includes all six (or seven) categories of the Vaisheshika in the second one of them, called prameya.
These sixteen categories are:
According to Matthew Dasti and Stephen Phillips, it may be useful to interpret the word jnana as cognition rather than knowledge when studying the NyÃÂya system.
Nyaya posits that there exists a self distinct from the mind, which is distinct from the body. The self is a nonphysical substance and is not inherently conscious.
The mind (manas) is postulated as a distinct entity because one can have two perceptions at the same time of the same object, through two different senses.
A cause is defined as an unconditional and invariable antecedent of an effect and an effect as an unconditional and invariable consequent of a cause. The same cause produces the same effect; and the same effect is produced by the same cause. The cause is not present in any hidden form whatsoever in its effect.
Nyaya recognizes three kinds of cause:
The following conditions should be met for something to be a cause:
Nyaya recognizes five kinds of accidental antecedents [Anyathasiddha]
NyÃÂya treatises on epistemology widely influenced other schools of Hinduism. 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." PramÃÂá¹Âa, 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. 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. By definition, pramÃÂá¹Âas are factive i.e. they cannot produce false belief. So, while statements can be false, testimony cannot be false.
NyÃÂya scholars accepted four valid means (pramÃÂá¹Âa) of obtaining valid knowledge (prameya) âÂÂ
The NyÃÂya 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 saá¹Âà Âaya (problems, inconsistencies, doubts) and viparyaya (contrariness, errors) which can be corrected or resolved by a systematic process of tarka (reasoning, technique).
Pratyaká¹£a (perception) occupies the foremost position in the NyÃÂya epistemology. Perception can be of two types, laukika (ordinary) and alaukika (extraordinary). Ordinary perception is defined by Aká¹£apÃÂda Gautama in his NyÃÂya 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: 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).
Ordinary perception to NyÃÂya scholars was based on direct experience of reality by eyes, ears, nose, touch and taste. 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).
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. All laukika and alaukika pratyakshas are savikalpa, but it is necessarily preceded by an earlier stage when it is indeterminate. VÃÂtsÃÂyana 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 PratyabhijñÃÂ, when one is able to re-recognise something on the basis of memory.
AnumÃÂna (inference) is one of the most important contributions of the NyÃÂya. 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 (Pararthanumana, 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.
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:
In NyÃÂya terminology for this example, the hill would be the paksha (minor term), the fire is the sÃÂdhya (major term), the smoke is hetu, and the relationship between the smoke and the fire is vyapti(middle term).
Hetu further has five characteristics
The fallacies in Anumana (hetvÃÂbhasa) may occur due to the following
UpamÃÂna (à ¤Âà ¤ªà ¤®à ¤¾à ¤¨) means comparison and analogy. UpamÃÂna, states Lochtefeld, may be explained with the example of a traveller who has never visited lands or islands with endemic population of wildlife. They are 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. The subject of comparison is formally called upameyam, the object of comparison is called upamÃÂnam, while the attribute(s) are identified as sÃÂmÃÂnya. Thus, explains Monier Williams, if a boy says "her face is like the moon in charmingness", "her face" is upameyam, the moon is upamÃÂnam, and charmingness is sÃÂmÃÂnya. The 7th century text Bhaá¹Âá¹ÂikÃÂvya 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. In various ancient and medieval texts of Hinduism, 32 types of UpamÃÂna and their value in epistemology are debated.
à Âabda (à ¤¶à ¤¬à ¥Âà ¤¦) means relying on word, testimony of past or present reliable experts. Hiriyanna explains Sabda-pramana as a concept which means testimony of a reliable and trustworthy person (ÃÂptavÃÂkya). 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. 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). The reliability of the source is important, and legitimate knowledge can only come from the Sabda of reliable sources. 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.
Testimony can be of two types, Vaidika (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.
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 phenomenological, causal, and logical organization of the world, playing a crucial role in the classification of objects.
Each school of Hinduism has its own treatises on epistemology, with different number of Pramanas. For example, compared to NyÃÂya school's four pramanas, Carvaka school has just one (perception), while Advaita Vedanta school recognizes six means to reliable knowledge.
According to the NaiyÃÂyikas, ordinary perception (where direct perception takes place) involves direct contact between sense organs and objects. In the case of illusory perception, the perceived object is not present in the locus of perception. To account for this, they propose the theory of "presentation through revived memory" (jñÃÂnalaká¹£aá¹ÂapratyÃÂsatti), where qualities known from past experience are projected onto what is presently seen. Thus, in the nacre-silver illusion, the shell is qualified by "silverness", not as a mental construction or a non-existent entity, but as silver existing elsewhere, and the means by which it is perceived without coming into contact with the sense organs is through jñÃÂnalaká¹£aá¹ÂapratyÃÂsatti.
NaiyÃÂyikas invoke JñÃÂnalaká¹£aá¹ÂapratyÃÂsatti to explain cases in which objects are perceived without direct contact between the senses and the object. Three examples of its application are commonly given:
In these examples, although there is no direct connection between the object and the sense organ, perception arises through the mediation of revived memory. For instance, the memory of sandalwood's fragrance is revived and projected onto the cognition of the sandalwood present at a distance. In the case of perceiving silver upon seeing nacre, the memory of silver influences the perception of nacre. The central idea is that past knowledge or experience can directly influence or shape present perception: the mind draws on revived memories and associates remembered qualities with the object being perceived to such an extent that it takes on the character of direct perception.
Early Naiyyayikas wrote very little about Ishvara (literally, the Supreme Soul). Evidence available suggests that early NyÃÂya scholars were non-theistic or atheists. Later, and over time, NyÃÂya scholars tried to apply some of their epistemological insights and methodology to the question: does God exist? Some offered arguments against and some in favor.
In NyÃÂya Sà «tra's Book 4, Chapter 1, verses 19âÂÂ21, postulates God exists, states a consequence, then presents contrary evidence, and from contradiction concludes that the postulate must be invalid.
A literal interpretation of the three verses suggests that NyÃÂya school rejected the need for a God for the efficacy of human activity. Since human action and results do not require assumption or need of the existence of God, sutra IV.1.21 is seen as a criticism of the "existence of God and theism postulate". The context of the above verses includes various efficient causes. NyÃÂya Sà «tra verses IV.1.22 to IV.1.24, for example, examine the hypothesis that "random chance" explains the world, after these Indian scholars had rejected God as the efficient cause.
In Nyayakusumanjali, Udayana gives the following nine arguments to prove the existence of creative God and also refutes the existing objections and questions by atheistic systems of Carvaka, Mimamsa, Buddhists, Jains and Samkhya:
Naiyyayikas characterize Ishvara as absent of adharma, false knowledge, and error; and possessing dharma, right knowledge, and equanimity. Additionally, Ishvara is omnipotent and acts in a way that is good for his creatures.
The Naiyyayikas believe that the bondage of the world is due to false knowledge, which can be removed by constantly thinking of its opposite (pratipakshabhavana), namely, the true knowledge. The opening aphorism of the ' states that only the true knowledge leads to niḥà Âreyasa (liberation). However, the NyÃÂya school also maintains that God's grace is essential for obtaining true knowledge. Jayanta, in his Nyayamanjari describes salvation as a passive stage of the self in its natural purity, unassociated with pleasure, pain, knowledge and willingness.
While initially distinct from Buddhism, NyÃÂya's rigorous approach to reasoning and epistemology profoundly influenced the development of Buddhist philosophy, particularly in the areas of logical analysis, epistemology, and the structure of doctrinal debates.
The influence of NyÃÂya on Buddhist epistemology is profound, especially in the development of the four major pramÃÂá¹Âa (valid means of knowledge). Below is a breakdown of how Buddhist thinkers integrated and adapted NyÃÂya concepts in their philosophical systems:
Another significant area of influence was in the domain of logic. NyÃÂya's formal system of inference (anumÃÂna) directly impacted Buddhist logic, especially in the works of scholars like Dharmakërti. NyÃÂya's focus on hetu (reasoning or cause) and the structure of valid arguments was adopted and modified by Buddhists in their development of logical proofs (pramÃÂá¹Âa) to support doctrines like impermanence and non-self.
In the PramÃÂá¹ÂavÃÂrttika, Dharmakërti reinterpreted NyÃÂyaâÂÂs logical tools to fit within Buddhist metaphysical views. For example, NyÃÂyaâÂÂs approach to inference was used to argue against essentialist doctrines by showing that all phenomena are dependent on causes and conditions (dependent origination), rather than existing inherently (svabhÃÂva). In MÃÂdhyamika philosophy, NÃÂgÃÂrjuna and à ÂÃÂntideva also employed logic and dialectical reasoning, heavily influenced by NyÃÂya, to argue against NyÃÂyaâÂÂs own concept of an unchanging self.
The formal practice of debate (yukti) in Buddhist scholasticism, especially within monastic institutions, reflects the influence of NyÃÂya. The rigorous techniques of formal reasoning and logical debate in NyÃÂya were adopted by Buddhists to engage in systematic argumentation, not only with other philosophical schools but also within their own traditions.
Buddhist monastic institutions, particularly in India, followed a debate structure built on NyÃÂyaâÂÂs epistemological principles, emphasizing the importance of valid reasoning and evidence in defending doctrinal views. These debates often centered around the validity of pramÃÂá¹Âas and the nature of reality (impermanence and non-self versus permanence and self). In Tibet and East Asia, these debates became central to the scholastic tradition and helped refine Buddhist thought over centuries.
Whilst NyÃÂya certainly influenced Buddhist philosophical arguments, it also openly criticised many of them. In his description of the nature of the Self, the NyÃÂya philosopher, UdÃÂyana, criticises the Buddhist no-self doctrine by arguing that it cannot be the case that the notion of a single entity is falsely superimposed upon successive cognitive events. UdÃÂyana's treatise on the nature of the Self, the Atmatattvaviveka, is also referred to as the Bauddha-dhikkÃÂra.
The related Buddhist doctrine of momentariness is also heavily criticised as being inconsistent with the real world actions of Buddhists, with NyÃÂya philosophers, for example, arguing why Buddhists teach the value of donation if they believe that everything is momentary. Such criticisms were not reserved only for metaphysics. NyÃÂya philosophers, such as Udyotakara, also criticised the Buddhist epistemological doctrine of apoha.
The impact of NyÃÂya was not confined to early Indian Buddhist thinkers but continued to shape later Buddhist traditions. For example, Tibetan Buddhism developed sophisticated methods of debate and logic that were heavily influenced by Indian NyÃÂya. In the Gelug school, the PramÃÂá¹Âa texts of Dharmakërti became a central part of the curriculum, alongside NyÃÂya texts.
In addition, Zen Buddhism and Chan Buddhism also exhibited traces of logical techniques influenced by the early scholastics of India, where rational discourse was used to sharpen the practitioner's understanding of emptiness (à Âà «nyatÃÂ) and impermanence.
B.K. Matilal, a renowned scholar of Indian philosophy, was instrumental in highlighting the intellectual connections between NyÃÂya and Buddhist epistemology. In his work, Matilal emphasizes how Buddhist philosophers like Dharmakërti incorporated and adapted NyÃÂyaâÂÂs logical frameworks to argue for impermanence and non-self. Matilal further discusses how Buddhists criticized NyÃÂyaâÂÂs essentialism, using formal logic and reasoning to refute NyÃÂya's claims about the permanence of the self and the inherent nature of things.
MatilalâÂÂs analysis of these philosophical interactions shows that, despite their doctrinal differences, NyÃÂya and Buddhism shared a common interest in developing systematic methods of reasoning and argumentation. His work underscores how both traditions engaged in a shared intellectual project of refining methods of knowledge acquisition and logical analysis, even as they differed on metaphysical views.
To illustrate the extent of NyÃÂyaâÂÂs influence on Buddhist philosophy, the following table highlights key concepts adopted and adapted by Buddhist scholars:
In addition to Dharmakërti and NÃÂgÃÂrjuna, Buddhist thinkers like Vasubandhu and à ÂÃÂntideva also utilized NyÃÂya-derived logic in their writings. Vasubandhu's work in the Abhidharma tradition integrated NyÃÂyaâÂÂs inference and perception frameworks to argue for emptiness and the illusion of permanence in all things.
Moreover, Tibetan Buddhist scholars like Chandrakirti and Jamyang Zhépa further developed these ideas, showing that the dialogue between NyÃÂya and Buddhism was not a one-way flow but rather an ongoing intellectual exchange that continued across centuries and geographical regions.
Numerous commentaries have been written on NyÃÂya-Sutra since its composition. A few of the commentaries are mentioned below:
Nyaya philosophy does not establish a category of a priori knowledge. This choice may be due to only considering de re knowledge, not de dicto knowledge.
The basic features of Western logic are: It deals with a study of âÂÂpropositionsâÂÂ, specially their âÂÂlogical formâ as abstracted from their âÂÂcontentâ or âÂÂmatterâÂÂ. It deals with âÂÂgeneral conditions of valid inferenceâÂÂ, wherein the truth or otherwise of the premises have no bearing on the âÂÂlogical soundness or validityâ of an inference. It achieves this by taking recourse to a symbolic language that has little to do with natural languages. The main concern of Western logic, in its entire course of development, has been one of systematising patterns of mathematical reasoning, with the mathematical objects being thought of as existing either in an independent ideal world or in a formal domain. Indian logic however, does not deal with ideal entities, such as propositions, logical truth as distinguished from material truth, or with purely symbolic languages that apparently have nothing to do with natural languages.
The central concern of Indian logic as founded in nyÃÂya is epistemology, or the theory of knowledge. Thus Indian logic is not concerned merely with making arguments in formal mathematics rigorous and precise, but attends to the much larger issue of providing rigour to the arguments encountered in natural sciences (including mathematics, which in Indian tradition has the attributes of a natural science and not that of a collection of context free formal statements), and in philosophical discourse. Inference in Indian logic is âÂÂdeductive and inductiveâÂÂ, âÂÂformal as well as materialâÂÂ. In essence, it is the method of scientific enquiry. Indian âÂÂformal logicâ is thus not âÂÂformalâÂÂ, in the sense generally understood: in Indian logic âÂÂformâ cannot be entirely separated from âÂÂcontentâÂÂ. In fact, great care is exercised to exclude from logical discourse terms, which have no referential content. No statement, which is known to be false, is admitted as a premise in a valid argument. Thus, the âÂÂmethod of indirect proofâ (reductio ad absurdum) is not accepted as a valid methodâÂÂneither in Indian philosophy nor in Indian mathematicsâÂÂfor proving the existence of an entity whose existence is not demonstrable (even in principle) by other (direct) means of proof.
Indian logic does not make any attempt to develop a purely symbolic and content independent or âÂÂformal languageâ as the vehicle of logical analysis. Instead, what Indian logic, especially in its later phase of Navya-NyÃÂya starting with the work of GÃÂngeà Âa UpÃÂdhyÃÂya of the 14th century, has developed is a technical language, which is based on the natural language Sanskrit, yet avoids âÂÂinexactnessâ and âÂÂmisleading irregularitiesâ by various technical devices. This technical language, being based on the natural language Sanskrit, inherits a certain natural structure and interpretation, and sensitivity to the context of enquiry. On the other hand, the symbolic formal systems of Western logic, though considerably influenced in their structure (say, in quantification, etc.) by the basic patterns discernible in European languages, are professedly purely symbolic, carrying no interpretation whatsoeverâÂÂsuch interpretations are supposed to be supplied separately in the specific context of the particular field of enquiry âÂÂemployingâ the symbolic formal system.
Departing from a traditional conceptualisation of knowledge, Timothy Williamson argues for a 'knowledge first' approach in which knowledge is not an occurrence of justified true belief. This approach parallels Nyaya epistemological arguments which suggest that knowledge is a 'non-composite' mental state.