Buddhist logico-epistemology is a term used in Western scholarship to describe Buddhist systems of ' (epistemic tool, valid cognition) and ' (reasoning, logic).
While the term may refer to various Buddhist systems and views on reasoning and epistemology, it is most often used to refer to the work of the "Epistemological school" (Sanskrit: ), i.e., the school of Dignaga and Dharmakirti which developed from the 5th through 7th centuries and remained the main system of Buddhist reasoning until the decline of Buddhism in India.
The early Buddhist texts show that the historical Buddha was familiar with certain rules of reasoning used for debating purposes and made use of these against his opponents. He also seems to have held certain ideas about epistemology and reasoning, though he did not put forth a logico-epistemological system.
The Theravada KathÃÂvatthu contains some rules on debate and reasoning. The first Buddhist thinker to discuss logical and epistemic issues systematically was Vasubandhu in his VÃÂda-vidhi (A Method for Argumentation). A mature system of Buddhist logic and epistemology was founded by the Buddhist scholar DignÃÂga (âÂÂ540 CE) in his magnum opus, the PramÃÂá¹Âa-samuccaya. Dharmakirti further developed this system with several innovations in his Pramanavarttika ("Commentary on Valid Cognition"). His work was influential on all later Buddhist philosophical systems as well as on numerous Hindu thinkers. It also became the main source of epistemology and reasoning in Tibetan Buddhism.
Scholars such as H.N. Randle and Fyodor Shcherbatskoy (1930s) initially employed terms such as âÂÂIndian Logicâ and âÂÂBuddhist Logicâ to refer to the Indian tradition of inference (anumÃÂna), epistemology (pramana), and "science of causes" (hetu-vidyÃÂ). This tradition developed in the orthodox Hindu tradition known as Nyaya as well as in Buddhist philosophy. Logic in classical India, writes Bimal Krishna Matilal, is "the systematic study of informal inference-patterns, the rules of debate, the identification of sound inference vis-à-vis sophistical argument, and similar topics." As Matilal notes, this tradition developed out of systematic debate theory (vadavidyÃÂ):
<blockquote>Logic as the study of the form of correct arguments and inference patterns, developed in India from the methodology of philosophical debate. The art of conducting a philosophical debate was prevalent probably as early as the time of the Buddha and the Mahavira (Jina), but it became more systematic and methodical a few hundred years later.</blockquote>
"Indian Logic" is a different system than modern derivatives of classical logic (such as modern predicate calculus): anumÃÂna-theory, a system in its own right. "Indian Logic" was also influenced by the study of grammar, whereas Classical LogicâÂÂwhich principally informed modern Western LogicâÂÂwas influenced by the study of mathematics.
A key difference between Western Logic and Indian Logic is that certain epistemological issues are included within Indian Logic, whereas in modern Western Logic they are deliberately excluded. Indian Logic includes general questions regarding the "nature of the derivation of knowledge," epistemology, from information supplied by evidence, evidence which in turn may be another item of knowledge. For this reason, other scholars use the term "logico-epistemology" to refer to this tradition, emphasizing the centrality of the epistemic project for Indian logical reasoning. According to Georges Dreyfus, while Western logic tends to be focused on formal validity and deduction:
<blockquote>The concern of Indian "logicians" is quite different. They intend to provide a critical and systematic analysis of the diverse means of correct cognition that we use practically in our quest for knowledge. In this task, they discuss the nature and types of pramana. Although Indian philosophers disagree on the types of cognition that can be considered valid, most recognize perception and inference as valid. Within this context, which is mostly epistemological and practically oriented, topics such as the nature and types of correct reasoning that pertain to logic in the large sense of the word are discussed.</blockquote>
(Tib. ) is often translated as "valid cognition" or "instrument of knowledge" and refers to epistemic ways of knowing. Epistemological justification distinguishes Buddhist pramana from orthodox Hindu philosophy. All schools of Indian logic recognize various sets of "valid justifications for knowledge" or pramana. Buddhist logico-epistemology was influenced by the NyÃÂya school's methodology, but where the Nyaya recognised a set of four pramanasâÂÂperception, inference, comparison, and testimonyâÂÂthe Buddhists (i.e. the school of Dignaga) only recognized two: perception and inference. For Dignaga, comparison and testimony are just special forms of inference.
Most Indic pramanavada accept "perception" (Sanskrit: ) and "inference" (Sanskrit: ), but for some schools of orthodox Hinduism the "received textual tradition" (Sanskrit: ) is an epistemological category equal to perception and inference. The Buddhist logical tradition of Dignaga and Dharmakirti accept scriptural tradition only if it accords with and . This view is thus in line with the Buddha's injunction in the Kalama Sutta not to accept anything on mere tradition or scripture.
The time of the Gautama Buddha was a lively intellectual culture with many differing philosophical theories. KN Jayatilleke, in his "Early Buddhist Theory of Knowledge", uses the Pali Nikayas to glean the possible epistemological views of the historical Buddha and those of his contemporaries. According to his analysis of the Saá¹ gÃÂrava-sutta (AN 3.60), during the Buddha's time, Indian views were divided into three major camps with regards to knowledge:
The Buddha rejected the first view in several texts such as the Kalama sutta, arguing that a claim to scriptural authority (sadda) was not a source of knowledge, as was claimed by the later Hindu Mimamsa school. The Buddha also seems to have criticized those who used reason (takka). According to Jayatilleke, in the Pali Nikayas, this term refers "primarily to denote the reasoning that was employed to construct and defend metaphysical theories and perhaps meant the reasoning of sophists and dialecticians only in a secondary sense". The Buddha rejected metaphysical speculations, and put aside certain questions which he named the unanswerables (avyakatas), including questions about the soul and if the universe is eternal or not.
The Buddha's epistemological view has been a subject of debate among modern scholars. Some such as David Kalupahana, have seen him first and foremost as an empiricist because of his teaching that knowledge required verification through the six sense fields (ayatanas). The Kalama sutta states that verification through one's own personal experience (and the experiences of the wise) is an important means of knowledge.
However, the Buddha's view of truth was also based on the soteriological and therapeutic concern of ending suffering. In the "Discourse to Prince Abhaya" (MN.I.392âÂÂ4) the Buddha states that a belief should only be accepted if it leads to wholesome consequences. This has led scholars such as Mrs Rhys Davids and Vallée-Poussin to see the Buddha's view as a form of Pragmatism. This sense of truth as what is useful is also shown by the Buddha's parable of the arrow.
K. N. Jayatilleke sees Buddha's epistemological view as a kind of empiricism which also includes a particular view of causation (dependent origination): "inductive inferences in Buddhism are based on a theory of causation. These inferences are made on the data of perception. What is considered to constitute knowledge are direct inferences made on the basis of such perceptions." Jayatilleke argues the Buddhas statements in the Nikayas tacitly imply an adherence to some form of correspondence theory, this is most explicit in the Apannaka Sutta (MN 60). He also notes that Coherentism is also taken as a criterion for truth in the Nikayas, which contains many instances of the Buddha debating opponents by showing how they have contradicted themselves. He also notes that the Buddha seems to have held that utility and truth go hand in hand, and therefore something which is true is also useful (and vice versa, something false is not useful for ending suffering).
Echoing this view, Christian Coseru writes:
<blockquote>canonical sources make quite clear that several distinct factors play a crucial role in the acquisition of knowledge. These are variously identified with the testimony of sense experience, introspective or intuitive experience, inferences drawn from these two types of experience, and some form of coherentism, which demands that truth claims remain consistent across the entire corpus of doctrine. Thus, to the extent that Buddhists employ reason, they do so primarily in order further to advance the empirical investigation of phenomena.</blockquote>
The Early Buddhist Texts show that during this period many different kinds of philosophers often engaged in public debates (vivada). The early texts also mention that there was a set procedure (patipada) for these debates and that if someone does not abide by it they are unsuitable to be debated. There also seems to have been at least a basic conception of valid and invalid reasoning, including, according to Jayatilleke, fallacies (hetvabhasah) such as petitio principii. Various fallacies were further covered under what were called nigrahasthana or "reasons for censure" by which one could lose the debate. Other nigrahasthanas included arthantaram or "shifting the topic", and not giving a coherent reply.
According to Jayatilleke, 'pure reasoning' or 'a priori' reasoning is rejected by the Buddha as a source of knowledge. While reason could be useful in deliberation, it could not establish truth on its own.
In contrast to his opponents, the Buddha termed himself a defender of 'analysis' or vibhajjavada<nowiki/>'. He held that after proper rational analysis, assertions could be classified in the following way:
This view of analysis differed from that of the Jains, which held that all views were anekamsika and also were relative, that is, they were true or false depending on the standpoint one viewed it from (anekantavada).
The early texts also mention that the Buddha held there to be "four kinds of explanations of questions."
The Buddha also made use of various terms which reveal some of his views on meaning and language. For example, he held that many concepts or designations (paññatti) could be used in conventional everyday speech while at the same time not referring to anything that exists ultimately (such as the pronouns like "I" and "Me"). Richard Hayes likewise points to the Potthapada sutta as an example of the Early Buddhist tendency towards a nominalist perspective on language and meaning in contrast to the Brahmanical view which tended to see language as reflecting real existents.
The Buddha also divided statements (bhasitam) into two types with regards to their meaning: those which were intelligible, meaningful (sappatihirakatam) and those meaningless or incomprehensible (appatihirakatam). According to Jayatilleke, "in the Nikayas it is considered meaningless to make a statement unless the speaker could attach a verifiable content to each of its terms." This is why the Buddha held that statements about the existence of a self or soul (atman) were ultimately meaningless, because they could not be verified.
The Buddha, like his contemporaries, also made use of the "four corners" (catuá¹£koá¹Âi) logical structure as a tool in argumentation. According to Jayatilleke, these "four forms of predication" can be rendered thus:
The Buddha in the Nikayas seems to regard these as "'the four possible positions or logical alternatives that a proposition can take". Jayatilleke notes that the last two are clearly non-Aristotelian in nature. The Buddhists in the Nikayas use this logical structure to analyze the truth of statements and classify them. When all four were denied regarding a statement or question, it was held to be meaningless and thus set aside or rejected (but not negated).
The early texts mention two modes of discourse used by the Buddha. Jayatilleke writes:
<blockquote>when he is speaking about things or persons we should not presume that he is speaking about entities or substances; to this extent his meaning is to be inferred (neyyattha-). But when he is pointing out the misleading implications of speech or using language without these implications, his meaning is plain and direct and nothing is to be inferred (nitattha-). This is a valid distinction which certainly holds good for the Nikäyas at least, in the light of the above-statement.</blockquote>
The later commentarial and Abhidharma literature began to use this distinction as an epistemic one. They spoke of two levels of truth, the conventional (samutti), and the absolute (paramattha). This theory of double truth became very influential in later Buddhist epistemic discourse.
The Theravada KathÃÂvatthu (Points of Controversy) is a Pali Buddhist text which discusses the proper method for critical discussions on doctrine. Its date is debated by scholars but it might date to the time of Ashoka (C. 240 BC). Western scholarship by St. Schayer and following him A. K. Warder, have argued that there is an "anticipations of propositional logic" in the text. However, according to Jonardon Ganeri "the leading concern of the text is with issues of balance and fairness in the conduct of a dialogue and it recommends a strategy of argumentation which guarantees that both parties to a point of controversy have their arguments properly weighed and considered."
In the KathÃÂvatthu, a proper reasoned dialogue (vadayutti) is structured as follows: there is a point of contention â whether A is B; this is divided into several 'openings' (atthamukha):
These help clarify the attitude of someone towards their thesis in the proceeding argumentative process. Jonardon Ganeri outlines the process thus:
<blockquote>Each such âÂÂopeningâ now proceeds as an independent dialogue, and each is divided into five stages: the way forward (anuloma), the way back (patikamma), the refutation (niggaha), the application (upanayana) and the conclusion (niggamana). In the way forward, the proponent solicits from the respondent the endorsement of a thesis and then tries to argue against it. On the way back, the respondent turns the tables, soliciting from the proponent the endorsement of the counter-thesis, and then trying argue against it. In the refutation, the respondent, continuing, seeks to refute the argument that the proponent had advanced against the thesis. The application and conclusion repeat and reaffirm that the proponentâÂÂs argument against the respondentâÂÂs thesis is unsound, while the respondentâÂÂs argument against the proponentâÂÂs counter-thesis is sound.</blockquote>
Another Buddhist text which depicts the standards for rational debate among Buddhists is the Milindapanha ("Questions of Menander", 1st century BCE) which is a dialogue between the Buddhist monk Nagasena and an Indo-Greek King. In describing the art of debate and dialogue, Nagasena states:
<blockquote>When scholars talk a matter over one with another, then is there a winding up, an unravelling, one or other is convicted of error, and he then acknowledges his mistake; distinctions are drawn, and contra-distinctions; and yet thereby they are not angered.</blockquote>
The various elements outlined here make up the standard procedure of Buddhist debate theory. There is an 'unravelling' or explication (nibbethanam) of one's thesis and stances and then there is also a 'winding up' ending in the censure (niggaho) of one side based on premises he has accepted and the rejoinders of his opponent.
The Buddhist Abhidharma schools developed a classification of four types of reasoning which became widely used in Buddhist thought. The Mahayana philosopher Asanga in his Abhidharma-samuccaya, outlines these four reasons (yukti) that one may use to inquire about the nature of things. According to Cristian Coseru these are:
According to Coseru "what we have here are examples of natural reasoning or of reasoning from experience, rather than attempts to use deliberative modes of reasoning for the purpose of justifying a given thesis or arguing for its conditions of satisfaction."
The NyÃÂya Sà «tras of Gotama (6th century BC â 2nd century CE) is the founding text of the Nyaya school. The text systematically lays out logical rules for argumentation in the form of a five-step schema and also sets forth a theory of epistemology. According to Jonardon Ganeri, the Nyaya sutra brought about a transformation in Indian thinking about logic. First, it began a shift away from interest in argumentation and debate towards the formal properties of sound inference. Secondly, the Nyaya sutra led a shift to rule-governed forms of logical thinking.
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 NyÃÂya's logical tools to fit within Buddhist metaphysical views. For example, NyÃÂya's 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 NyÃÂya's 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.
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.
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 NyÃÂya's 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.
B.K. Matilal outlines the five steps or limbs of the Nyaya method of reasoning as follows:
Later Buddhist thinkers like Vasubandhu would see several of these steps as redundant and would affirm that only the first two or three were necessary.
The Naiyayikas (the Nyaya scholars) also accepted four valid means (pramaá¹Âa) of obtaining valid knowledge (pramana) - perception (pratyaká¹£a), inference (anumÃÂna), comparison (upamÃÂna) and word/testimony of reliable sources (à Âabda).
The systematic discussions of the Nyaya school influenced the Medieval Buddhist philosophers who developed their own theories of inferential reasoning and epistemic warrant (pramana). The Nyaya became one of the main opponents of the Buddhists.
While the direct influence of the Vaià Âeá¹£ika school on Buddhism was limited compared to that of the NyÃÂya school, certain concepts from Vaià Âeá¹£ika philosophy did inform or prompt responses within Buddhist thought, particularly in the context of Atomism, metaphysics, and conceptual classification. The influence was often indirect, occurring through shared intellectual debates and through the later fusion of NyÃÂya and Vaià Âeá¹£ika into a combined tradition.
The Vaià Âeá¹£ika school, traditionally attributed to the sage Kaá¹ÂÃÂda, emerged around the 2nd century BCE and developed a detailed realist metaphysical system centered on the analysis of substances, qualities, motion, and universals. While Buddhist traditions primarily emphasized ethical practice, meditation, and liberation from suffering, by the time of the Abhidharma scholastic period, Buddhist scholars began to systematize their own metaphysical and epistemological positions, sometimes in response to or dialogue with non-Buddhist systems like Vaià Âeá¹£ika.
Vaià Âeá¹£ika philosophy is considered one of the earliest proponents of atomism in Indian thought. According to this view, all material objects are composed of indivisible, eternal atoms (paramÃÂá¹Âu) of four elements: earth, water, fire, and air. These atoms combine through conjunction (saá¹Âyoga) and inherence (SamavÃÂya) to form complex, perceivable objects.
Buddhist schools, particularly the SarvÃÂstivÃÂda and later TheravÃÂda Abhidhamma and YogÃÂcÃÂra traditions, developed their own theories of atomism and constituent elements (dharmas). These Buddhist atoms, however, were fundamentally momentary and non-substantial, existing only in a single instant before giving rise to a successor. While structurally similar in positing basic building blocks of reality, Buddhist atomism served a different function: not to establish a permanent material substratum, but to support doctrines of impermanence (anitya) and dependent origination.
Some scholars suggest that the development of Buddhist atomism may have been in part a philosophical response to the atomistic realism of Vaià Âeá¹£ika, offering a counter-theory that maintained empirical rigor without conceding to metaphysical permanence.
Vaià Âeá¹£ika epistemology, though not as developed as NyÃÂya's, accepted perception (Pratyaká¹£a) and inference (anumÃÂna) as valid means of knowledge (PramÃÂá¹Âa). Over time, Vaià Âeá¹£ika and NyÃÂya merged into a unified system, often referred to as the NyÃÂya-Vaià Âeá¹£ika school, particularly from the post-Uddyotakara period (c. 5th century CE onward). This synthesis brought Vaià Âeá¹£ika metaphysics into the sphere of logical and epistemological debate.
Buddhist logicians, especially DignÃÂga and Dharmakërti, engaged deeply with NyÃÂya-Vaià Âeá¹£ika thinkers, critiquing their views on perception, inference, and universals. While these critiques were often aimed at NyÃÂya formulations, many of the underlying metaphysical positionsâÂÂsuch as the reality of substances or inherenceâÂÂwere drawn from Vaià Âeá¹£ika doctrines.
This interaction spurred Buddhist thinkers to clarify and refine their own positions on cognition, objecthood, and conceptual construction (vikalpa). For example, Dharmakërti's theory of Apoha (exclusion) as the basis of conceptual cognition can be read as a direct challenge to both Vaià Âeá¹£ika's realist universals (SÃÂmÃÂnya) and their role in perception.
There are also conceptual parallels that may reflect shared cultural and intellectual frameworks rather than direct influence. For instance, both Vaià Âeá¹£ika and Buddhist Abhidharma employ classificatory taxonomies to understand reality. Vaià Âeá¹£ika lists six or seven categories of being (PadÃÂrtha), including substance, quality, motion, generality, particularity, and inherence. Abhidharma texts similarly analyze reality into lists of mental and physical phenomena (dharmas), though from a phenomenological rather than ontological standpoint.
However, the purpose and metaphysical commitments of these taxonomies diverge significantly. Vaià Âeá¹£ika aims at a stable ontology of the external world, whereas Buddhist taxonomy serves soteriological aims by analyzing experience into impermanent, non-self constituents.
While Vaià Âeá¹£ika did not exert a dominant or sustained influence on Buddhist philosophy, its presence in the broader philosophical landscape of classical India prompted Buddhist responsesâÂÂespecially in areas of atomism, realism, and classification. These responses were often critical and reformulative, leading to uniquely Buddhist formulations of key metaphysical and epistemological concepts. Through its integration with NyÃÂya, Vaià Âeá¹£ika indirectly contributed to shaping Buddhist logic and theory of knowledge during the scholastic and classical periods of Indian philosophy.
Nagarjuna (c. 150 â c. 250 CE), one of the most influential Buddhist thinkers, defended the theory of the emptiness (shunyata) of phenomena and attacked theories that posited an essence or true existence (svabhava) to phenomena in his magnum opus The Fundamental Verses on the Middle Way. He used the Buddhist catuá¹£koá¹Âi ("four corners" or "four positions") to construct reductio ad absurdum arguments against numerous theories which posited essences to certain phenomena, such as causality and movement. In Nagarjuna's works and those of his followers, the four positions on a particular thesis are negated or ruled out () as exemplified by the first verse of Nagarjuna's Middle way verses which focuses on a critique of causation:
<blockquote>Entities of any kind are not ever found anywhere produced from themselves, from another, from both [themselves and another], and also from no cause.</blockquote>
Nagarjuna also famously relied upon refutation based argumentation (vitanda) drawing out the consequences (prasaá¹ ga) and presuppositions of his opponents' own theories and showing them to be self refuting. Because the vaitandika only seeks to disprove his opponents arguments without putting forward a thesis of his own, the Hindu Nyaya school philosophers such as Vatsyayana saw it as unfair and also irrational (because if you argue against P, you must have a thesis, mainly not-P). According to Matilal, Nagarjuna's position of not putting forth any implied thesis through his refutations would be rational if seen as a form of illocutionary act.
Nagarjuna's reductions and the structure of the catuá¹£koá¹Âi became very influential in the Buddhist Madhyamaka school of philosophy which sees itself as a continuation of Nagarjuna's thought. Nagarjuna also discusses the four modes of knowing of the Nyaya school, but he is unwilling to accept that such epistemic means bring us ultimate knowledge.
Nagarjuna's epistemic stance continues to be debated among modern scholars, his skepticism of the ability of reason and language to capture the nature of reality and his view of reality as being empty of true existence have led some to see him as a skeptic, mystic, nihilist or agnostic, while others interpret him as a Wittgensteinian analyst, an anti-realist, or deconstructionist.
Nagarjuna is also said to be the author of the UpÃÂyaà Âá¹Âdaya one of the first Buddhist texts on proper reasoning and argumentation. He also developed the Buddhist theory of two truths, defending ultimate truth as the truth of emptiness.
Vasubandhu was one of the first Buddhist thinkers to write various works on sound reasoning and debate, including the VÃÂdavidhi (Methods of Debate), and the VÃÂdavidhÃÂna (Rules of Debate).
Vasubandhu was influenced by the system of the Nyaya school. Vasubandhu introduced the concept of 'logical pervasion' (vyapti). He also introduced the trairà «pya (triple inferential sign).
The trairà «pya is a logical argument that contains three constituents which a logical âÂÂsignâ or âÂÂmarkâ (linga) must fulfill to be 'valid source of knowledge' (pramana):
DignÃÂga (c. 480 â 540 CE) is the founder of an eponymous tradition of Buddhist logic and epistemology which was widely influential in Indian philosophy due to the introduction of unique epistemological questions. According to B.K. Matilal, DignÃÂga "was perhaps the most creative logician in medieval (400-1100) India."
DignÃÂga's tradition of Buddhist logic is sometimes called the "School of DignÃÂga" or "The School of DinnÃÂga and Dharmakërti". In Tibetan, it is often called âÂÂthose who follow reasoningâ (Tibetan: rigs pa rjes su âÂÂbrang ba); in modern literature, it is sometimes known by the Sanskrit "pramÃÂá¹ÂavÃÂda", often translated as "the epistemological school" or "the logico-epistemological school."
DignÃÂga defended the validity of only two pramÃÂá¹Âas (instruments of knowledge), perception and inference, in his magnum opus, the PramÃÂá¹Âa-samuccaya.
His theory does not "make a radical distinction between epistemology and the psychological processes of cognition." As noted by Cristian Coseru, DignÃÂga's theory of knowledge is strongly grounded in perception "as an epistemic modality for establishing a cognitive event as knowledge".
Since perception is information that is acquired through the senses, it is not susceptible to error. However, there is susceptibility to error in processes of interpretation, including mental construction and inferential thinking.
DignÃÂga also wrote on language and meaning. His "apoha" (exclusion) theory of meaning was widely influential. For DignÃÂga, a word can express its own meaning only by repudiating other meanings. The word 'cow' gives its own meaning only by the exclusion of all those things which are other than cow.
Following DignÃÂga, Dharmakërti (c. 7th century), contributed significantly to the development and application of Buddhist pramana theory. Dharmakërti's PramÃÂá¹ÂavÃÂrttika, remains in Tibet as a central text on pramana and was widely commented on by various Indian and Tibetan scholars.
Dharmakërti's theory of epistemology differed from DignÃÂga's by introducing the idea that for something to be a valid cognition it must "confirm causal efficacy" (arthakriyÃÂsthiti) which "consists in [this cognitionâÂÂs] compliance with [the objectâÂÂs capacity to] perform a function" (PramÃÂá¹ÂavÃÂrttika 2.1ac).
He was also one of the primary theorists of Buddhist atomism, according to which the only items considered to exist or be ultimately real are momentary particulars (svalaká¹£aá¹Âa) including material atoms and momentary states of consciousness (dharmas). Everything else is considered to be only conventional (saá¹Âvá¹Âtisat) and thus he has been seen as a nominalist, like DignÃÂga.
Vincent Eltschinger has argued that Buddhist epistemology, especially Dharmakërti's, was an apologetic response to attacks by hostile Hindu opponents and thus was seen by Buddhists as "that which, by defeating the outsiders, removes the obstacles to the path towards liberation." Coseru meanwhile simply notes the inseparability of epistemic concerns from spiritual praxis for Buddhist epistemologists such as Dharmakërti:<blockquote>It is this praxis that leads a representative thinker such as Dharmakërti to claim that the Buddha, whose view he and his successors claim to propound, is a true embodiment of the sources of knowledge. Thus, far from seeing a tension between empirical scrutiny and the exercise of reason, the Buddhist epistemological enterprise positions itself not merely as a dialogical disputational method for avoiding unwarranted beliefs, but as a practice aimed at achieving concrete, pragmatic ends. As Dharmakërti reminds his fellow Buddhists, the successful accomplishment of any human goal is wholly dependent on having correct knowledge.</blockquote>
The Buddhist philosophers who are part of this pramÃÂá¹ÂavÃÂda tradition include numerous other figures who followed DignÃÂga and Dharmakërti. They developed their theories further, commented on their works and defended their theories against Hindu and Buddhist opponents.
Fyodor Stcherbatsky divided the followers and commentators on Dharmakirti into three main groups:
Some of the other figures of the epistemological school include:
DignÃÂga also influenced non-Buddhist Sanskrit thinkers. According to Lawrence J. McCrea, and Parimal G. Patil, DignÃÂga set in motion an "epistemic turn" in Indian philosophy:
The Hindu philosophers, especially those of the NyÃÂya, Vaiseshika and Vedanta schools, were in constant debate with the Buddhist epistemologists, developing arguments to defend their realist position against the nominalism of the Buddhists. NyÃÂya-Vaiseshika thinkers such as Uddyotakara and Prashastapada critiqued the views of Dignaga as they developed their own philosophy.
VÃÂcaspati Mià Âra's NyÃÂya-vÃÂrtika-tÃÂtparya-tikàis almost entirely focused on outlining and defeating the arguments of the Buddhist epistemologists. PrabhÃÂkara (active c. 6th century) meanwhile, may have been influenced by Buddhist reasoning to move away from some of the realistic views of older MëmÃÂá¹Âsàthought. The Vedanta scholar à Ârëhará¹£a who attacked the realism of NyÃÂya may have been influenced by the Buddhists as well. Even the "New Reason" (Navya NyÃÂya) scholar Gaá¹ geà Âa UpÃÂdhyÃÂya shows an influence from the Buddhist epistemological school, in his arrangement of his TattvacintÃÂmaá¹Âi.
BhÃÂvaviveka (c. 500 â c. 578) appears to be the first Buddhist logician to employ the "formal syllogism" (Wylie: sbyor ba'i tshig; Sanskrit: prayoga-vÃÂkya) in expounding the MÃÂdhyamaka view, which he employed to considerable effect in his commentary to Nagarjuna's Mà «lamadhyamakakÃÂrikàentitled the PrajñÃÂpradëpa. To develop his arguments for emptiness, BhÃÂvaviveka drew on the work of DignÃÂga which put forth a new way of presenting logical arguments.
BhÃÂvaviveka was later criticized by Chandrakirti (540âÂÂ600) for his use of these positive logical arguments. For Chandrakirti, a true MÃÂdhyamika only uses reductio ad absurdum arguments and does not put forth positive arguments. Chandrakirti saw in the logico-epistemic tradition a commitment to a foundationalist epistemology and essentialist ontology. For Chandrakirti, a MÃÂdhyamika's job should be to just deconstruct concepts which presuppose an essence.
In spite of Chandrakirti's critique, later Buddhist philosophers continued to explain Madhyamaka philosophy through the use of formal syllogisms as well as adopting the conceptual schemas of the Dignaga-Dharmakirti school along with those of the closely related Yogacara school). These figures include Jñanagarbha (700âÂÂ760), à ÂÃÂntaraká¹£ita (725âÂÂ788), Kamalaà Âëla, Haribhadra and RatnÃÂkaraà ÂÃÂnti (c.1000). Another thinker who worked on both pramana and Madhyamaka was the Kashmiri pandita Parahitabhadra.
This tendency within Madhyamaka is termed SvÃÂtantrika, while Chandrakirti's stance is termed Prasangika. The Svatantrika-Prasaá¹ gika distinction is a central topic of debate in Tibetan Buddhist philosophy. In Tibetan Buddhism, those who follow this method and also make use of YogÃÂcÃÂra doctrines are called YogÃÂcÃÂra-SvÃÂtantrika MÃÂdhyamika (Tibetan: Rnal âÂÂbyor spyod paâÂÂi dbu ma rang rgyud pa).
Probably the most influential figure in this tradition is à ÂÃÂntaraká¹£ita. According to James Blumenthal<blockquote>à ÂÃÂntaraká¹£ita attempted to integrate the anti-essentialism of NÃÂgÃÂrjuna with the logico-epistemological thought of DignÃÂga (ca. 6th c.) and Dharmakërti (ca. 7th c.) along with facets of YogÃÂcÃÂra/CittamÃÂtra thought into one internally consistent, yet fundamentally Madhyamaka system.</blockquote>This synthesis is one of the last major developments in Indian Buddhist thought, and has been influential on Tibetan Buddhist philosophy.
Tom Tillemans, in discussing the Tibetan translation and assimilation of the logico-epistemological tradition, identifies two currents and transmission streams:
The first is the tradition of the Kadampa scholar Ngok Lodzawa Loden Shayrap (1059âÂÂ1109) and Chapa Chögyi Sengge (1109âÂÂ69) and their disciples, mainly located at Sangpu Neutok. Chapa's Tshad maâÂÂi bsdus pa (English: "Summaries of Epistemology and Logic") became the groundwork for the "Collected Topics" (Tibetan: ; Wylie: bsdus grwa) literature, which in large part furnished the Gelugpa-based logical architecture and epistemology. These two scholars (whose works are now lost) strengthened the influence of Dharmakirti in Tibetan Buddhist scholarship.
There is also another tradition of interpretation founded by Sakya Pandita (1182âÂÂ1251), who wrote the Tshad-ma rigs-gter (English: "Treasury of Logic on Valid Cognition"). Sakya pandita secured the place of Dharmakirti's Pramanavarttika as the foundational text on epistemology in Tibet. Later thinkers of the Gelug school such as Gyeltsap and Kaydrup attempted a synthesis of the two traditions, with varying results. This is because the views of Chapa were mostly that of Philosophical realism, while Sakya pandita was an anti-realist.