The Nyāya Sūtras is an ancient Indian Sanskrit
text composed by Akṣapāda Gautama, and
the foundational text of the Nyaya school
of Hindu philosophy.
The date when the text was composed, and the
biography of its author is unknown, but variously
estimated between 6th-century BCE and 2nd-century
CE.
The text may have been composed by more than
one author, over a period of time.
The text consists of five books, with two
chapters in each book, with a cumulative total
of 528 aphoristic sutras, about rules of reason,
logic, epistemology and metaphysics.The Nyāya
Sūtras is a Hindu text, notable for focusing
on knowledge and logic, and making no mention
of Vedic rituals.
The first book is structured as a general
introduction and table of contents of sixteen
categories of knowledge.
Book two is about pramana (epistemology),
book three is about prameya or the objects
of knowledge, and the text discusses the nature
of knowledge in remaining books.
It set the foundation for Nyaya tradition
of the empirical theory of validity and truth,
opposing uncritical appeals to intuition or
scriptural authority.The Nyaya sutras cover
a wide range of topics, including Tarka-Vidyā,
the science of debate or Vāda-Vidyā, the
science of discussion.
The Nyāya Sutras are related to but extend
the Vaiśeṣika epistemological and metaphysical
system.
Later commentaries expanded, expounded and
discussed Nyaya sutras, the earlier surviving
commentaries being by Vātsyāyana (c.450–500
CE), followed by the Nyāyavārttika of Uddyotakāra
(c. 6th–7th centuries), Vācaspati Miśra's
Tātparyatīkā (9th century), Udayana's Tātparyapariśuddhi
(10th century), and Jayanta's Nyāyamañjarī
(10th century).
== Author and chronology ==
The Nyaya-sutras is attributed to Gautama,
who was at least the principal author.
According to Karl Potter, this name has been
a very common Indian name, and the author
is also reverentially referred to as Gotama,
Dirghatapas and Aksapada Gautama.
Little is known about Gautama, or which century
he lived in.
Scholarly estimates, based on textual analysis,
vary from the 6th century BCE, making him
a contemporary of Buddha and Mahavira, to
as late as the 2nd century CE.
Some scholars favor the theory that the cryptic
text Nyaya-sutras was expanded over time by
multiple authors, with the earliest layer
from about mid-first millennium BCE that was
composed by Gautama.
The earliest layer is likely to be Book 1
and 5 of the text, while Book 3 and 4 may
have been added last, but this is not certain.
One may sum up the situation pretty safely
by saying that we have not the vaguest idea
who wrote the Nyayasutras or when he lived.
It is likely, states Jeaneane Fowler, that
Nyaya and the science of reason stretch back
into the Vedic era; it developed in the ancient
Indian tradition that involved "dialectical
tournaments, in the halls of kings and schools
of Vedic philosophers", and Gautama was the
one who distilled and systematized this pre-existing
knowledge into sutras, or aphoristic compilations
called nyayasutras.The Nyaya school of Hinduism
influenced all other schools of Hindu philosophy,
as well as Buddhism.
Despite their differences, these scholars
studied with each other and debated ideas,
with Tibetan records suggesting that Buddhist
scholars spent years residing with Hindu Nyaya
scholars to master the art of reasoning and
logic.
This cooperation has enabled scholars to place
the currently surviving version of the Nyayasutras,
to a terminus ante quem (completed before)
date of about the 2nd century CE, because
one of the most famous and established Buddhist
scholars of that era, Nagarjuna, explicitly
states, "sutra 4.2.25 is addressed against
the Madhyamika system" of Buddhism.
Other ancient Buddhist texts confirm that
Nyayasutras existed before them, and the text
is considered the primary text of old Nyaya
school of Hinduism.
== Structure ==
The text is written in sutra genre.
A sutra is a Sanskrit word that means "string,
thread", and represents a condensed manual
of knowledge of a specific field or school.
Each sutra is any short rule, like a theorem
distilled into few words or syllables, around
which "teachings of ritual, philosophy, grammar
or any field of knowledge" can be woven.
Sutras were compiled to be remembered, used
as reference and to help teach and transmit
ideas from one generation to the next.The
Nyayasutra is divided into five books, each
book subdivided into two chapters each.
The structure of the text is, states Potter,
a layout of ahnikas or lessons served into
daily portions, with portion consisting of
a number of sutras or aphorisms.
The architecture of the text is also split
and collated into prakaranas or topics, which
later commentators such as Vatsyayana and
Vacaspati Misra utilized to compose their
bhasya, ancient texts that have survived into
the modern era.
There are several surviving manuscripts of
the Nyayasutras, with a slight difference
in number of sutras, of which the Chowkhamba
edition is often studied.
== Content ==
The first sutra 1.1.1 of the text asserts
its scope and the following sixteen categories
of knowledge as a means to gain competence
in any field of interest:
Perfection is attained by the correct knowledge
about true nature of sixteen categories: means
of right knowledge (pramāṇa); object of
right knowledge (prameya); doubt (samsaya);
purpose (prayojana); familiar instance (dṛṣṭānta);
established tenet (siddhānta); members of
an inference (avayava); reasoning (tarka);
ascertainment or results (nirṇaya); discussion
(vāda); sophistic disputations (jalpa); cavil
(vitaṇḍa); fallacies (hetvābhāsa); quibbles
(chala); futile rejoinders (jāti); and methods
of losing an argument (nigrahasthāna).
These sixteen categories cover many sections
of the text.
The verse 1.1.2 of the Nyāya Sūtra declares
the text's goal is to study and describe the
attainment of liberation of soul from wrong
knowledge, faults and sorrow, through the
application of above sixteen categories of
perfecting knowledge.
=== Means of attaining valid knowledge ===
The Nyaya-sutras assert the premise that "all
knowledge is not intrinsically valid", that
"most knowledge is not valid unless proven"
and "truth exists whether we human beings
know it or not".
However, states Fowler, the text accepts the
foundation that "some knowledge is self evident"
and axiomatic in every field of knowledge,
which can neither be proven nor needs proof,
such as "I am conscious", "I think" and "soul
exists".
Furthermore, the text presents its thesis
that knowledge is not self-revealing, man
must make effort to gain knowledge and this
is a systematic process that empowers one
to learn correct knowledge, and abandon incorrect
knowledge.The Nyāya sutras asserts and then
discusses four reliable means of obtaining
knowledge (pramāṇa), viz., Perception,
Inference, Comparison and Reliable Testimony.
==== Pratyaksha: Perception ====
The Nyayasutras assert that perception is
the primary proper means of gaining true knowledge.
All other epistemic methods are directly or
indirectly based on perception, according
to the text, and anything that is claimed
to be "true knowledge" must be confirmed or
confirmable by perception.
This it terms as the doctrine of convergence,
and this doctrine includes direct or implied
perception.
Gautama defines perception as the knowledge
that arises by the contact of one or more
senses with an object or phenomenon.
Gautama dedicates many sutras to discuss both
the object and subject in the process of perception,
and when senses may be unreliable.
Erratic eyesight or other senses (Avyabhicara)
can be a source of doubt or false knowledge,
as can prejudgmental or prejudicial state
of mind, states the Nyayasutras.The text asserts
Pratyaksa leads to Laukika or ordinary knowledge,
where the five senses directly and clearly
apprehend a reality, and this is true definite
knowledge according to the text.
It defines indefinite knowledge as one where
there is doubt, and the text gives an example
of seeing a distant stationary object in the
evening and wondering whether it is a post
or a man standing in the distance.
In some of these cases, states Nyayasutras,
correct knowledge is formulated by the principle
of cumulative evidence.
Manas (mind) is considered an internal sense,
in the text, and it can either lead to correct
or incorrect knowledge depending on how it
includes, excludes or integrates information.
These ideas are compiled, in later chapters
of the text, into its treatise on Aprama (Theory
on Errors).
==== Anumana: Inference ====
The epistemic rationale for inference as a
reliable source of knowledge, and Nyaya's
theory has been a major contribution to the
diverse schools of Hinduism, and other schools
looked up to Nyaya scholars for insights on
correct knowledge and incorrect knowledge
through inference.
The sections in Nyayasutras on inference blossomed
into a treatise on syllogism over time.Nyayasutras
defines inference as the knowledge that follows
or derives from other knowledge.
It always follows perception, states the text,
and is a universal relation or essential principle.
One form of inference is a Purvavat, or as
Fowler translates, "from cause to effect or
a priori".
Thus, if a path or road is wet or river is
swollen, states the text, then "it has rained"
is a valid knowledge.
The sutras assert that the "universal relationship"
between the two is necessary for correct,
reliable knowledge, that is "if in all cases
of A, B is true, then one may correctly infer
B whenever A is perceived".
Further, there is a causal relation between
the two, whether one knows or not of that
cause, but inferred knowledge does not require
one to know the cause for it to be valid knowledge,
states Nyayasutra.
The text states one must not confuse coexistence
as a universal relation, and that while deduction
and induction both are useful and valid means
for gaining true knowledge, it lists rules
when this method can lead to false knowledge.
==== Upamana: Comparison and analogy ====
The word upamana, states Fowler, is a compound
of upa (similarity) and mana (knowledge).
It is a means of gaining knowledge based on
"similarity, comparison, analogy", and considered
reliable in Nyaya and many schools of Hinduism
(but not in Vaisheshika and Charvaka, or Buddhism).The
Nyayasutras define upamana as the knowledge
of a thing based on "its likeness to another
thing which is familiar".
It differs from Anumana (inference) in lacking
a direct or immediate causal relation.
It differs from Pratyaksha (perception), states
the text, in using a linguistic referent and
the foundation of pre-existing knowledge within
the individual and what he learnt from his
teachers, friends, family and past knowledge
inherited from the wise, through a process
of social cooperation.
The Upamana method is secondary, it relies
on perception, combined with linguistic referent
and context.
Comparison is not isolated pramana means,
and sometimes works together with the Anumana
and Sabda epistemic methods.
Comparison is, in Nyayasutras, the process
of permeating or infusing hypothesis, examples
and tests, thus leading to objectivity and
correct knowledge about something new and
what one already presumes to know.
==== Shabda: Testimony and reliable sources
====
Śabda (Sanskrit: शब्द, Word), in
Nyayasutras, means relying on word, testimony
of a reliable source.
Sabda-pramana has been an accepted and reliable
method to knowledge by all orthodox schools
of Hinduism including Nyaya, asserting 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 parents, 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 correct knowledge is
either spoken or written, but it is through
Sabda (words).
In addition to words, state the Nyayasutras,
Shabda as a means of true knowledge depends
on an agreed convention on what words mean,
the structure of sentences, establishing context
and their import.
The source must be reliable and comprehensible,
and the receiver of knowledge must be able
to understand the knowledge therefrom.The
reliability of the source is important, and
legitimate knowledge can only come from the
Sabda of reliable sources.
The schools of Hindu philosophy have debated
if, how and when reliability of source can
be objectively established.
Gautama, in the Nyayasutras, offers a description
for a reliable source.
Some schools, such as Charvaka, state that
this is never possible, and therefore Sabda
in the Vedas or anyone else, can never be
a proper pramana.
Other schools debate means to establish reliability.
=== Theory of proper Argument ===
The text, in sutras 1.1.32 and 1.1.39 presents
its theory of proper Argument, stating that
it must include five members:
Pratijna – the proposition or hypothesis
(that which needs to be proved or decided)
Hetu – the reason (can be positive or negative)
Udaharana – the example(s) (that which is
independently confirmed or confirmable)
Upanaya – the application (validity test,
or example to the instance)
Nigamana – the conclusion (either hypothesis
is true or false or in doubt)The text defines
and aphoristically discusses each of these.
=== Theory of doubt as incomplete knowledge
===
The Nyayasutras define and discuss Samsaya
(Sanskrit: संशय, doubt) in sutras
1.1.23, 2.1.1 to 2.1.7, 3.2.1, 4.2.4 among
others.
This discussion is similar to those found
in other schools of Hindu philosophy, expands
on the theory of doubt presented by Kanada
in the Vaisheshika school, but disagrees with
the Charvaka school's theory of doubt and
consequent "there is no empirical knowledge
ever".The theory of doubt, according to the
Nyayasutras, starts with the premise that
doubt is part of the human learning process
and occurs when conflicting possibilities
exist with regard to a cognized object.
Doubt is neither error nor absence of knowledge,
but a form of uncertainty and human struggle
with probability when it faces incomplete
or inconsistent information.
It is a knowledge that is possibly partially
valid and partially invalid, but doubt is
a form of knowledge that has positive value.
Doubt is an invitation to "proceed to further
investigation", asserts the text.
All four means of knowledge discovery (perception,
inference, comparison and testimony) may be
useful in this investigation, but doubt is
both a psychological state and a means to
knowledge, not in itself a valid knowledge,
according to the sutras.
=== Hetvabhasa, theory of errors ===
The Nyayasutra defines error as knowledge,
an opinion or a conclusion about something
that is different from what it really is.
Gautama states in the text that the error
is always in the process of cognition itself,
or the "subjective self", and not in the object.
It is the duty of the knowledge-seeker to
"test the validity of his knowledge", both
in assumptions or through practice (experience),
but neither the object of knowledge nor the
knowledge itself is responsible for errors;
only the knowledge-seeker and his process
of cognition is.
The Nyaya theory shares ideas on the theory
of errors with Advaita Vedanta, Buddhism and
Mimamsa schools of Indian philosophies, states
Rao, and these schools likely influenced each
other.The text identifies and cautions against
five kinds of fallacious reasoning (hetvabhasa)
in sutra 1.2.4, discussing each in the sutras
that follow, stating that these lead to false
knowledge, in contrast to proper reasoning
(hetu), which leads to true knowledge.
The five fallacies or errors, according to
Nyayasutras, are to be avoided, in addition
to watching for debating tricks (chala) used
by those whose aim isn't true knowledge.
The five forms of bogus reasoning identified
by the text, states Ganeri, are:
the wandering or erratic (Nyayasutra 1.2.5)
the contradictory (Nyayasutra 1.2.6)
the unproven (Nyayasutra 1.2.8)
the counterbalanced (Nyayasutra 1.2.7)
the untimely (overgeneralization across time,
or sublated, Nyayasutra 1.2.9)
=== Theory of causality ===
The Nyayasutras dedicate many sections on
causality and causal relations (Karana, Sanskrit:
कारण), particularly Book 4.
Causes, in Nyaya view states Fowler, are "antecedents
of their effects invariably and unconditionally".
A specific effect is produced by a specific
cause (plurality in causes accepted), and
in Nyayasutras view a specific cause produces
a specific effect and no other (plurality
in effect, or contradictory effect is not
accepted).
The sutras assert that there cannot be reciprocity
to a cause, either we misunderstand the cause
or misapprehend the effect.
The text rejects remote or supernatural causes,
and rejects that qualities are causes.
The text asserts that causes are immediately
antecedent, causes exist before an effect
in time, and to know something is to understand
the effect and the specific cause(s).The text
identifies three types of causes – inherent
or material cause (Samavayi-karana), non-inherent
cause (Asamavayi-karana), and efficient cause
(Nimitta-karana).
These, it states, arise from Dravya (substance),
Guna (quality) and Karma (action).
=== Theory of negatives ===
The text seeds the theory of negative entities,
where both being and non-being, presence and
absence of something is considered correct
and useful knowledge.
Absence of book on a table or absence of particular
color in a painting has a place in its epistemic
process, in addition to positively verifiable
characteristics of the table or a painting.
=== Atheism in Nyayasutras ===
Early Nyaya school scholars considered the
hypothesis of Ishvara as a creator God with
the power to grant blessings, boons and fruits.
However, the Nyayasutras and early Nyaya scholars
rejected this hypothesis, and were non-theistic
or atheists.In Nyayasutra's Book 4, Chapter
1 examines what causes production and destruction
of entities (life, matter) in universe.
It considers many hypotheses, including Ishvara.
Verses 19–21, postulates Ishvara exists
and is the cause, states a consequence of
postulate, then presents contrary evidence,
and from contradiction concludes that the
postulate must be invalid.
Later scholars of Nyaya school reconsidered
this question and offered counter arguments
for what is God (Ishvara) and various arguments
to prove the existence of Ishvara.
The 5th century CE Nyaya school scholar Prastapada,
for example, revisited the premise of God.
He was followed by Udayana, who in his text
Nyayakusumanjali, interpreted "it" in verse
4.1.21 of Nyaya Sutra above, as "human action"
and "him" as "Ishvara", then he developed
counter arguments to prove the existence of
Ishvara, a reasoning that fueled the debate
and disagreements on God in Neo-Nyaya and
other Hindu traditions of 2nd millennium CE.
=== Soul, self exists, inner freedom ===
A large part of the third book of the Nyayasutras
is dedicated to the premise and the nature
of a Self (soul, atman) and its relation to
knowledge, liberation from sorrow and inner
freedom (moksha).
=== Philosophy: a form of Yoga ===
The sutras 4.2.42 to 4.2.48 of Nyayasutras,
states Stephen Phillips, state that "philosophy
is a form of yoga".The text recommends yogic
meditation in quiet places such as a forest,
cave or sandy beach in sutra 4.2.42, that
the knowledge seeker should purify one's soul
by Yamas, Niyamas and spiritualism of yoga
in sutra 4.2.46.
Meditation is a treasured and recommended
practice in the text, and extensively discussed
by Nyaya scholars that followed Aksyapada
Gautama.
Vatsyayana wrote in his commentary on Nyayasutras,
for example, that meditation is that which
enables the mind to contact one's soul, which
is accompanied by a conscious eagerness to
get at the truth, and such meditation is an
essential practice to gain true knowledge.The
Nyayasutras state that one must study the
means of correct knowledge and hold discussions
with the learned, sincere and unenvious fellow
seekers of knowledge state sutras 4.2.47 and
4.2.48.
One must, translates Phillips, take into account
"consideration of personal character as well
as the nature of beliefs held by the opponent",
in deciding the nature of one's discussions,
according to Nyayasutras.
In some cases, asserts the text, it is better
to avoid arguing with hostile opponents and
use methods of knowledge like "a fence is
used to safeguard the growth of seeds".
== Commentaries ==
The earliest surviving complete bhasya (review
and commentary) on Nyaya Sutras is by Vatsyayana.
This commentary itself inspired many secondary
and tertiary bhasya.
Vatsyayana's commentary has been variously
dated to be from the 5th century CE, or much
earlier around 2nd century BCE.
Another often studied surviving commentary
on the text is credited to Vacaspati Mishra
from about 9th century CE.
Other historical Indian commentaries and works
inspired by Nyayasutras and which have survived
into the modern era, include Nyaya-varttika
by 6th-century Uddyotakara, Nyaya-bhasyatika
by 6th-century Bhavivikta, another Nyaya-bhasyatika
by 7th-century Aviddhakarna, Nyaya-bhusana
by 9th-century Bhasarvajana, Nyaya-manjari
by 9th-century Kashmir scholar Jayanta Bhatta,
Nyaya-prakirnaka by 10th-century Karnata scholar
Trilocana, and Nyaya-kandali by 10th-century
Bengal scholar Sridhara.Numerous other commentaries
are referenced in other Indian historical
texts, but these manuscripts are either lost
or yet to be found.
Starting around 11th- to 12th century CE,
Udayana wrote a primary work, that built upon
and expanded the theories on reason found
in Nyayasutras.
Udayana's work created the foundation for
Navya-Nyaya (new Nyaya) school.
The Hindu scholar Gangesa of 13th- or 14th-century,
integrated the Gautama's Nyayasutras and Udayana's
Navya-Nyaya work, to create the influential
Tattvacintāmaṇi text considered a masterpiece
by scholars.
== Influence ==
=== On Hinduism's soul, Buddhism's no-soul
debate ===
The Nyaya-sutras have been one of the foundations
for the historic debate between Hinduism's
premise that ultimate reality and atman (soul)
exists, and Buddhism's premise that there
is voidness and anatta (no-soul).
In Nyaya-sutra, the Buddhist premises and
arguments to refute those premise are found
in many chapters, such as sutras of chapters
3.2, 4.1 and 4.2.
The text has been influential in this debate,
with the 2nd-century Buddhist scholar Nagarjuna
states that the Nyaya school and Buddhism
differ on their conception of Self (Atman)
and their views on the Vedas, and the sutra
4.2.25 of Nyayasutra is addressed against
the Madhyamika system of Buddhism.Nagarjuna's
Madhyamika-karika targets Nyaya-sutra, among
other Hindu texts, for his critique and in
order to establish his doctrine of no self
and voidness.
In this text, and Vigrahavya-vartani, he presents
his proof of voidness by challenging the Pramanas
at the foundation of Nyaya-sutras.
In his work Pramana-vihetana, Nagarjuna, takes
up each of the sixteen categories of knowledge
in Gautama's Nyaya-sutras at the foundation
of Nyaya's discussion of "soul exists and
the nature of soul in liberation process",
and critiques them using the argument that
these categories are relational and therefore
unreal.
The Nagarjuna's texts, along with Gautama's
Nyaya-sutras states Sanjit Sadhukhan, influenced
Vatsyayana's work who called Nagarjuna's doctrine
of voidness as flawed, and presented his arguments
refuting Nagarjuna's theory on "objects of
knowledge are unreal, like a dream or a form
of jugglery and a mirage", but by first presenting
his demonstration that the theory of reason
and knowledge in the Nyaya-sutras are valid.The
Buddhist thesis that all things are negative
in nature (inasmuch as a thing's nature is
constituted by its differences from others)
is rejected, as is the view that all things
are eternal or that all things are noneternal.
Both these latter views are untrue to experience.
=== On Vedanta traditions ===
The Nyayasutras were influential to the Vedanta
schools of Hindu philosophy, and provided
the epistemological foundations.
The terms Nyaya and Mimamsa were synonymous,
states Hajime Nakamura, in the earliest Dharmasutras
of 1st millennium BCE.
Over time, Nyaya, Mimamsa and Vedanta became
three distinct and related schools.
== See also ==
Debates in ancient India
== Notes ==
== References ==
=== 
Translations ===
Nandalal Sinha, Mahamahopadhyaya Satisa Chandra
Vidyabhusana, The Nyaya Sutras of Gotama,
The sacred books of the Hindus, 1930; Motilal
Banarsidass, 1990 reprint, ISBN 978-81-208-0748-8;
Munshiram Manoharlal reprint, 2003, ISBN 978-81-215-1096-7.
Ganganatha Jha, Nyaya- Sutras of Gautama (4
vols.), Motilal Banarsidass, 1999 reprint,
ISBN 978-81-208-1264-2.
== Further reading ==
J Ganeri (2001), Indian Logic: A Reader, Routledge,
ISBN 978-0700713066
Sue Hamilton, Indian Philosophy: A Very Short
Introduction (Oxford University Press, 2001)
ISBN 0-19-285374-0
B.K.
Matilal, Epistemology, Logic, and 
Grammar in Indian Philosophical Analysis (Oxford
University Press, 2005) ISBN 0-19-566658-5
J.N.
Mohanty, Classical Indian Philosophy (Rowman
& Littlefield, 2000) ISBN 0-8476-8933-6
== External links ==
The Nyâya Sutras of Gotama, SC Vidyabhushana
(1913), English Translation
Gautama's Nyayasutra without any commentary,
GRETIL version of Sanskrit text, University
of Goettingen, Germany
Nyāyasūtra: Devanagari, A SARIT Initiative,
German Research Foundation
Gautama's Nyayasutra with Vacaspatimisra's
commentary Nyayavarttikatatparyatika, GRETIL
version of Sanskrit text, University of Goettingen,
Germany
Gautama: Nyayasutra with Vatsyayana's commentary
Nyayabhasya, GRETIL version of Sanskrit text,
University of Goettingen, Germany
