Nyaya (Sanskrit meaning "rational argument") is one of the six orthodox (astika) schools of Hindu philosophy that focuses on logic. Based on texts known as the Nyaya Sutras, written by Aksapada Gautama (ca. sixth century B.C.E.), this school made a very significant contribution to the study of logic and epistemology in Indian thought. In particular, it was renowned for its rigor of philosophical discourse, and the majority of the other Indian schools adopted its logical methodology, whether orthodox or heterodox.


Nyaya's most important contribution to Hindu thought is its elucidation of the pramanas (tools of epistemology). Its followers believe that obtaining valid knowledge is the only way to obtain release from suffering. They therefore took great pains to identify valid sources of knowledge and to distinguish these from mere false opinions. They argued that there are exactly four sources of knowledge: perception, inference, comparison and testimony. However, knowledge obtained through each of these sources can still be either valid or invalid. As a result, Nyaya scholars again went to great pains to identify, in each case, what it took to make knowledge valid—in the process creating a number of explanatory schemes. In this sense, Nyaya is probably the closest Indian equivalent to contemporary analytic philosophy.


The beginning of Nyaya can be traced back to the writings of Aksapada Gautama (ca. sixth century B.C.E.) who wrote the Nyaya Sutras. Gautama founded the Nyaya school, which was closely affiliated to the Vaisheshika (atomism) school of Hindu philosophy. While Nyaya centered around logic and epistemology, Vaisesika was primarily a metaphysical system of thought that classifies all beings into seven categories, and postulated that all objects in the physical universe are reducible to a finite number of atoms. The exact periods of the origin of Vaisesika have not been established; it is thought to be more ancient than Nyāya, and may have preceded, but was at least contemporary with, Buddhism and Jainism. The founder of Vaisesika is considered to be Kanāda, author of the Vaishesika Sutra, written sometime after 300 B.C.E..


The Naiyanikas (the Nyaya scholars) accepted four means of obtaining knowledge (pramana)—Perception, Inference, Comparison, and Verbal Testimony or Word. Each of these instruments of knowledge is elucidated below:

1) Perception, called PratyakŞha, occupies the foremost position in the Nyaya epistemology. Perception is defined by sense-object contact and can be of two types:

A) Ordinary (Laukika or Sadharana) perception involving the six senses—sight, smell, hearing, touch, taste—and awareness of these by the mind.
B) Extra-ordinary (Alaukika or Asadharana) perception that involves Samanyalakshana (perceiving generality from a particular object), Jñanalakshana (when one sense organ can also perceive qualities not attributable to it, such as when seeing a chili, one knows that it would be bitter or hot), and Yogaja (when certain human beings, from the power of Yoga, can perceive past, present and future and may have supernatural abilities).

2) Inference, called Anumana, is also accepted by Nyaya as a valid means of knowledge. 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:

  • There is fire on the hill (called Pratijñā, required to be proved).
  • Because there is smoke there (called Hetu, reason).
  • Wherever there is fire, there is smoke (called Udaharana, i.e., the “example”).
  • There is smoke on the hill (called Upanaya, reaffirmation).
  • Therefore there is fire on the hill (called Nigamana, conclusion).

In Nyaya terminology for this example, the hill would be called as paksha (minor term), the fire is called as sadhya (major term), the smoke is called as hetu, and the relationship between the smoke and the fire is called as vyapti (middle term). Hetu further has five characteristics:

  • It must be present in the Paksha.
  • It must be present in all positive instances.
  • It must be absent in all negative instances.
  • It must not incompatible with the minor term or Paksha.
  • All other contradictions by other means of knowledge should be absent.

The Nyaya school classified inference into several types: inference for oneself (Svarthanumana), inference for others (Parathanumana), 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 Nyaya theory of error is similar to that of Kumarila's Viparita-khyati (see Mimamsa). The Nyayayikas also believe that error is due to a wrong synthesis of the presented and the represented objects. The represented object is confused with the presented one. The word 'anyatha' means 'elsewise' and 'elsewhere' and both these meanings are brought out in error. The presented object is perceived elsewise and the represented object exists elsewhere. They further maintain that knowledge is not intrinsically valid but becomes so on account of extraneous conditions (paratah pramana during both validity and invalidity).

3) Comparison, called Upamana, is the knowledge of the relationship between a word and the object denoted by the word. It is produced by the knowledge of resemblance or similarity, given some pre-description of the new object beforehand.

4) Word, or Shabda is also accepted as a pramana. It can be of two types, Vaidika (Vedic), which are the words of the four sacred Vedas, and are described as truth, and Laukika, or words and writings of trustworthy human beings.


Early Naiyanikas wrote very little about God (Ishvara). However, the ascendancy of Buddhist doctrine in India provoked the Hindu Naiyanikas to enter into philosophical disputes with Buddhists. The Naiyanikas tried to prove the existence of God through logic, and they gave the following nine proofs for the existence of God, which are enumerated in Udayana's Nyaya Kusumanjali:

  • Kāryāt (lit. "from effect"): An effect is produced by a cause, and similarly, the universe must also have a cause. Causes (according to Naiyanikas) are of three kinds: Samavayi (in case of the universe, the atoms), Asamavayi (the association of atoms) and Nimitta (which is Ishvara). The active cause of the world must have an absolute knowledge of all the material of creation, and hence it must be God. Hence from the creation, the existence of the Creator is allegedly proved.
  • Āyojanāt (lit., "from combination"): Atoms are inactive and properties are unphysical. Thus it must be God who creates the world with his will by causing the atoms to join. Self-combination of inanimate and lifeless things is not possible, otherwise atoms would only combine at random, creating chaos. Thus there must be the hand of a wise organizer behind the systematic grouping of the ultimate atoms into dyads and molecules. That final organizer is God.
  • Dhŗité (lit., "from support"): Just as a material thing falls off without a support, similarly, God is the supporter and bearer of this world, without which the world would not have remained integrated. This universe is hence superintended within God, which proves his existence.
  • Padāt (lit., "from word"): Every word has the capability to represent a certain object. It is the will of God that a thing should be represented by a certain word. Similarly, no knowledge can come to us of the different things here, unless there is a source of this knowledge. The origin of all knowledge should be omniscient, and, consequently, omnipotent. Such a being is not to be seen in this universe, and so it must be outside it. This being is God.
  • Pratyatah (lit, "from faith"): the Hindu holy scriptures, the Vedas, are regarded as the source of eternal knowledge. Their knowledge is free from fallacies and is widely believed as a source of proof. Their authors cannot be human beings because human knowledge is limited. They cannot obtain knowledge of past, present and future and in-depth knowledge of mind. Hence only God can be the creator of the Vedas. Hence his existence is proved from his being the author of the Vedas, which he revealed to various sages over a period of time.
  • Shrutéh (lit., "from scriptures"): The Shrutis extol God and talk about his existence. "He is the lord of all subjects, omniscient and knower of one's internal feelings; He is the creator, cause and destroyer of the world," say the Shrutis. The Shrutis are regarded as a source of proofs by Naiyanikas. Hence the existence of God is proved.
  • Vākyāt (lit., "from precepts"): Again, the Veda must have been produced by a person because it has the nature of "sentences," in other words, the sentences of the Veda were produced by a person because they have the nature of sentences, just as the sentences of beings like ourselves. That person must have been God.
  • Samkhyāvişheshāt (lit., "from the specialty of numbers"): The size of a dyad or a molecule depends on the number of the atoms that go to constitute it. This requisite number of the atoms that go to form a particular compound could not have been originally the object of the perception of any human being; so its contemplator must be God.
  • Adŗişhţāt (lit., "from the unforeseen"): It is seen that some people in this world are happy, some are in misery. Some are rich and some poor. The Naiyanikas explain this by the concept of Karma and reincarnation. The fruit of an individual's actions does not always lie within the reach of the individual who is the agent. There ought to be, therefore, a dispenser of the fruits of actions, and this supreme dispenser is God.

Nyaya arguments for monotheism

Not only have the Naiyanikas given proofs for the existence of God, but they have also given an argument that such a God can only be one. In the Nyaya Kusumanjali, this is discussed against the proposition of the Mimamsa school that there were many demigods (Devas) and sages (rishis) in the beginning, who wrote the Vedas and created the world. Nyaya says that:

[if they assume such] omniscient beings, those endowed with the various superhuman faculties of assuming infinitesimal size, etc., and capable of creating everything, then we reply that the law of parsimony bids us assume only one such, namely Him, the adorable Lord. There can be no confidence in a non-eternal and non omniscient being, and hence it follows that according to the system which rejects God, the tradition of the Veda is simultaneously overthrown; there is no other way open.

In other words, Nyaya says that the polytheist would have to give elaborate proofs for the existence and origin of his several celestial spirits, none of which would be logical. So it is much more logical to assume only One, eternal and omniscient God.


Nyaya's most important contribution to Hindu thought is its elucidation of the pramanas (tools of epistemology). It developed a system of logic that, subsequently, was adopted by the majority of the other Indian schools, orthodox or not. Nyaya differs from Aristotelian logic in that it is more than logic in its own right. Its followers believed that obtaining valid knowledge was the only way to obtain release from suffering. They therefore took great pains to identify valid sources of knowledge and to distinguish these from mere false opinions.


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External links

All links retrieved February 2, 2015.

General Philosophy Sources


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