1. Learning Objectives
2. Introduction
3. Concept of knowledge in Nyâya
4. Concept of perception in Nyâya: Nature and definition of perception
5. Kinds of perception

1. Ordinary and Extra-ordinary perception (Laukika and Alaukika Pratyaka)s
2. Indeterminate and Determinate perception (Nirvikalpa and Savikalpa pratyaka.
7. Let us sum up
8. Further Readings
9. Answers To Check Your Progress
10. Possible Questions


After going through this unit, you will be able to:
Describe the nature and definition of knowledge according to the Nyâya System.
Explain the concept of perception (pratyaka) of the Nyâya System.
Elaborate different kinds of perception found in the Nyâya System.


This unit introduces to you the ‘ Nyâya System’ of Indian philosophy. Nyâya is an orthodox system which was founded by the sage Gautama or Aksapada. The word ‘Nyâya’ means ‘argumentation.’ Nyâya System is also known as Tarkasâstra or the science of reasoning, Pramânasâstra or the science logic and epistemology, Hetuvidyâ or the science of causes, vadavidya or the science of debate, and anviksiki or the science of critical study. Gautama wrote the book ‘ Nyâya Sûtra’. This book was commented upon by Vâtsyâyana in his ‘Nyâya Bhâsya’. The other works of the Nyâya system are: Uddyotakara’s ‘Nyâya-Varttika’, Vâcaspati’s ‘Nyâya-Varttika-Tatparya-tika’, Udayana’s ‘ Nyâya- Kusumanjali’, Jayanta’s ‘Nyâyamanjari’ etc. The modern school of Indian logic begins with the famous work ‘Tattva-Cintamani’ of Gangesa. Some of the eminent Navya-Nyâya logicians are: Vasûdeva, Raghunatha, Mathuranâtha, Jagadisa and Gadâdhara.

Nyâya and Vaiúeika both are regarded to be ‘samânatantra’ or similar philosophy, because these two systems agree in certain respects. Both of them agree that bondage or suffering is due to ignorance of reality and liberation is due to the right knowledge of reality. Secondly, they are also in agreement on the point that this earthly life is full of suffering and liberation which is an absolute annihilation of suffering, is the supreme end of life. Of course they differ in some points. Firstly, Nyâya develops logic and epistemology, whereas Vaiúeika develops metaphysics and ontology. Secondly, Nyâya accepts sixteen categories, while Vaiúeika accepts seven categories. Nyâya is a pluralistic logical realism, because Nyâya is concerned with the categories which are real as well as pluralistic in number. Thirdly, while Nyâya recognizes four pramânas, viz. perception, inference, comparison and verbal testimony, Vaiúeika recognizes only two pramânas, viz. perception and inference and reduces comparison and testimony to inference.




The Nyâya system defines knowledge as ‘manifestation of objects’ (arthaprakasobuddhi). Knowledge, in this system, is compared to light. Just as light illumines all the objects set before it, similarly knowledge also manifests all the objects around it. Nyâya broadly divides knowledge into two types. One is anubhava or presentative cognition and the other is smti or memory. Smti or memory is known as representative cognition.

These two types of knowledge can again be divided into valid (yathârtha) and non-valid (ayathârtha). Valid presentative knowledge is called pramâ. Valid knowledge is that type of knowledge in which we apprehend an object as it is. For example, when I perceive a snake as a snake and not as a rope, it is called valid knowledge (pramâ). My knowledge in this case of snake is certain, because I am certain about the truth of my cognition. The snake is directly presented to me as it is. But if I wrongly perceive a snake for a rope, then it is not valid. Valid presentative knowledge is divided into perception, inference, comparison and testimony. Invalid knowledge is of four kinds- memory (smiti), doubt( sashaya), error( viparyaya) and hypothetical reasoning ( tarka). Memory is not valid, because, it is always representative and never presentative. That is to say, in memory we recall an object, but the object recalled is not presented to my memory, it is representative. Doubt is not a valid source of knowledge as we are in an uncertain state in doubt. Again, error is misapprehension, because in error we perceive something wrongly. Sometimes we mistake a rope for a snake and hence such type of knowledge is erroneous, because it is not true cognition of an object. It is not ‘yatharthanubhava.’

After getting an idea about knowledge, an important question may arise at this point. The question is how it is possible for us to distinguish between true knowledge and false knowledge. The answer is that ‘knowledge is true if it corresponds to the nature of its object, otherwise it becomes false.’ Your knowledge that ‘milk is white’ is true, if milk is really white. On the other hand, your concept of the swan as black is false, since a swan is white and black colour does not really belong to the swan. Thus it is clear that true knowledge is that which corresponds to facts ( yathârtha). But false knowledge is that which does not correspond to facts (ayathârtha). Here another question may arise- how to distinguish that your knowledge of the milk as white is true and your knowledge of the swan as black is false. That is to say, how to test the truth or falsity of knowledge. True knowledge leads to successful activity ( pravttisâmarthya), but false knowledge leads to failure and disappointment ( pravttivisamvâda). Here an important point comes into light. That is, truth and falsity are the extrinsic characteristics of knowledge. They do not belong to knowledge, because, the question of truth or falsity of a thing depends upon the question of the correspondence or non-correspondence of that thing to the fact. Thus we have seen that ‘correspondence’ is the nature of truth, but successful activity is the test of truth.Therefore in Nyâya we find a realistic as well as a pragmatic approach to truth. Realistic in so far as the nature of truth is concerned and pragmatic in so far as the test of truth is concerned.


What is the distinction between Pramâ and Pramâna in Indian philosophy? Discuss

What is the difference between nature and test of truth? Discuss


1. Who was the propounder of the Nyâya System?
a) Gautama b) Vishvanâtha
2. Nyâya broadly divides knowledge into two types. True/ False
3. There are four types of invalid knowledge. True/ False.
4. Mention four kinds of invalid knowledge as stated by the Nyâya System.
5. What is Knowledge according to the Nyâya system?
6. What is the nature of truth according to the Nyâya system?
7. What is the test of truth according to the Nyâya system?


Nyâya considers perception, inference, analogy and verbal testimony to be the four kinds of valid knowledge.The Sanskrit term of the word ‘perception’ is ‘pratyaka’. Literally the term ‘pratyaka’ means what is related to the senses. The word ‘pratyaka’ may mean either of the following three things. First,it may mean the perceptual knowledge gained by sense-organs. Secondly, perceptual knowledge may mean the instrument of perceptual knowledge. Thirdly, it may mean the object of perceptual knowledge. In Nyâya system,‘pratyaka’ means the instrument of valid knowledge

Different definitions of perception have been offered by different philosophers. These definitions are given below:

1. Gautama defines perception as “non-erroneous cognition which is produced by the intercourse of the sense organs with the objects,which is not associated with a name and which is well-defined”. (Indriyarthasannikarsotpannam jnanam avayapadeshyam avyabhichari vyavasayatmakam pratyaksam, Nyaya Sûtra, 1.1.4.) . This definition of perception does not include divine and yogic perception, because these perceptions are not generated by the intercourse of the sense- organs with the objects.

2. Vishvanâtha defines perception as “ direct or immediate cognition which is not derived through the instrumentality of any other cognition.” In this definition we find that a factor of ‘ immediacy’ is present. Thus this type of perception does not require any medium. This definition therefore, includes ordinary as well as extra-ordinary perception. But it excludes inference, comparison and testimony.


In the Nyâya theory of perception, the naiyayikaka mainly divides Perception into two kinds, namely, ordinary( laukika) and extraordinary (alaukika).

Ordinary and Extra-Ordinary Perception (Laukika and Alaukika Pratyaka)

Ordinary perception is that type of perception in which the sense organs come into contact with the objects in an ordinary way. That means, an usual sense-object contact gives rise to ordinary perception. Here, we do not get any extra-ordinary medium of perception. On the contrary, extra-ordinary perception is that type of perception where there is a contact of the sense-organs with the objects not in an ordinary way, but in an extra-ordinary way. That is to say, in extra-ordinary perception, we have an extra-ordinary or unusual medium of perception. Ordinary perception is of two kinds- internal( manasa) and external (bâhya). In internal perception, mind, which is the internal organ comes into contact with the internal states and processes like pleasure, pain, desire, aversion, cognition, affection, conation etc. External perception is of five kinds—visual, auditory, tactual, gustatory and olfactory. These types of perception are brought about by the sense-organs of sight, sound, touch, taste and smell respectively. The external sense-organs are constituted of material elements of earth, water, fire, air and ether and therefore each can sense the particular quality of its element. For example, the sense organ of taste is composed of the atoms of water and perceive ‘taste’ which is the specific quality of water.

Extra-ordinary perception is of three kinds—Sâmânyalakana, Jñânalakaa and Yogaja. Let us discuss these three kinds of Perception one by one.

1. Sâmânyalakaa pratyaka: It is the perception of classes. It is the perception of the whole class of objects through its class-character as perceived in individual member of that class. For example, when we perceive a horse, we also perceive the universal horseness present in that individual horse. Here,our senses come into contact with the object, through its class-character, namely, horseness. We perceive a horse through ordinary sense-object contact. But through the perception of ‘universal horseness’ present in an individual horse, we also perceive all the individuals of that kind at all times and at all places. This perception of all the horses in this world of all times and all places is possible extra-ordinarily and through ordinary sense-object contact. This extra-ordinary perception is known as jñânalakaa pratyaka. All ‘universals’ (e.g. all the horses) in this world, according to the Naiyayikas, are perceived extra-ordinarily through sâmânyalakaa pratyaka.

2. Jñânalakaa pratyaka: The second kind of extraordinary perception is jñânalakaa pratyaka. It is the perception of an object through the previous knowledge of an object. In this type of perception the sense-organ is not in contact with the object. Here, an object is not directly presented to a sense-organ. But the object was perceived in the past and that past remembrance is retained in memory. This memory helps in cognizing the object present before us to be the object “as seen in the past”. For example, we perceive a fragrant rose from a distance and say, “ I see a fragrant rose”. But it is not possible for us to ‘see’ a fragrant rose. Because, fragrance is something which is possible for us to ‘smell’ through the nose only; it is not possible for us to ‘see’ the fragrance of a rose. When I state that “ I see a fragrant rose”, I thereby am stating that I am getting the fragrance of the rose through the visual organ of eye. Then how is it possible for us to state that I am perceiving smell through my eye? The answer is that here the visual perception of the rose gets associated with the past remembrance of the fragrance of the rose which was received in the past through the nose. The perception of the fragrant rose through the visual organ of eye, therefore is known as jñânalakaa pratyaka. This perception is also known as ‘complicated perception’ through association. Here, different sensations get associated and form one integrated perception. Some other examples of jñânalakaa pratyaka are: ‘tea looks hot’, ‘ice looks cold’ etc.

‘Anyathâkhyâtivâda’ is the Nyâya theory of error accepted by the Naiyayikakas. When we mistake a shell for a silver, the idea of silver perceived in the past is imported in memory through this extra-ordinary jñânalakaa pratyaka and is confused with the object which is directly presented to the sense-organ. Thus, the object which is directly presented to the sense-organ is confused with the object cognized in the past. When we wrongly synthesise the present object with the object of the past, error occurs. The word ‘anyathâ’ means ‘otherwise’ and ‘elsewhere’. In an erroneous perception, object presented directly is perceived otherwise and the object which was perceived in the past exists otherwise. Both of these two objects are separately real, but our synthesis of them is wrong and hence unreal.

3. Yogaja perception: The third kind of extra-ordinary perception is yogaja perception. Yogaja perception is intuitive perception of all objects of the past and the future. This intuitive power of the yogis are created by meditation ( yogaja-sannikarsa). A yogi or a mystic can perceive all objects, infinite and infinitesimal, by means of the power of meditation. Through the meditative power, yogins can perceive objects which are imperceptible to ordinary people. Yogic perception is of two kinds: yukta and yunjana. Yukta is the intuition of a yogin, who has attained union with God. Such knowledge is constant and spontaneous. But yunjana is the intuition of a yogin, who is trying constantly to attain union with God. This type of perception needs concentration.

Indeterminate and Determinate perception (Nirvikalpa and Savikalpa Pratyaka

According to another classification of the Nyâya theory of perception, perception is divided into two kinds: Indeterminate perception (Nirvikalpa pratyaka) and Determinate perception (Savikalpa pratyaka). They are only two stages of perception, namely the earlier stage of perception and the later age is an advantage stage of perception. Indeterminate perception arises immediately after the sense-object contact. It is the immediate apprehension of an object, without any determination of the name of the object or the class to which the object belongs. This type of perception is completely free from assimilation, discrimination, analysis and synthesis. It is the direct awareness of an object. For example, when we perceive a jug, we cognize the jug as a jug, we do not try to find out what is the shape of the jug, what colour do the jug has or how the jug is different from other objects etc. Here we are not concerned with the qualities of the objects. But when we try to apprehend the jug in relation to its qualities, indeterminate perception transforms into determinate perception. Here we can clearly understand that indeterminate and determinate perceptions can be differentiated only in thought, they cannot be separated in reality, because they are the two stages of the same process.


1. What is literal meaning of pratyaka according to the Nyâya System?
2. In the Nyâya theory of Perception, one classification of perception is into Ordinary and Extra-ordinary. True/ False
3. According to one classification of Perception, perception is divided into Indeterminate and Determinate. True/False
4. Ordinary perception is of five/ six kinds.
5. Extra-ordinary perception is of three kinds. True/ False
6. What are the kinds of Extra-ordinary perception? Mention them.
7. Anyathâkhyâtivâda/ Satkhyâtivâda is the theory of error in Nyâya theory of perception.


In this unit you have read about Nyâya theory of perception. From this unit you have come to know about the ‘nature of knowledge’ according to the Nyâya System. You have also learnt about nature and definition of perception. There are two ways of classifying perception. According to one division of perception, perception is divided into two kinds- Ordinary perception (laukika pratyaka) and Extra-ordinary perception (alaukika pratyaka). Ordinary perception is of two types— external (bâhya) and internal (manasa). External perception is of five kinds— visual, auditory, guastatory, tactual, olfactory. Mind is the organ which is regarded to be the internal organ of perception. Again, extra-ordinary perception is divided into three kinds—— Sâmânyalakaa pratyaksa, Jñânalakaa pratyaka and Yogaja pratyaka. On the otherhand, according to another Classification of perception, perception is of two types— Indeterminate (Nirvikalpa) and Determinate (Savikalpa) perception. Nyâya theory of error is known as Anyathâkhyâtivâda. This theory is based on jñânalakaa pratyaka.


  • Surendra Nath Dasgupta: A History of Indian Philosophy, Motilal Banarasi Publication
  • Jadunath Sinha: Indian Philosophy, Motilal Benarasi Das Publication
  • Subodh Kappor: The Systems of Indian Philosophy, Motilal Banarasi Das Publication
  • Chandradhar Sarma: A Critical History of Indian Philosophy, Motilal Banarasi Das publication
  • S. Chatterjee: An Introduction to Indian Philosophy, Motilal Benarasi Das Publication
  • S. Rdhakrishnan: Indian Philosophy, Motilal Banarasi Das Publication


I) 1. a) Gautama
2. True
3. True
4. The four kinds of invalid knowledge stated in the Nyâya system are— Memory ( smti), error (viparyaya), doubt (sashaya) and hypothetical reasoning( tarka)
5. Knowledge, according to the Nyâya system, is, manifestation of objects placed before it. In Sanskrit such type of knowledge is called ‘Arthaprakasho buddhi.
6. Correspondece or non-correspondence is the nature of truth.
7. Successful activity or failure to produce something is the test of truth.

II) 1. The literal meaning of the term ‘ pratyaksa’ is ‘what is related to the senses.’
2. True.
3. True
4. Five kinds
5. True
6. There are three kinds of Extra-ordinary perception. They are the following —— Sâmânyalakaa pratyaka, jñânalakaa pratyaka and Yogaja pratyaka.
7. Anyathâkhyâtivâda.


  1. Discuss the nature and definition of perception.
2. Describe different types of Ordinary and Extra-ordinary Perception.
3. Explain briefly Indeterminate and Determinate perception.
4. Explain the Nyâya theory of error.
5. What is pramâ? How it is different from apramâ. Mention various kinds of pramâ.
6. Distinguish between:
a. Laukika and Alaukika perception
b. Nirvikalpa and Savikalpa perception
7. Write short notes on:
a. Jñânalakaa pratyaka
b. Sâmânyalakaa pratyaka
c. Yogaja perception