Nyaya – the Science of Logic and Expediency

The four Upangas or appendices are Mimamsa – interpretation of Vedic texts (Purvamimamsa & Uttaramimamsa, Nyaya – logic (Nyaya-Vaisheshika), Puranas – old history (18 Mahapuranas, 18 Upapuranas and Itihasapuranas), Dharma Shastras - codes of conduct (Smritis Dharma sutras).
The Nyaya Shastra, also known as Tarka Shastra, is a shastra whose chief instrument of conviction is deduction. In Nyaya and Vaisheshika, the world and soul are deemed to exist separate from Ishvara which is actually the Dvaitic (Dualistic) Siddhanta.
Both the schools of thought prove the existence of atma with the help of inference (anumana) and are recognized as systems of the same status (samanatantra). Yet the two schools of thought reveal certain distinctive features maintaining their identity. The Naiyayikas recognize sixteen categories while the Vaisheshikas only six.
Nyaya shastra reasoned out why this world was created. Causes are of two kinds – Nimitta and Upadana. Nimitta is the person / Ishvara who is cause of this world. Upadana is the things or atoms which created the world. Likewise, purusha does not at all indulge in the act of creation, Prakriti derives its power, under the influence of Purusha, to create something out of itself. Ishvara does not interfere in any way as Nimitta. Prakriti thus manifests itself as creation. This is the doctrine of Sankhayas. This is also the theory of transformation.
The Vaisheshika system maintains that the atoms are not created by God, but are co-eternal with Him. The power, however, which combines two atoms and makes aggregates of atoms, comes from God. According to this system ether, time, space, Atman or Self, and mind or manas, are eternal substances of nature. Mind or manas is described as infinitely small, like an atom (anu); but it is distinct from Atman or Self, which is vast (vibhu). Although mind and Atman or Self are eternal, still they are innumerable. The Self or Atman is distinct from the senses, and possesses nine qualities, such as knowledge, will, desire, happiness, etc.
Exponents of Nyaya Shastra -
The Nyaya School grounded in Gautama Akshapada’s Nyaya sutra and the Vaisheshika School grounded in Kanada’s Vaisheshika Sutra developed in parallel until around 10th, 11thand 12th century and later merged to form a new school–Syncretic school or Nyaya -Vaisheshika school.
The term Vaisheshika is derived from the Sanskrit word vishesha which means the characteristic that distinguishes a particular thing from all other things
Fundamentals of Nyaya –

1. Nyaya School –

The Nyaya School was founded by the sage Gautama. The Nyaya shastra discusses the fundamental Truth through the aid of four devices viz. Pratyaksha (direct perception), Annumana (indirect perception, proof arising from deduction), Upamana (Simile or example) and Shabda (Sound). In Pratyaksha, experience is done through sense organs.
 
Nyaya system begins with the enumeration of sixteen padartha has, or subjects for discussion: (1) pramana, proof or means of knowledge; (2) prameya, or objects of knowledge; (3) samshaya, or doubt; (4) prayojana, motive or purpose; (5) dristanta, example or instance; (6) siddhanta, or determined truth; (7) avayava, syllogism or premisses; (8) tarka, reasoning or confutation; (9) nirnaya, or conclusion; (10) vada, or argumentation; (11) jalpa, or sophistry; (12) vitanda, objection; (13) hetvabhasa, or fallacies; (14) chhala, quibble or perversion; (15) jati, or false analogies; and, (16) nigrahasthana, or unfitness for arguing.
 

1. Perception takes place through six senses according to which perception has been classified into two -Internal and External. In internal perception, manas (the mind) which is the internal organ comes into contact with the psychical states and processes like cognition, affection, desire, pain, pleasure, aversion etc.

 
External perception, on the other hand, takes place when the five sense organs of sight, sound, touch, taste and smell come into contact with the external objects.
 
Perception is further divided into two namely nirvikalpaka (indeterminate) and savikalpaka (determinate). Bare sensation or simple apprehension is nirvikalpaka perception; while the perceptual judgment or relational apprehension is savikalpaka perception. Indeterminate perception refers to the awareness of an object which is non-relational and nonjudgmental; whereas determinate perception is the awareness of an object with its quality (genes).
 
Extra-ordinary perception is classified into three: samanyalakshana, jnanalakshana and yogaja. The perception of generic character comes under samanyalakshana. For example, seeing a cow, one immediately becomes aware of the samanya (class essence) of it i.e., the gotva (the cowness). Jnanalakshana is that type of knowledge of a thing previously experienced. E.g., Fragrance of jasmine. Yogaja is the intuitive perception of all object’s past, distant and future due to some super normal powers generated in the mind by meditation. Thus, perception is the most important Pramana.

1. Anumana (Inference) is the second significant source of knowledge in Nyaya philosophy. It is both a source of cognition and a way of reasoning. As a source of cognition, it produces inferential knowledge. It creates awareness of an object through the consideration of some mark, which is invariably connected with the object of the knowledge. For example, if there is smoke, fire must be there.
2. Upamana (Simile) is the third source of knowledge. It is produced by the knowledge of resemblance or similarity. A man who has never seen a wild cow comes across one in the forest and recognizes it remembering the words of the forester as a wild cow resembles a domestic cow. This knowledge he derives from upamana.
3. Shabda (Verbal Testimony) is considered as a valid source of knowledge in Nyaya. It is the statement of a trustworthy person and consists in understanding its meaning. His words will come under the purview of the verbal testimony. The trustworthy people help others to avoid evils and attain good.  There are two kinds of testimonies - Laukika and Alaukika. The authors of the Vedas are considered aptas (reliable).

 

1. Vaisheshika School –

Kanada, in his Vaisheshika Sutra states that all objects of knowledge or all real, comes under padartha. According to him there are only six Padarthas viz., Dravya (substance), Guna (quality), karma (action), Samanya (generality), Vishwesh (particularity), and Samavaya (inherence). Although he has not mentioned about Abhava (non-existence) as separate Padartha, it is observed that Kanada takes due cognizance of Abhava as a Padartha.

1. Dravya has been divided into nine types – Prithvi (earth), Apas (water), Tejas (fire, light), Vaayu (air), Akasha (space), Kaala (time), Dik (direction), Atma (soul) and manas (mind). The sky or space, with a single Guna of sound, Vayu which in addition to sound has touch; Agni or fire which in addition to sound and touch, has Roopa or form visible to the eye, water having Rasa or savour and earth which has smell in addition to the four gunas – these are the Pancha Bhootas or five elements. These are matters which represent the Pancha Bhootas on whom depend the gunas for the discernment.
2. The Vaisheshika School accepts only two independent sources of valid knowledge (pramana) i.e., Perception (Pratyaksha) and Inference (Anumana). The Vedas are a valid source of knowledge, and are based on the perception (pratyaksha) of wise sages. Perception is dependent on sense organs that include both external and internal. Internal perception is due to conjunction of the Self with the internal organ. External perception arises due to the contact of the five sense organs with their concerned objects. External perception is of five types; olfactory, gustatory, visual, cutaneous and auditory. Vaisheshika admits yogic perception also.
3. Vaisheshika holds that Anuman is the knowledge of probandum derived from the knowledge of the proband. It is derived from the mark from which the existence of the probandum is inferred as its effect or cause. For instance, from smoke, the existence of fire is inferred. Thus, mark is the means of inference in Vaisheshika and it is based on the relations of causality, conjunction etc.

Science in the Nyaya Philosophy -

1. There are nine substances: (1) earth; (2) water; (3) light; (4) air; (5) ether; (6) time (kala); (7) space (desha); (8) self (Atman); and (9) mind (manas). These substances cannot exist without qualities, of which there are seventeen: colour, taste, smell, touch, number (that by which we perceive one or many), extension or quantity, individuality, conjunction, priority, posteriority, thought, pleasure, pain, desire, aversion, and will. The substances are affected by five kinds of action: (1) upward motion, (2) downward motion, (3) contraction, (4) expansion, (5) movement from one spot to another. All the objects of knowledge must be either substance, quality, or motion.
2. The first four substances are non-eternal as aggregates, but are made up of minute invisible atoms (anus) which are eternal. They exist as inorganic and organic matter, or as instruments of sense-perceptions. Kanada describes atoms (anu) as indivisible particles of matter which possess no visible dimensions. These atoms are of two (anus). It is called dvyanu, or molecule which is still invisible. The aggregate of three molecules or double atoms forms a trasarenu, which has visible dimension. These aggregates of composite atoms are destructible, while single atoms are indestructible by nature. How remarkable it is to see that the conception of atoms and molecules arose in India centuries before the time of Empedocles and Democritus! And the latest atomic theory of European science has not in any way surpassed that of ancient India.