It was founded by Gautam who was also the founder of ancient Indian logic. So, Nyaya is also called the science of reasoning and critical study. According to it, objects of knowledge exist independently of the knower, knowledge or mind while ideas and feelings depend upon the mind. Valid knowledge is definite and unerring and non-reproductive experience
of an object. Knowledge is true if it corresponds to facts otherwise it is false. It accepts four
ways of knowing – Perception, Inference, Verbal testimony and Comparison.
Perception – It is immediate cognition which is produced by sense-object contact. For instance, if one sees a table, this is a contact of one’s senses with the table and one is sure that the object is a table. It may be ordinary or extraordinary.
- Ordinary perception – In this, there is a sense-object contact. It is of 6 types – visual, auditory, tactual, gustatory (taste), olfactory (smell) and mental.
- Extraordinary perception – In this, there is no sense-object contact. It is of three kinds:
- Perception of classes – The sense by which we see an object also gives us knowledge of the class of that object.
- Perception by Complication – For instance, ice looks cold and the stone looks hard. Modern psychologicsts like Wundt and Ward have accepted perception by complication.
- Intuitive perception of the Yogis – Perfect yogis intuitively perceive all objects and even past objects.
According to another perspective, there are two modes of perception. They are:
- Indeterminate and indefinite perception – It is a kind of bare sensation. Something is sensed but one fails to say anything definitely, it is indeterminate perception.
- Determinate perception – In this, the character of an object of perception is cognized. Indeterminate perception precedes determinate perception.
Inference – It defined as a process of knowing something through the instrumentality or medium of a mark (Linga) that is invariably related to it. There are two types of inference:
- Inference for oneself – It does not need any formal statement of inference
- Inference for others– It must be stated in the form of five propositions which are as follows;
- There is fire on the hill (Asserted fact).
- Because there is smoke on the hill (Reason).
- Where there is smoke, there is fire. E.g. Cooking (Universal proposition)
- There is the same type of smoke on the hill (Application).
- There is fire on the hill (Conclusion).
Verbal Testimony – It is testimony of a trustworthy person – one who knows the truth and communicates it correctly. The communicator or the speaker must be both competent and honest. According to Nyaya, the Vedas are the valid source of supra sensible knowledge because their author is the all-knowing God.
Comparison – It is generally about the connection between a name and a thing.
Remember the earlier example of wild cow.