Pramana means “means of knowledge”. In respect of any knowledge three things are present. They are called Prameya, Pramata and Pramana respectively. Prameya is the object of knowledge, Pramata is the knower and Pramana is the means of knowledge. When Pramata in the right state of mind employs right Pramana in respect of a Prameya, right knowledge, Prama, arises; otherwise there is only delusion or wrong knowledge, Brama. As per Advaita Vedanta philosophy there are six Pramanas which we employ consciously or unconsciously to gain the knowledge of various things we come across. They are Pratyaksha, Anumana, Upamana, Arthapathi, Anupalabdhi, and Sabda. Let us see each one of them in a little more detail.
Pratyaksha (Perception) - This stands for direct, immediate cognition. This can be external and internal. The external perception implies cognition of sense objects through our sense organs. The internal perception means the direct & immediate cognition of emotions like pain, pleasure etc., and knowledge or ignorance of various objects etc. in our minds. External perception arises from the interaction of five senses with worldly objects. Each of our five sense organs has a unique and exclusive field of application: In the visual field, eyes have the unique capability to give information and knowledge of colours and forms and of all things visual. Similarly, ears have the sole and exclusive right in the field of sound, nose in the field of smell and fingers in the field of touch. All the five sense organs work as a single team and provide complementary information/knowledge of objects that we encounter, and they do not work at cross-purposes. In direct perception the knowledge is extremely clear but its scope is very limited. What we can directly see not only constitutes an extremely small iota of the wide spectrum of things existing in this universe, but many a times that which is directly cognized is far from truth. But this is the most important and common tool at individual level to obtain knowledge in an unfamiliar field.
Anumana (inference) – Anumana literally means ‘knowing after’. It means the method by which knowledge is derived from another knowledge. So the knowledge thus gained is not direct, immediate and is gained from the prior knowledge of invariable relationship between two things. On the basis of the earlier direct knowledge the present knowledge is deduced. For example we have the direct knowledge from kitchen that smoke arises from fire and that where there is smoke invariably fire is also there as its cause. So when we see smoke coming from a distant hill we deduce that there must be fire in the hill causing the smoke. This is inferential knowledge or the logical deduction. In this case Vyapthi, the universal statement of invariable concomitance, is; ‘Where there is fire there is smoke.’ On this basis we make the Anumana that there must be a fire in the distant hill when smoke is Prathyaksha in the distant hill. Thus Anumana is made on the basis of Pratyaksha based on Vyapthi
Upamana (Comparison) – Upamana means comparison and analogy. Upamana is the process by which the knowledge of B is gained from the perception of B’s similarity to A, which has been noted elsewhere. The subject of comparison is formally called upameyam, the object of comparison is called upamanam, while the attribute(s) are identified as samanya. For example when a person going to Australia is told that Dingo is a wild dog found in Australian outback, and he goes to an outback area and finds a creature similar to dog in the wild, he by comparison has the knowledge of that as Dingo. Upamana is a distinct means of knowledge, and is not clubbed under Anumana.
Arthapathi (Postulation) - Arthapathi means postulation, supposition or presumption of a fact. It is knowledge arrived at by circumstantial implication. The classic example of this method of knowledge is: a fat person says that he never eats in the day, then we can easily postulate that he eats in the night, for the simple reason that without this assumption his fatness & also his getting fatter cannot be explained. Arthapathi can either be from what is seen or from what is heard.
Anupalabdhi (Non-apprehension) - Anupalabdhi literally means ‘non-perception’. Non-existence of a thing is apprehended by its non-perception. By not seeing a jar on a table one knows that it is not there. We use this method of knowledge also very often, and this is evident from statements like : ‘There is no teacher in the class-room’, There is no sound here’, ‘This flower has no fragrance’ etc. It is different from Anumana as there is no concomitant relationship between non-perception and non-existence, as in the case of non-perception in the dark. However, it is to be noted that if a thing would have been perceived under given circumstances, but not perceived, then only it is Anupalabdhi.
Sabda (Verbal testimony) – Sabda Pramana is verbal testimony which is also called ‘apta-vakya’ (statement of a trust-worthy person’), and agama (authentic word). Hiriyanna explains Sabda Pramana as a concept which means reliable expert testimony. A verbal statement conveying valid knowledge must have an authentic source which must be free from defects. Only a competent person possessed of knowledge can impart accurate knowledge. Such a knowledge needs no verification, unless of course there is doubt about its reliability. It is man’s most potent instrument for transmitting and gaining knowledge. Books, magazines, newspapers, radio, TV, phones etc. all use or depend on words
Advaita Vedanta accepts all the above six as valid Pramanas while Visishtadvaita and Dvaita subsets of Vedanta school accept only Pratyaksha, Anumana and Sabda as valid Pramanas. Vaiseshika school considers only Pratyaksha and Anumana as valid Pramanas, while Nyaya school accepts four Pramanas viz. Pratyaksha, Anumana, Upamana and Sabda as valid. Sankhya and Yoga schools rely on the same three Pramanas as Dvaita and Visishtadvaita.