All the six darśanas (Hindu systems of philosophy) accept certain basic sources or means of knowledge, known as ‘pramāṇas’, upon which they further develop their theories.
These pramāṇas vary from a minimum of three to a maximum of six. They are as follows.
PRATYAKṢA (direct or immediate perception) has two stages of development. As soon as the sense-organ comes into contact with the sense-object, there is a general awareness of it, as something existing. This is called nirvikalpaka-pratyakṣa. In the next stage, all the details will be noted in the light of past experience. This is savikalpa-pratyakṣa.
ANUMĀNA (inference) gives us the knowledge of a thing indirectly, when we see some liṅga or sign invariably connected with the original. For instance, by seeing smoke on a yonder hill, we can infer that there is fire there (even though we do not see it directly) since it is known from previous observations and experience that smoke is invariably associated with fire.
UPAMĀNA (comparison) is another source of knowledge. On seeing a rat, one recollects that it is like the mouse he had seen earlier. He then comes to know that the remembered mouse is like the perceived rat. This type of knowledge comes through upamāna.
ŚABDA (verbal testimony) is the next source of knowledge. The Mīmāṁsā Darśana pays the greatest attention to this since it has to justify the undisputed authority of the Vedas.
The words of a reliable person are believed to be true. This is called āptavākya.
Verbal testimony, however, is of two types: pauruṣeya (personal, same as āptavākya) and apauruṣeya (impersonal). The second denotes the Vedas since they were not created by any human agency. The Vedas are supremely authoritative since they are the ‘Book of Commandments’ and also give us authentic know-ledge of the unseen and the unknown truths. Again, their main purport and purpose lies in propagating sacrificial rites.
The Vedas are eternal, not as the printed Book nor as the orally transmitted mantras but as the eternal teachings contained in them. These teachings are conveyed through the ṛṣis or sages in every age.
Since the Vedas are mainly concerned with giving commands (= vidhi) about the yāgas or sacrificial rites and other associ-ated rituals, only those sentences containing such commands as expressed through the verbs couched in ‘vidhiliṅ’ (imperative mood as in ‘svargakāmo yajeta,’ ‘One desirous of attaining heaven should sacrifice!’) and other forms should be taken as authoritative and the rest as aids to it. Such verbs have an innate power of urging the hearer to do the sacrifice. This is called ‘bhāvanā’. The urge contained in the Vedic words is known as ‘śābdī-bhāvanā’ (śabda = word). On hearing it, the person who hears it, gets the urge to perform it. This secondary urge is named ‘ārthībhāvanā’ (artha = utility, useful activity).
All this depends upon the correct understanding and interpretation of the Vedic sentences. For this, the Mīmāṁsā gives six steps: upakrama (beginning); upasaṁhāra (concluding); abhyāsa (repetition for the sake of emphasis); apūrvatā (not being known earlier by any other means); phala (utility); arthavāda (mere eulogy) and upapatti (logic and reasoning).
Once the correct meaning is thus ascertained, the command may be implemented.
ARTHĀPATTI (postulation or presumption) is the necessary supposition of an unperceived fact which alone can explain an anomaly satisfactorily. For instance, if a person is noticed to be getting fat even though he does not eat during the day, it can safely be presumed that he is secretly eating at night! Knowledge obtained by arthāpatti is distinctive since it cannot be got by any other means.
ANUPALABDHI (non-perception) has also been accepted as a source of know-ledge since it gives the immediate cognition of the non-existence of an object. If it is found that a jar which had been kept on a table earlier, is not perceived now, its non-existence is cognized.