Pramana

Pramana (Sanskrit: प्रमाणम्; IAST: Pramāṇam) literally means "proof" and "means of knowledge". One of the core concepts in Indian epistemology, pramanas are one or more reliable and valid means by which human beings gain accurate, true knowledge. The focus of pramana is how correct knowledge can be acquired, how one knows, how one does not know, and to what extent knowledge pertinent about someone or something can be acquired.

While the number of pramanas varies widely from system to system, many ancient and medieval Indian texts identify six pramanas as correct means of accurate knowledge and attaining to the truth. Three of these are almost universally accepted: perception (pratyakṣa), inference (anumāna), and "word" (śabda), meaning the testimony of past or present reliable experts. The other three pramanas are more contentious: comparison and analogy (upamāna); postulation or derivation from circumstances (arthāpatti); and non-perception, or proof from absence (anupalabdhi). Each of these are further categorized in terms of conditionality, completeness, confidence, and possibility of error.

The various schools of Indian philosophies vary on how many of these six pramanas are epistemically reliable and valid means to knowledge. For example, the Charvaka school of the Śramaṇa tradition holds that only one (perception) is a reliable source of knowledge, Buddhism holds that two (perception, inference) are valid means, Jainism holds three (perception, inference and testimony) as valid, and the Mimamsa and Advaita Vedanta schools of Hinduism hold that all six pramanas are useful and can be reliable means to knowledge. The various schools of Indian philosophy have debated whether one of the six forms of pramana can be derived from another and the relative uniqueness of each.