Pramāṇa (Sanskrit: प्रमाण) literally means "proof", "that which is the means of valid knowledge". It refers to epistemology in Indian philosophies, and encompasses the study of reliable and valid means by which human beings gain accurate, true knowledge. The focus of Pramana is the manner in which correct knowledge can be acquired, how one knows or does not know, and to what extent knowledge pertinent about someone or something can be acquired. Ancient and medieval Indian texts identify six pramanas as correct means of accurate knowledge and truths:
The different schools of Vedanta have historically disagreed as to which of the six are epistemologically valid. For example, while Advaita Vedanta accepts all six pramanas, Vishishtadvaita and Dvaita accept only three pramanas (perception, inference and testimony).
Advaita considers Pratyakṣa (perception) as the most reliable source of knowledge, and Śabda, the scriptural evidence, is considered secondary except for matters related to Brahman, where it is the only evidence. In Vishistadvaita and Dvaita, Śabda, the scriptural testimony, is considered the most authentic means of knowledge instead.