आत्मन् ज्ञान

The philosophical schools associated with what we now call Hinduism all had in common respect for the authority of the Veda (‘Knowledge’), scriptures accepted as a revealed body of wisdom, cosmological information and codes of societal obligations. The textual schools that systematized disciplines derived from the Veda were the Mīmāṃsā, the Nyāya, the Vaiśeṣika, the Sāṅkhya and the various Vedānta schools . Concerned as all these schools were with correct interpretation of the Veda, it is natural that questions of language were of paramount importance in Indian philosophy. These involved detailed investigation into how subjects are to be defined and how texts are to be interpreted.
Closely related to questions of language were questions of knowledge in general and its sources. The two most important sources of knowledge that Indian philosophers discussed were sensation and inference, the theory of inference being important to the development of logic in India. Another topic about which Indian thinkers had much to say was the problem of how absences are known. Because of the importance of scriptures and religious teachers, epistemologists in India discussed the issue of the authority of texts and the question of the reliability of information conveyed through human language. The questions associated with epistemology are in Indian philosophy often closely connected with questions of human psychology.
Most schools of Indian philosophy offered not only an epistemology but also an ontology. Many posited a personal creator god or an impersonal godhead. Just how particular things come into being through creative agency or through impersonal natural laws was a matter of considerable debate. Indian thinkers also debated the precise nature of matter, the ontological status of universals, and how potentials become actualities.
In addition to epistemology and metaphysics, a third area that Indian systematic philosophers nearly always commented upon were issues concerning the nature of the human being. This included thoughts on a variety of ethical questions and the rewards for living an ethical life. While most thinkers dealt with individual ethics, some also gave attention to the question of collective behaviour and policy.

Richard Hayes: Indian and Tibetan philosophie in Routledge Encyclopedia of Philosophie