Indian philosophy consists of philosophical traditions of the Indian subcontinent. The philosophies are often called darśana, meaning "to see" or "looking at." Ānvīkṣikī means “critical inquiry” or “investigation." Unlike darśana, ānvīkṣikī was used to refer to Indian philosophies by classical Indian philosophers, such as Chanakya in the Arthaśāstra.
A traditional Vedic classification divides āstika and nāstika schools of philosophy, depending on one of three alternate criteria: whether it believes the Vedas as a valid source of knowledge; whether the school believes in the premises of Brahman and Atman; and whether the school believes in afterlife and Devas. (though there are exceptions to the latter two: Mimamsa and Samkhya respectively).