section_path: Indian philosophy/Orthodox schools
section_name: Orthodox schools
paragraph_text: Orthodox schools
  
  The principal Indian philosophical schools are classified as either orthodox or heterodox – āstika or nāstika – depending on one of three alternate criteria: whether it believes the Vedas are 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.
  
  There are six major schools of orthodox Indian Hindu philosophy — Nyaya, Vaisheshika, Samkhya, Yoga, Mīmāṃsā and Vedanta, and five major heterodox schools— Jain, Buddhist, Ajivika, Ajñana, and Cārvāka. However, there are other methods of classification; Vidyaranya for instance identifies sixteen schools of Hindu Indian philosophy by including those that belong to the Śaiva and Raseśvara traditions.
  
  Each school of Hindu philosophy has extensive epistemological literature called Pramana -sastras.
  
  In Hindu history, the distinction of the six orthodox schools was current in the Gupta period "golden age" of Hinduism. With the disappearance of Vaisheshika and Mīmāṃsā, it became obsolete by the later Middle Ages, when the various sub-schools of Vedanta (Dvaita "dualism", Advaita Vedanta "non-dualism" and others) began to rise to prominence as the main divisions of religious philosophy. Nyaya survived into the 17th century as Navya Nyaya "Neo-Nyaya", while Samkhya gradually lost its status as an independent school, its tenets absorbed into Yoga and Vedanta.