Indian philosophy

Indian philosophy consists of philosophical traditions of the Indian subcontinent. A traditional Hindu 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.

There are six major (āstika) schools of Vedic philosophy—Nyaya, Vaisheshika, Samkhya, Yoga, Mīmāṃsā and Vedanta—and five major heterodox (nāstika or sramanic) schools—Jain, Buddhist, Ajivika, Ajñana, and Charvaka. The āstika group embraces the Vedas as an essential source of its foundations, while the nāstika group does not. However, there are other methods of classification; Vidyaranya for instance identifies sixteen schools of Indian philosophy by including those that belong to the Śaiva and Raseśvara traditions.

The main schools of Indian philosophy were formalised and recognised chiefly between 500 BCE and the late centuries of the Common Era. Some schools like Jainism, Buddhism, Yoga, Śaiva and Vedanta survived, but others, like Ajñana, Charvaka and Ājīvika did not.

Ancient and medieval era texts of Indian philosophies include extensive discussions on ontology (metaphysics, Brahman-Atman, Sunyata-Anatta), reliable means of knowledge (epistemology, Pramanas), value system (axiology) and other topics.