Hindu philosophy

Hindu philosophy or Vedic philosophy is the set of philosophical systems that developed in tandem with the first Hindu religious traditions during the iron and classical ages of India. In Indian philosophy, of which Hindu philosophy is a prominent subset, the word used for philosophy is Darshana (Sanskrit: दर्शन; meaning: "viewpoint or perspective"), from the Sanskrit root 'दृश' (drish) meaning 'to see, to experience'.

The schools of thought or Darshanas within Hindu philosophy largely equate to the six orthodox schools: the āstika (Sanskrit: आस्तिक) schools, defined by their acceptance of the Vedas, the oldest collection of Sanskrit texts, as an authoritative source of knowledge. Of these six, Samkhya (सांख्य) is the earliest school of dualism; Yoga (योग) combines the metaphysics of Samkhya with meditation and breath techniques; Nyaya (न्याय) is a school of logic emphasising direct realism; Vaisheshika (वैषेशिक) is an offshoot of Nyaya concerned with atomism and naturalism; Mimamsa (मीमांसा) is a school justifying ritual, faith, and religious obligations; and Vedanta (वेदान्त) contains various traditions that mostly embrace nondualism.

The Indian philosophical landscape during the ancient and medieval periods also produced philosophical systems that share many concepts with the āstika traditions, yet at the same time reject or oppose several central Vedic concepts, such as Ātman, or interpret them in their own way. These have been called nāstika (heterodox or non-orthodox) philosophies, and they include: Buddhism, Jainism, Charvaka, Ajivika, and others. These nāstika schools of thought are thus regarded as Indian but almost never as Hindu. Western scholars have debated the relationship and differences within āstika philosophies and with the nāstika philosophies, starting with the writings of Indologists and Orientalists of the 18th and 19th centuries, based on limited availability of Indian literature and medieval doxographies. The various sibling traditions included in Indian philosophies are diverse and are united by: shared history and concepts, textual resources, ontological and soteriological focus, and cosmology. Some ambiguity arises from the word Hindu being an exonym historically used as a geographical and cultural identifier for people living in the Indian subcontinent, sometimes regardless of their beliefs.

Hindu philosophy also includes several sub-schools of theistic philosophies that integrate ideas from two or more of the six orthodox philosophies. Examples of such schools include: Pāśupata Śaiva, Śaiva siddhānta, Pratyabhijña, Raseśvara and Vaiṣṇava. Some sub-schools share Tantric ideas with those found in some Buddhist traditions, which are nevertheless found in the Puranas and the Āgamas. Each school of Hindu philosophy has extensive epistemological literature called Pramana, as well as theories on metaphysics, axiology, and other topics.