Hindu philosophy refers to philosophies, world views and teachings that emerged in ancient India. These include six systems (shad-darśana) – Sankhya, Yoga, Nyaya, Vaisheshika, Mimamsa and Vedanta.In Indian tradition, the word used for philosophy is Darshana. This word comes from the Sanskrit root drish (to see, to experience). Darshana can be translated as 'Point of view'.
These are also called the Astika (orthodox) philosophical traditions and are those that accept the Vedas as an authoritative, important source of knowledge. Ancient and medieval India was also the source of philosophies that share philosophical concepts but rejected the Vedas, and these have been called nāstika (heterodox or non-orthodox) Indian philosophies. Nāstika Indian philosophies include Buddhism, Jainism, Cārvāka, Ājīvika, and others.Scholars have debated the relationship and differences within āstika philosophies and with nāstika philosophies, starting with the writings of Indologists and Orientalists of the 18th and 19th centuries, which were themselves derived from limited availability of Indian literature and medieval doxographies. The various sibling traditions included in Hindu philosophies are diverse, and they are united by shared history and concepts, same textual resources, similar ontological and soteriological focus, and cosmology. While Buddhism and Jainism are considered distinct philosophies and religions, some heterodox traditions such as Cārvāka are often considered as distinct schools within Hindu philosophy.Hindu philosophy also includes several sub-schools of theistic philosophies that integrate ideas from two or more of the six orthodox philosophies, such as the realism of the Nyāya, the naturalism of the Vaiśeṣika, the dualism of the Sāṅkhya, the non-dualism and knowledge of Self as essential to liberation of Advaita, the self-discipline of yoga and the asceticism and elements of theistic ideas. 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. The ideas of these sub-schools are found in the Puranas and Āgamas.Each school of Hindu philosophy has extensive epistemological literature called pramāṇaśāstras, as well as theories on metaphysics, axiology, and other topics.