The six orthodox (astika) systems of Hindu philosophy that accept the authority of the Vedas, traditionally grouped into three pairs, as opposed to the heterodox (nastika) schools of Buddhism, Jainism and Charvaka.
- Samkhya: founded by Kapila; dualism of Purusha (consciousness) and Prakriti (matter); the oldest system, originally non-theistic.
- Yoga: associated with Patanjali (the Yoga Sutras); practical discipline of meditation and the eight limbs (ashtanga) to control the mind; paired with Samkhya.
- Nyaya: founded by Gautama (Akshapada); a school of logic and epistemology, stressing valid means of knowledge (pramanas).
- Vaisheshika: founded by Kanada; atomic theory, classifying reality into categories (padarthas); paired with Nyaya.
- Mimamsa (Purva Mimamsa): founded by Jaimini; upholds Vedic ritual and the authority of the karma-kanda (action portion).
- Vedanta (Uttara Mimamsa): based on the Upanishads and the Brahma Sutras of Badarayana; sub-schools include Shankara's Advaita (non-dualism), Ramanuja's Vishishtadvaita and Madhva's Dvaita.
School-to-founder matching (Samkhya-Kapila, Yoga-Patanjali, Nyaya-Gautama, Vaisheshika-Kanada, Mimamsa-Jaimini, Vedanta-Badarayana) is a standard objective question, as is the astika versus nastika distinction.
Charvaka, Buddhism and Jainism are nastika (do not accept Vedic authority) and lie outside the six; "nastika" here means rejecting the Veda, not atheism, since Samkhya itself was non-theistic yet orthodox.
Six orthodox darshanas in three pairs: Samkhya-Yoga, Nyaya-Vaisheshika, Mimamsa-Vedanta.