Samkhya or Sankya (ˈsɑːŋkjə; sāṃkhya) is a dualistic orthodox school of Hindu philosophy. It views reality as composed of two independent principles, Puruṣa ('consciousness' or spirit) and Prakṛti (nature or matter, including the human mind and emotions).
Puruṣa is the witness-consciousness. It is absolute, independent, free, beyond perception, above any experience by mind or senses, and impossible to describe in words.
Unmanifest Prakriti is matter or nature. It is inactive, unconscious, and is a balance of the three guṇas (qualities or innate tendencies), namely sattva, rajas, and tamas. When Prakṛti comes into contact with Purusha this balance is disturbed, and Prakriti becomes manifest, evolving twenty-three tattvas, namely intellect (buddhi, mahat), ego (ahamkara), mind (manas); the five sensory capacities known as ears, skin, eyes, tongue and nose; the five action capacities known as hasta, pada, bak, anus, and upastha; and the five "subtle elements" or "modes of sensory content" (tanmatras), from which the five "gross elements" or "forms of perceptual objects" (earth, water, fire, air and space) emerge, in turn giving rise to the manifestation of sensory experience and cognition.
Jiva ('a living being') is the state in which purusha is bonded to Prakriti. Human experience is an interplay of the two, Purusha being conscious of the various combinations of cognitive activities. The end of the bondage of Purusha to Prakriti is called liberation or kaivalya (isolation).
Samkhya's epistemology accepts three of six pramanas ('proofs') as the only reliable means of gaining knowledge, as does yoga. These are pratyakṣa ('perception'), anumāṇa ('inference') and śabda (āptavacana, meaning, 'word/testimony of reliable sources'). Sometimes described as one of the rationalist schools of Indian philosophy, it relied exclusively on reason.
While samkhya-like speculations can be found in the Rig Veda and some of the older Upanishads, some western scholars have proposed that Samkhya may have non-Vedic origins, and developed in ascetic milieus.