Classical yoga incorporates epistemology, metaphysics, ethical practices, systematic exercises and self-development techniques for body, mind and spirit. Its epistemology (pramana) and metaphysics is similar to that of the Sāṅkhya school. The metaphysics of Classical Yoga, like Sāṅkhya, is mainly dualistic, positing that there are two distinct realities. These are prakriti (nature), which is the eternal and active unconscious source of the material world and is composed of three gunas, and the puruṣas (persons), the plural consciousnesses which are the intelligent principles of the world, and are multiple, inactive and eternal witnesses. Each person has a individual puruṣa, which is their true self, the witness and the enjoyer, and that which is liberated. This metaphysical system holds that puruṣas undergo cycles of reincarnation through its interaction and identification with prakirti. Liberation, the goal of this system, results from the isolation (kaivalya) of puruṣa from prakirti, and is achieved through a meditation which detaches oneself from the different forms (tattvas) of prakirti. This is done by stilling one's thought waves (citta vritti) and resting in pure awareness of puruṣa.
Jain yoga has been a central practice in Jainism. Jain spirituality is based on a strict code of nonviolence or ahimsa (which includes vegetarianism), almsgiving (dana), right faith in the three jewels, the practice of austerities (tapas) such as fasting, and yogic practices. Jain yoga aims at the liberation and purification of the self (atma) or soul (jiva) from the forces of karma, which keep all souls bound to the cycle of transmigration. Like Yoga and Sankhya, Jainism believes in a multiplicity of individual souls which bound by their individual karma. Only through the reduction of karmic influxes and the exhaustion of one's collected karma can a soul become purified and released, at which point one becomes an omniscient being who has reaches "absolute knowledge" (kevala jnana).
^ Mangano, Kelsey M.; Sahni, Shivani; Kiel, Douglas P.; Tucker, Katherine L.; Dufour, Alyssa B.; Hannan, Marian T. (February 8, 2017). "Dietary protein is associated with musculoskeletal health independently of dietary pattern: the Framingham Third Generation Study". The American Journal of Clinical Nutrition. 105 (3): 714–722. doi:10.3945/ajcn.116.136762. PMC 5320406. PMID 28179224 – via ajcn.nutrition.org.
The origins of yoga have been speculated to date back to pre-Vedic Indian traditions; it is mentioned in the Rigveda,[note 1] but most likely developed around the sixth and fifth centuries BCE, in ancient India's ascetic and śramaṇa movements.[note 2] The chronology of earliest texts describing yoga-practices is unclear, varyingly credited to Upanishads. The Yoga Sutras of Patanjali date from the first half of the 1st millennium CE, but only gained prominence in the West in the 20th century. Hatha yoga texts emerged sometimes between the 9th and 11th century with origins in tantra.
Pre-philosophical speculations of yoga begin to emerge in the texts of c. 500 – c. 200 BCE. Between 200 BCE and 500 CE, philosophical schools of Hinduism, Buddhism, and Jainism were taking form and a coherent philosophical system of yoga began to emerge. The Middle Ages saw the development of many satellite traditions of yoga. Yoga came to the attention of an educated western public in the mid 19th century along with other topics of Indian philosophy.
^ For instance, Kamalashila (2003), p. 4, states that Buddhist meditation "includes any method of meditation that has Enlightenment as its ultimate aim." Likewise, Bodhi (1999) writes: "To arrive at the experiential realization of the truths it is necessary to take up the practice of meditation.... At the climax of such contemplation the mental eye … shifts its focus to the unconditioned state, Nibbana...." A similar although in some ways slightly broader definition is provided by Fischer-Schreiber et al. (1991), p. 142: "Meditation – general term for a multitude of religious practices, often quite different in method, but all having the same goal: to bring the consciousness of the practitioner to a state in which he can come to an experience of 'awakening,' 'liberation,' 'enlightenment.'" Kamalashila (2003) further allows that some Buddhist meditations are "of a more preparatory nature" (p. 4).
In 2009, the Council of Ulemas, an Islamic body in Indonesia, passed a fatwa banning yoga on the grounds that it contains Hindu elements. These fatwas have, in turn, been criticized by Darul Uloom Deoband, a Deobandi Islamic seminary in India. Similar fatwas banning yoga, for its link to Hinduism, were issued by the Grand Mufti Ali Gomaa in Egypt in 2004, and by Islamic clerics in Singapore earlier.
If the meaning of yoga is understood as the practice of nirodha (mental control), then its goal is "the unqualified state of niruddha (the perfection of that process)", according to Baba Hari Dass. In that context, "yoga (union) implies duality (as in joining of two things or principles); the result of yoga is the nondual state", and "as the union of the lower self and higher Self. The nondual state is characterized by the absence of individuality; it can be described as eternal peace, pure love, Self-realization, or liberation."
Modern yoga is a physical activity consisting largely of asanas, often connected by flowing sequences called vinyasas, sometimes accompanied by the breathing exercises of pranayama, and usually ending with a period of relaxation or meditation. It is often known simply as yoga, despite the existence of multiple older traditions of yoga within Hinduism where asanas played little or no part, some dating back to the Yoga Sutras, and despite the fact that in no tradition was the practice of asanas central.
The spiritual sense of the word yoga first arises in Epic Sanskrit, in the second half of the 1st millennium BCE, and is associated with the philosophical system presented in the Yoga Sutras of Patanjali, with the chief aim of "uniting" the human spirit with the Divine. The term kriyāyoga has a technical meaning in the Yoga Sutras (2.1), designating the "practical" aspects of the philosophy, i.e. the "union with the supreme" due to performance of duties in everyday life.