According to Crangle, some researchers have favoured a linear theory, which attempts "to interpret the origin and early development of Indian contemplative practices as a sequential growth from an Aryan genesis",[note 4] just like traditional Hinduism regards the Vedas to be the ultimate source of all spiritual knowledge.[note 5] Thomas McEvilley favors a composite model where pre-Aryan yoga prototype existed in the pre-Vedic period and its refinement began in the Vedic period.
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.
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.
^ "Sidang Media – Fatwa Yoga". Islam.gov.my. Archived from the original on 6 January 2009. Retrieved 5 September 2010. Quote: The Fatwas of Religious Council in Islamic affairs on Yoga. After carefully studied various reports and factual data, the Council unanimously agreed that this ancient India religious teachings, which involves physical and mental exercises, are Hinduism in nature known as wahdat al-wujud philosophy (oneness of existence; the realization of identity between the Self in man, Atman; and the Divine, BRAHMAN: ‘Brahman is all, and Atman is Brahman'). It is prohibited (haram) for Muslims to practice it.
Malaysia's top Islamic body in 2008 passed a fatwa, prohibiting Muslims from practicing yoga, saying it had elements of Hinduism and that its practice was blasphemy, therefore haraam. Some Muslims in Malaysia who had been practicing yoga for years, criticized the decision as "insulting." Sisters in Islam, a women's rights group in Malaysia, also expressed disappointment and said yoga was just a form of exercise. This fatwa is legally enforceable. However, Malaysia's prime minister clarified that yoga as physical exercise is permissible, but the chanting of religious mantras is prohibited.