Classical yoga incorporates epistemology, metaphysics, ethical practices, systematic exercises and self-development techniques for body, mind and spirit.[144] 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.[240] This is done by stilling one's thought waves (citta vritti) and resting in pure awareness of puruṣa.
Buddhist yoga encompasses an extensive variety of methods that aim to develop key virtues or qualities known as the 37 aids to awakening. The ultimate goal of Buddhist yoga is bodhi (awakening) or nirvana (cessation), which is traditionally seen as the permanent end of suffering (dukkha) and rebirth.[note 20] Buddhist texts use numerous terms for spiritual praxis besides yoga, such as bhāvanā ("development")[note 21] and jhāna/dhyāna.[note 22]
One of the best known early expressions of Brahmanical Yoga thought is the Yoga Sutras of Patanjali , the original name of which may have been the Pātañjalayogaśāstra-sāṃkhya-pravacana (c. sometime between 325 - 425) which some scholars now believe included both the sutras and a commentary.[129] As the name suggests, the metaphysical basis for this text is the Indian philosophy termed Sāṃkhya. This atheistic school is mentioned in Kauṭilya's Arthashastra as one of the three categories of anviksikis (philosophies) along with Yoga and Cārvāka.[130][131] The two schools have some differences as well. Yoga accepted the conception of "personal god", while Samkhya developed as a rationalist, non-theistic/atheistic system of Hindu philosophy.[132][133][134] Sometimes Patanjali's system is referred to as Seshvara Samkhya in contradistinction to Kapila's Nirivara Samkhya.[135] The parallels between Yoga and Samkhya were so close that Max Müller says that "the two philosophies were in popular parlance distinguished from each other as Samkhya with and Samkhya without a Lord."[136]