According to Zimmer, Yoga philosophy is reckoned to be part of the non-Vedic system, which also includes the Samkhya school of Hindu philosophy, Jainism and Buddhism: "[Jainism] does not derive from Brahman-Aryan sources, but reflects the cosmology and anthropology of a much older pre-Aryan upper class of northeastern India [Bihar] – being rooted in the same subsoil of archaic metaphysical speculation as Yoga, Sankhya, and Buddhism, the other non-Vedic Indian systems."[note 6]
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. 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. 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. Sometimes Patanjali's system is referred to as Seshvara Samkhya in contradistinction to Kapila's Nirivara Samkhya. 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."
Just as there was a shift from viewing disease as a state to thinking of it as a process, the same shift happened in definitions of health. Again, the WHO played a leading role when it fostered the development of the health promotion movement in the 1980s. This brought in a new conception of health, not as a state, but in dynamic terms of resiliency, in other words, as "a resource for living". 1984 WHO revised the definition of health defined it as "the extent to which an individual or group is able to realize aspirations and satisfy needs and to change or cope with the environment. Health is a resource for everyday life, not the objective of living; it is a positive concept, emphasizing social and personal resources, as well as physical capacities". Thus, health referred to the ability to maintain homeostasis and recover from insults. Mental, intellectual, emotional and social health referred to a person's ability to handle stress, to acquire skills, to maintain relationships, all of which form resources for resiliency and independent living. This opens up many possibilities for health to be taught, strengthened and learned.