Yoga is discussed in the ancient foundational Sutras of Hindu philosophy. The Vaiśeṣika Sūtra of the Vaisheshika school of Hinduism, dated to have been composed sometime between 6th and 2nd century BCE discusses Yoga.[note 14] According to Johannes Bronkhorst, an Indologist known for his studies on early Buddhism and Hinduism and a professor at the University of Lausanne, Vaiśeṣika Sūtra describes Yoga as "a state where the mind resides only in the soul and therefore not in the senses". This is equivalent to pratyahara or withdrawal of the senses, and the ancient Sutra asserts that this leads to an absence of sukha (happiness) and dukkha (suffering), then describes additional yogic meditation steps in the journey towards the state of spiritual liberation.
The origins of yoga are a matter of debate. There is no consensus on its chronology or specific origin other than that yoga developed in ancient India. Suggested origins are the Indus Valley Civilization (3300–1900 BCE) and pre-Vedic Eastern states of India, the Vedic period (1500–500 BCE), and the śramaṇa movement. According to Gavin Flood, continuities may exist between those various traditions:
The great positive impact of public health programs is widely acknowledged. Due in part to the policies and actions developed through public health, the 20th century registered a decrease in the mortality rates for infants and children and a continual increase in life expectancy in most parts of the world. For example, it is estimated that life expectancy has increased for Americans by thirty years since 1900, and worldwide by six years since 1990.
The early Buddhist texts describe yogic and meditative practices, some of which the Buddha borrowed from the śramaṇa tradition. The Pali canon contains three passages in which the Buddha describes pressing the tongue against the palate for the purposes of controlling hunger or the mind, depending on the passage. However, there is no mention of the tongue being inserted into the nasopharynx as in true khecarī mudrā. The Buddha used a posture where pressure is put on the perineum with the heel, similar to even modern postures used to stimulate Kundalini. Some of the major suttas that discuss yogic practice include the Satipatthana sutta (Four foundations of mindfulness sutta) and the Anapanasati sutta (Mindfulness of breathing sutta).
"...[T]here is the cultivation of meditative and contemplative techniques aimed at producing what might, for the lack of a suitable technical term in English, be referred to as 'altered states of consciousness'. In the technical vocabulary of Indian religious texts such states come to be termed 'meditations' ([Skt.:] dhyāna / [Pali:] jhāna) or 'concentrations' (samādhi); the attainment of such states of consciousness was generally regarded as bringing the practitioner to deeper knowledge and experience of the nature of the world." (Gethin, 1998, p. 10.)