Among the six Indian philosophies Sankhya and Yoga are closely related. Sankhya holds that there are two fundamental realities of matter and spirit (Prakruti and Purusha). It explains how the process of srishti (evolution) of the world begins from Prakruti.

The yoga system accepts the Sankhya philosophy as it has no metaphysic of its own. The yoga thus using the tools of the Sankhya epistemology explains how to isolate Purusha from Prakruti. This is somewhat the reverse process of the evolutionary course – a journey back to the source. Mind control is the first lesson one needs to learn before setting out for the return journey.

A sadhaka (practitioner of yoga) must necessarily be in a state of niramaya (disease free). Only in a body that is sound, a mind that is sound could dwell. As Charaka, ancient Indian scholar of Ayurveda, observes, the human being is a congregation of the five elements plus the sixth one called Chetana (spirit). Ayurveda addresses such a human entity. A healthy person alone could traverse the lofty mountain of para vidya – the knowledge of the Absolute says the scholars of India. Hence health is all important.