Adi Shankaracharya |
According to Adi Shankaracharya, the founder of Advaita Vedanta, and the originator of the monastic lineage to which Sivananda Yoga belongs, it is the Yoga of knowing the difference between the Atman (the individual soul) and Brahman (the Absolute or Universal Soul).
There are lots of famous Nyayas or stories which help to illustrate the difference between the real and the unreal.
Some of the most famous are, The Snake and the Rope, The Gold and the Ornament, and the Sun and the Pot.
According to Krishna in the Bhagavad Gita (13.3) it the knowledge of the kshetra, or the field and the knower of the field.