Advaita Vedanta can be translated as "the path to experiencing the truth." Jnana Yoga - the yoga of wisdom or knowledge - is part of Advaita Vedanta. It is considered by some to be the most difficult of all the yogic paths.
To experience jagat without recognizing it as illusion, is considered by Jnana yogis to be living in a dream-like state. In order to achieve Self-realization, yogis must recognize that jagat is illusory because this illusion is what prevents the understanding of the true Self.
This unreality is sometimes called maya and causes humans to falsely perceive themselves as separate from Brahman. Maya makes people identify themselves as disconnected parts of what is in reality a whole.