Acharya Prashant explains that to understand the Guru, one must first understand the disciple. He defines the Guru as the one who leads an individual from darkness to light. The disciple is essentially a bundle of tendencies and a sense of incompleteness that seeks fulfillment through the body, mind, and the world. Because humans are deeply identified with the physical body and believe that completeness can be achieved through sensory experiences, they can only relate to and learn from another physical form. This is why a living, physical Guru is necessary for most people.