Acharya Prashant explains that self-inquiry, specifically the question "Who am I?", is the foundation of all spirituality and Vedanta. He clarifies that this question is not asked by the pure self, which is non-dual and complete, nor by insentient objects, but by the ego. The ego, being in a state of ignorance and discontentment, questions its own existence and the source of its thoughts and feelings. Since the ego is both the questioner and the respondent, it must raise its level of consciousness and attention to answer the query. This process of seeking the root of one's existence forces the ego to change and eventually disappear, as the questioner and the respondent are ultimately the same. In practical terms, asking "Who am I?" or "Where is this coming from?" in moments of suffering, such as anger or jealousy, acts as a sword that cuts through the state of mind. By investigating the source of an emotion, the individual dissociates from it, effectively tearing away the mask of the ego. Acharya Prashant emphasizes that this method requires absolute honesty and a genuine desire for liberation. One must be willing to say "I am not this" (Neti Neti) before asking "Who am I?". If one is still attached to the pleasures of their current identity, the inquiry becomes a superficial exercise. Ultimately, the question does not lead to a verbal answer but to the dissolution of the suffering questioner.