Acharya Prashant clarifies that spirituality is not about believing in a divine entity or a governing power. Instead, the literal and profound meaning of spirituality is the act of knowing oneself deeply. It is an inquiry into the nature of the 'I' that everyone refers to but few understand. This 'I' is synonymous with the conscious mind or consciousness. The speaker explains that all problems are centered around this 'I'; without the ego's attachment, nothing can be perceived as a problem. Therefore, the ego itself is the root cause of all suffering and the primary disease that needs to be addressed.