Acharya Prashant explains that the ultimate remedy for suffering is the inquiry into the self and the world. He emphasizes that all suffering originates from the world and our relationships with objects and people. By inquiring into both the subject (the 'I') and the object (the world), the duality between the two dissolves, leading to non-dual truth and freedom from both the internal ego and external world. He advises against looking for liberation in the 'beyond' and instead suggests examining one's daily life, actions, and thoughts. The speaker asserts that truth is the only method and it is accessed through surrender, which occurs when one recognizes the futility of their own cleverness and planning. This honesty about one's state may cause initial pain or disappointment, but such disappointment is considered auspicious as it leads to letting go of false hopes and entering into true spirituality.