Acharya Prashant addresses a question about nihilistic thoughts and the desire to abandon the material world. He begins by expanding the definition of what is material. Not only is the visible, external world material, but even the thoughts within one's head are material. He explains that thoughts cannot exist without the material brain, nor can they exist without a material object to think about. Therefore, thought itself is a material phenomenon. Consequently, having thoughts about abandoning the material world is a material act, and the thinker itself is a material entity. A materialist is someone deeply identified with the material, and a perpetual thinker is, by this definition, a materialist. If one truly wishes to shun the material, the starting point must be the material within the head—thought. The saints advised against relying on the material world because it is untrustworthy and ever-changing. Acharya Prashant points out that this applies even more so to our thoughts, which are far more fleeting and unreliable than the external world. The material inside (thought) is more intimate and thus more dangerous and difficult to detach from than the material outside. The solution is to stop taking the world and the self, the thinker, personally. This involves understanding that the person you believe yourself to be is a fiction within an impersonal, ancient game. He further distinguishes between 'bad thought' and 'good thought'. Bad thought is rooted in and reinforces memory, leading to conclusions that block further knowing. Good thought, or wisdom, acts as a cleansing agent. It works against itself to remove the filth of other thoughts from the mind and then dissolves, leaving behind a state of silent, open awareness. Wisdom is not another conclusion but a realization that is open and available to knowing. The goal is not to replace bad thoughts with good ones but to use good thought to arrive at a state of silent, objective observation of all internal and external phenomena.