Acharya Prashant explains that the human mind operates on three distinct levels. The first level is the known, which is socially acceptable, organized, and artificial, much like a manicured garden designed for others' approval. This level is a facade where individuals act according to societal expectations to protect their self-image. Beneath this lies the second level, the unknown or the 'jungle,' which contains suppressed instincts, anger, and violence. This level represents the reactions that emerge without thought, often characterized by animalistic impulses. People fear this second level because it contains the 'filth' they are ashamed of, leading them to use the first level as a mask to hide their true internal state.