Acharya Prashant explains that the Upanishadic concept of 'Neti-Neti' (not this, not this) does not mean searching for truth, but rather refusing to grant the status of 'truth' to anything easily. He clarifies that when we label something as truth, we develop an expectation of permanence. Since worldly things are inherently impermanent, they eventually change or perish, leading to disappointment and suffering. By practicing 'Neti-Neti', one acknowledges that nothing in the material world is eternal, thereby avoiding false expectations and the resulting heartbreak.