Chapter 48 critiques certain spiritual teachers. What specific characteristics does it identify as insufficient for being considered a Sadguru, and why is 'self-experience' presented as the ultimate qualifier?

Chapter 48 of the Sai Satcharitra meticulously outlines why certain teachers, despite their apparent knowledge, are not considered Sadgurus by the wise. The chapter lists several insufficient traits: proficiency in the Vedas or Shastras, explaining Vedanta, practicing pranayama, wearing heated marks (Taptamudra), or giving mantras without ensuring results. These are deemed 'verbally hollow' because they lack the crucial element of self-experience. As the text explains, only an experienced person can manifest the pure taste of experience. A teacher without direct experience has nothing substantial to give a disciple. Therefore, the chapter establishes that the authority to enlighten comes only from being a giver of direct, full experience, making it the ultimate and indispensable qualifier for a true Sadguru.