What is Baba's fundamental philosophical teaching regarding the concept of oneness versus duality?

Baba's core philosophical teaching, as detailed in Chapter 14, is that the Essence within one's own body is the very same Essence that permeates the entire universe. He emphasizes that surrendering to this universal Essence allows one to understand and experience oneness. Conversely, holding onto the concept of manifoldness or duality—the intellect that establishes difference—is described as pure ignorance that leads to the cycle of birth and death. Baba teaches that to achieve peace and realize one's true nature, one must turn away from this ignorance and see the single, unbroken essence in everything.