"I can track what the mind is. I can even understand what the intellect is doing and a sort of understanding, causal state," he says. "But notice, it will be a luminous void. Why? Because you will find no objective reality corresponding to this Atman Brahman." He continues: "This luminosity, this emptiness, this no atman Brahman will be revealed to you the consciousness".
Swami Sarvapriyananda teaches the Katha Upanishad, one of India's most revered texts which is also a part of the Vedas. It is a collection of philosophical poems representing a conversation between the sage Naciketas and Yama (god of death). They discuss the nature of Atman, Brahman and Moksha(liberation).