The Muṇḍaka Upaniṣad, from the Atharva Veda, distinguishes between higher knowledge (para vidyā), which leads to realization of Brahman, and lower knowledge (apara vidyā), which covers rituals and worldly learning. Using vivid imagery, it describes the Self as the imperishable reality, like two birds on the same tree—one eating the fruits (the individual soul) and the other simply witnessing (the supreme Self). It emphasizes renunciation, devotion, and direct knowledge of Brahman as the path to liberation.