The four Mahāvākyas, or "great sentences," are considered to be some of the most profound statements in the Upanishads, which are a collection of ancient Indian texts that form the basis of the Hindu philosophy of Vedanta. These four statements are considered to be the key to understanding the ultimate nature of reality and the self.
"Prajñānam Brahma" (Aitareya Upanishad 3.3 of the Rigveda) - "Consciousness is Brahman"
This statement asserts that the ultimate reality is consciousness, and that Brahman (the absolute reality) and the individual self (Atman) are one and the same. It suggests that the true nature of the self is pure consciousness and that the ultimate goal of spiritual practice is to realize this unity.
"Tat Tvam Asi" (Chandogya Upanishad 6.8.7) - "Thou art that"
This statement asserts that the individual self (Atman) and Brahman are identical. It suggests that the true nature of the self is identical to the ultimate reality and that the ultimate goal of spiritual practice is to realize this identity.
"Aham Brahmasmi" (Brihadaranyaka Upanishad 1.4.10) - "I am Brahman"
This statement asserts that the individual self (Atman) is identical to Brahman. It suggests that the true nature of the self is identical to the ultimate reality and that the ultimate goal of spiritual practice is to realize this identity.
"Ayam Atma Brahma" (Mandukya Upanishad 2) - "This self is Brahman"
This statement asserts that the individual self (Atman) is identical to Brahman. It suggests that the true nature of the self is identical to the ultimate reality and that the ultimate goal of spiritual practice is to realize this identity.
In conclusion, these four Mahāvākyas are considered to be the key to understanding the ultimate nature of reality and the self in the Upanishads. They assert that the ultimate reality is consciousness, and that Brahman and the individual self are one and the same. They suggest that the true nature of the self is identical to the ultimate reality and that the ultimate goal of spiritual practice is to realize this identity.