Ātman and Brahman

Two lessons have set up one question. Brahman is what everything rests on. Ātman is what a person most deeply is. What is the relation between them?

This is not a minor puzzle at the edge of the tradition. It is the central disputed question of Vedānta, and the argument you are about to meet has run for centuries and is still live.

The Upaniṣads state the relation in a handful of very short declarations. Later tradition gathered four of them and called them mahāvākyas, "great sayings" — one from each Veda.

tat tvam asi — "you are that" (Chāndogya, from the Sāmaveda) ahaṃ brahmāsmi — "I am Brahman" (Bṛhadāraṇyaka, from the Yajurveda) ayam ātmā brahma — "this self is Brahman" (Māṇḍūkya, from the Atharvaveda) prajñānaṃ brahma — "consciousness is Brahman" (Aitareya, from the Ṛgveda)