Brahman is the ultimate reality in the Upanishads. It is the source of all existence and is beyond time, space, and causation.

Brahman and Atman are the same. The Upanishads teach that the individual soul (Atman) is identical with the universal soul (Brahman).

The goal of human life according to the Upanishads is to attain moksha, which is liberation from the cycle of birth and rebirth.

Brahman is infinite and eternal. It is beyond time, space, and causation.

Atman is individual and immortal. It is the individual soul that is identical with Brahman.

Brahman is the source of Maya. Maya is the illusion that creates the appearance of the world.

Maya is unreal. It is the illusion that creates the appearance of the world.

The goal of spiritual practice according to the Upanishads is to realize the unity of Brahman and Atman.

The term 'neti neti' means 'not this, not this'. It is used to negate all attempts to define Brahman.

The term 'tat tvam asi' means 'you are that'. It is used to express the identity of Brahman and Atman.

The term 'aham brahmasmi' means 'I am Brahman'. It is used to express the identity of Brahman and Atman.

The term 'sarvam khalvidam brahma' means 'all this is Brahman'. It is used to express the unity of Brahman and the world.

The term 'prajnanam brahma' means 'consciousness is Brahman'. It is used to express the identity of Brahman and consciousness.

The term 'sat-chit-ananda' means 'existence-consciousness-bliss'. It is used to describe the nature of Brahman.