What are the doctrines of Vedanta?

What are the doctrines of Vedanta?

The Vedantist says, "I am He". Brahman is real and the world illusory. Even the "I" is illusory. Only the Supreme Brahman exists. But the "I" cannot be got rid of. Therefore it is good to have the feeling, "I am the servant of God, His son, His devotee."