Vedanta teaches that what shines as "I" is satyam, Brahman (ever-existent, ever-present, Infinite Consciousness) and that while "I" is self-luminous, self-existing, independent of of the body-mind-sense complex and the universe, yet this universe which includes this body-mind-complex is not separate from "I".
Pujya Swami Dayananda Saraswati makes this simple to understand by pointing out that "B can be A but A is not B". He says:
"The physical body can be I, but I am not the physical body. See the truth of this – B can be A but A need not be B. Consider an actor A who takes on the role of the beggar B now. Where the beggar stands the actor stands; at the same time as he stands, there is a distance. The distance is not physical. B's problems and privations are not A's problems. He congratulates himself on doing a good job – shedding real tears. Others too congratulate him. The congratulations are all because there is a distance between B and A. What is the distance? B is A. But A is not B. That is the distance caused by the knowledge of svarupa. A is A all the way. A can identify with the role B, can write new scripts etc. He can make up for the missing lines of the fellow who is cast with him in the drama. At the same time, he never misses out A. This is a very important thing, because all this is Vedanta. 'Matsthani sarva bhutani na caaham teshu-avasthitah – everything is me but I am not anyone of them' (Gita 9.4).'
Our problem is that B is A and A is B. Suppose the actor thinks he is a beggar, we saw the fellow has gone mad. If there is a visitor from another planet where everyone is enlightened, where B is A and A is not B, he will think that this entire planet is a mental asylum. We do not sympathize with ourselves in the same way because all the others too are in the same boat. All of us in fact deserve sympathy. We have our own norms of normailty and decide what is normal – the one who knows himself. all others are abnormal." (Swami Dayananda – A Verse from Mundaka Up.)