The differentiation of the seer (the one who sees) and the objects seen is called viveka. What is seen and who is the seer?
If the eye is the seer the objects around is the seen. Similarly, to the mind, the eye is seer and the sense organ of vision is the seen. For true consciousness, which is the seer, the mind becomes the seen. The true consciousness is the ultimate seer which experiences without the help of other entity, this true consciousness alone is the witness. Lamp doesn't need another lamp to prove its presence.
In darkness a beam of light is required for us to know if a person exists, but we need no light to know our own presence. Consciousness is self-aware of its existence. But this true consciousness has a reflected consciousness which is ego that is projected due to the reflecting medium called the mind. The mind is a subtle form of energy that has no consciousness of its own but acts as a conscious entity due to ego. This ego is limited consciousness and acts as the observer, knower and the experienced. Identification of the reflected consciousness with the world and getting attached to the likes and dislikes of it is called samsara. The only way to overcome ego is to shun doer-ship. The ego is the "i" ness present in mind where thoughts, feelings and experiences circle. Once this reflected consciousness is withdrawn from the mind and merged with the true consciousness -- then the non attachment to the body and the mind is achieved. We require a proficient guru and uninterrupted sadhana to know which this reflected consciousness is.
The king announced a reward of 1,000 gold coins for anyone who found the diamond necklace that his daughter lost. A beggar was walking along a polluted river. He saw a spark in the river and when he looked close he saw the diamond necklace. He decided to try and fetch it so that he could get the reward.
He put his hand in the filthy river to grab the necklace, but somehow could not get it. He took his hand out and looked again and the necklace was still there. He tried again. But strangely, he still missed the necklace! He came out and started walking away, feeling depressed. Then again, he saw the necklace, right there. This time he was determined to get it. He decided to plunge into the river. Although it was disgusting, he plunged in and searched everywhere for the necklace. Just then, a sadhu who was walking by saw him, and asked him what the matter was. The beggar didn't want to share anything with the sadhu, thinking he might take the necklace and get the reward.
Being compassionate, the sadhu again asked the beggar to tell him the problem and promised that he would not tell anyone. The beggar gathered some courage and decided to put some faith in the sadhu. He told him about the necklace and how he tried and tried to get it, but kept failing.
The sadhu then told him that perhaps he should try looking upward, toward the branches of the tree, instead of in the filthy river. The beggar looked up and was surprised to see the necklace dangling on the branch of a tree. He had been trying to capture a mere reflection of the real necklace all the time.