Observer consciousness

Here is an excerpt from The Power of Now: A Guide to Spiritual Enlightenment by Eckhart Tolle:

So when you listen to a thought, you are aware not only of the thought but also of yourself as the witness of the thought. A new dimension of consciousness has come in. As you listen to the thought, you feel a conscious presence - your deeper self - behind or underneath the thought, as it were. The thought then loses its power over you and quickly subsides, because you are no longer energizing the mind through identification with it. This is the beginning of the end of involuntary and compulsive thinking.When a thought subsides, you experience a discontinuity in the mental stream - a gap of “no-mind.” At first, the gaps will be short, a few seconds perhaps, but gradually they will become longer. When these gaps occur, you feel a certain stillness and peace inside you. This is the beginning of your natural state of felt oneness with Being, which is usually obscured by the mind. With practice, the sense of stillness and peace will deepen. In fact, there is no end to its depth. You will also feel a subtle emanation of joy arising from deep within: the joy of Being.

You can experience what Eckhart Tolle is talking about by choosing not to identify with your thoughts. You have thoughts but you're not your thoughts.