This is Tolle’s way of saying you must begin the practice of Mindfulness. When you notice with unconditioned awareness—which means non-judgment, just bare attention—you are shifting your center from the duality of thought to the unity of awareness. All negativity of the mind comes from the mind being split into two poles or viewpoints: the I and the IT. Resistance is felt as negativity from mild irritation to panic and anger.
This tension is the gap between the two poles if I and IT, myself as the center viewpoint and myself as an object of my own viewpoint. When this duality that is our consciousness jams up, it freezes myself into an IT. Stage fright is a good example of this. I see myself as an object through the eyes of the audience, and I lose my center. I’m stuck in the objective self as an IT. I’m a deer in the headlights.
Being aware of this tension as a mental operation from an impartial awareness restores unity, because the pure Seeing is undivided. The self as Awareness is not the operating system of the conscious mind which driven by language and thinking. Awareness is not thinking. Awareness is just space in which thinking occurs and creates the separation of mind into two poles that is our discontent. Awareness is always Now.