You have mastered Stage Four when you’re free from both gross distractions and strong dullness. Physical sensations, thoughts, memories, and emotions still arise, but they no longer draw attention away. Dullness no longer leads to drowsiness, nor causes perception of the breath sensations to grow dim or take on hypnagogic distortions. By the end of Stage Four, you can direct and sustain your attention at will. This is a unique and powerful ability.
