Whenever we refer to the “breath” as the meditation object, we actually mean the sensations produced by breathing, not some visualization or idea of the breath going in and out. When I direct you to observe the “breath” in the chest or abdomen, I mean the sensations of movement, pressure, and touch occurring there as you breathe in and out. When I say the “breath at the nose,” I mean the sensations of temperature, pressure, and air moving on the skin anywhere around the tip of the nose, the rim, inside the nostrils, or on the upper lip just below the nostrils.
