What is the difference between feeling and knowing the breath?
When you start to be aware of your breathing in the present moment you will lose track of where you exactly are. The perceptions of inbreath and outbreath, beginning, middle and end disappear. It is just breath happening, that's all. This is natural because you are starting to simplify your perception of the breathing, which in turn energises your mindfulness. This is the point where you will feel the joy and happiness (piti & sukha) arising together with the breath. The joy is coming from the mental experience of the breathing (the knowing with the mind), not the physical aspect (the feeling with the body). The body is fading away more and more at this stage in meditation.
(This short video clips was extracted from the Q&A sessions of the 9-day meditation retreat at Jhana Grove in July 2023 led by Ajahn Brahm. If you would like to view the entire retreat here is the KZfaq playlist: • 2023 July | 9 Day Retr... )