Turning Toward the End
The last part of the Ānāpānasati instructions pivots away from tranquility and clarity of heart toward insight and letting go. The fourth tetrad starts with observing impermanence, then unfolds through a natural progression of fading away, cessation, and letting go. The gist of the whole sequence is made plain: with a heart stabilized in happiness and embodied focus, see how everything passes away and cannot be clung to.
A lot is said about letting go, but much of it ends up lodging only in the psychological realm: that we should let go of obsessing about things we cannot change. This is true enough, and useful, but by implying that it's good to obsess about things we think we can change, it leaves intact the majority of our clinging. The wisdom offered in the Ānāpānasati is subtler and more radical. It's not about letting go of any specific thing that's troubling your heart, but about seeing how everything—what you love and what you hate, without preference—crumbles by itself, almost immediately.
Letting go, the last step in the sequence, is not a cultivation the way steps 3-12 were. You don't practice letting go. You practice "observing" it. It's an insight, not a discipline. Letting go is happening whether you like it or not, and if you don't figure it out in a titrated way while you're alive, you'll get it in a big, difficult dose at death. Taken this way, the clinging we so suffer from is really just a fancy way of saying fantasizing. We're thinking and feeling a lot about the past and future even though most of what we obsess about is impossible.
All experiences self-destruct. They are impermanent, they fade away, they cease, and they slip out of whatever grasp our heart tries to hold them with. When the heart knows this completely, a strange well-being becomes strong in us,
