[wpietri]

This is something that I don't think you will be able to understand until you have tried it enough to see what others see in it. There are many activities like that.

The point of focusing on breathing is not to do the breathing in place of your automatic breathing. It is to pay attention to that automatic breathing.

Contemplating the central limit theorem is a complex activity. Where does contemplation of that truly end? It is easy to follow the mind's natural tendency to become distracted. You think about related math. You think about your math professor that first talked about it. You think about unrelated math. You think about practical applications.

The breath is simple. You observe the breath going in and out. When your mind it on something else, you return it to the breath. Over and over. You don't have to consider anything: if you attend to something other than the sensation of the breath, you've wandered off.