As an infant, the external objects which attract your attention are too far away to investigate. Your body is very small, you have almost no control over it, and the reach of your hands is less than a foot. But the objects which attract your attention the most are further away; sometimes they're across the room! They’re much too far away to be reached and the “mountain won’t come to Mohammed,” but neither yet can “Mohammed go to the mountain.” You haven’t anywhere near enough bodily control to get to the things outside your reach attracting your attention, nor enough control of your hands to investigate those that happen to be close enough to grasp.
Gradually, you begin to understand that you have to pull your attention back in. You have to start focusing on your hands because you need to learn to control them if you’re going to be able to investigate things within reach; you also need to focus inwardly in order to develop enough bodily control to get to things your eyes draw you to that are out of reach. So you focus inwardly until you learn to control your hands enough to pick up and explore things close by, and to control your body enough to get to those that aren't. But once you acquire these skills, you stop focusing inwardly. Your attention never goes back to your fundamental relations to the environment – it never goes back to breath and gravity.
Over the course of your life, you will learn many skills – you’ll learn to walk, run, and perhaps ride a bicycle; who knows, you may learn to crochet, dance the tango, play the piano, or shoot a bow and arrow. Learning any bodily skill will require initially bringing attention inward – in order to teach your body to do what it needs to do, you have to attend to it. But for all of the countless skills you may learn in life, you will attend to your body only long enough to acquire them. If you don’t make any special effort to do so, you will never continue the journey inward toward what seemed so shocking when you first emerged from your mother’s womb. The world keeps pulling your attention outward, and, unless you make a concerted effort, it never allows you to return to what it feels like to breathe and to be subject to Earth’s gravity.