Babies seem to automatically stack their joints; that is they line their skeletal structure up perpendicular to gravity automatically. On all fours, they just know how to line their wrists up under little shoulders, or knees under hips. I have decided that they can do this because they lack the muscular strength to do anything but rely on correct alignment in relation to gravity. As Bridger sits in a most natural cobbler pose (seated with soles of feet touching, thighs splayed) I marvel at how at ease he is, at how open his hips are, and how effortlessly he sits totally erect. There is no tension in his frame - just wondrous awareness of right now.
I spent the better part of last month trying to form a hypothesis as to why babies have such natural posture, and this is what I've decided - without an ego, they have no reason to draw their shoulders forward to protect their heart, or to push the heart forward in defense. They live so completely in the present that there is no somatic repercussion to the emotional onslaught of the outside world. They are utterly authentic. It's so beautiful.
In my own practice I'm exploring moving like a baby. Initiating each movement from my sacrum, and trying to use as little muscular strength in each asana, instead relying on proper alignment and presence to find the edge in my own body - the place between ease and effort. In yoga this is known as sthirasukha. In the Yoga Sutra this is explained with an image from Indian mythology; the asana must be soft and gentle enough to serve as a couch for a god, but at the same time be strong and steady enough to support the whole earth. Another way to process this cerebrally is to rely less on the outcome of an asana, and to focus on the quality of the action. In a lot of ways I think this is how one must be to parent effectively as well.
I know a catch phrase in zen philosophy is 'beginner mind' - in my practice my phrase right now is 'baby mind, baby body'. It's been an interesting exploration - I'm curious to see how it will mature with time.