The bits of anatomy and physiology I'm learning -- "sound-byte science" is the accurate phrase one of my teachers, in an unguarded moment, let fall -- have impressed me above all with how much the body alters, how fluid and changeable it is, how much tissue is being torn down and rebuilt every day. That understanding dovetails nicely with Buddhist contemplations about the impermanence of the body.
Every moment we are creating our bodies. Every moment we sit, as we are right now, dear reader, with our shoulders hunched and immobile, our necks thrust forward, and our heads craned up, our arms poised like a mantis's over mouse and keyboard, we're issuing building instructions. Make a body, we're saying, whose breast can't open, and whose shoulders can't drop. Make a body that holds still by dint of continual muscular effort and tension, rather than by relaxation and balance. Make a body that responds to stimulation by isometric contraction, rather than by motion.
We yearn for our bodies to change, as if the problem were that they were rigid and unalterable. The problem, on the contrary, is that they are all too plastic. They give us, heroically, as long as they are able, exactly what we ask for.