I’m running through my shortening list of excuses, trying to reason my way out of the gaping hole somewhere inside the unmapped chambers of my heart. With your biology pragmatism, of course, you’re going to say the human heart only has four chambers, two atria and two ventricles, that pump the same amount of blood every day, every hour, every minute, keeping me alive. You’ll say that pain comes from the limbic system, and, perhaps more metaphorically, it’s all in my mind...