children have an amazingly intuitive grasp of complicated legal rules. And a freakishly inventive ability to improve on them. My first criminal-law professor taught us everything we needed to know about criminal intent by reminding us of the kindergartener's hierarchy of self-defense. First: "I didn't do it." Second: "I did it but I didn't mean to." Third: "I meant to do it but I didn't plan it." And finally: "I was upset at the time and I promise I won't do it again."