are you a ghost?

Of all the discussions that Oona and I have had on our walks home from "school" (daycare), probably the most animated revolve around the physical properties of ghosts. In her mind, a ghost is almost completely defined by the absence of arms and legs. So when I suggest that her cousins are ghosts, or her mommy is a ghost, or perhaps even she is a ghost, she will instantly refute this by pointing out the presence of appendages. No, she'll say, No, I'm not a ghost. I have arms. Look, daddy. LOOK. I HAVE ARMS. I HAVE ARMS AND LEGS! At which point I remind her that it is not polite to yell in the street. And then we turn the conversation to whether or not ghosts can eat. They *do* have mouths, I point out, and watch her brain explode.