"The house is going to fall over"

I was sitting at my desk watching Caleb playing in the backyard when he told me that "The house is going to fall over." So I said, "Oh, why do you think that? It looks like it's okay to me."
It turns out he had noticed that the shadow of the house on the back lawn had moved since the last time he had been out, so he thought the house was slowly falling over.