At my eclipse watch party, I overheard a woman ask "is it the sun or the moon that is causing the shadow?" And at first I thought "what a stupid question," but then I asked myself whether she was actually asking a much deeper philosophical question, like "if a tree falls in the forest..." I mean, what actually casts a shadow - the light source, or the thing in front of the light source? Or is it really both?
In reality, she probably wasn't sure if the dark thing was the sun or the moon.