The distinction I'm making with that example is between asking "What do I mean by 'motion'?", which looks at the person's understanding of the word in detail (and there isn't much useful understanding to be found in their mind if they don't already understand mechanics); and asking "What causes me to wonder about motion?", which points to the stuff that is moving, and motivates studying this moving stuff in detail, asking more specific questions about the way in which it moves.