The importance of his answer and the care with which he framed it comes at the very end of the clip. Without specifying a context he cannot answer the question

The importance of his answer and the care with which he framed it comes at the very end of the clip. Without specifying a context he cannot answer the question. Leading up to that one is made to understand that without limiting the question to a particular context, an infinite regress is unavoidable. Brilliant, well articulated point that most people don't think about.