I have to disagree with his first example. He says "X is in a category whose archetypal member has certain features".

The first example is "Abortion is murder". He then says, "If you define murder as 'killing another human being', then abortion is technically murder."

The problem is that in this case, his "if" applies to roughly 56% of the US population, as they define murder that way. In other words, he needs to select a category that has a unanimous agreement about its features instead of selecting a category that has a myriad of definitions and then choosing his own favorite definition and its corresponding archetypes.