Sure, set/costume design is different from directing, but they fall under the same umbrella of having an interest in making movies. James Cameron is not a polymath for the same reason someone who gets a Nobel in physics and chemistry is not a polymath. If someone gets a Nobel in literature and physics, that's being a polymath. Your music example also isn't great. I, and several other people, know how to do a wide variety of dances--square, Irish folk dancing, salsa, waltz, hip hop, lyrical, and so on. It does not make us polymaths. The differences within a discipline are pretty big, true, but the difference between disciplines supersedes those. Someone who programs and dances is jumping a much greater distance than someone who goes from ballet to hip hop.
You seem like a talented and energetic person, so kudos to you, and this discussion is ultimately about semantics, which is uninteresting. I still think you misunderstand what breed of intellectual the article is talking about, though.
You seem like a talented and energetic person, so kudos to you, and this discussion is ultimately about semantics, which is uninteresting. I still think you misunderstand what breed of intellectual the article is talking about, though.