Is There a Good Explanation?

The reach of a good explanation is determined by what it is explaining. It applies to my cat and to no other cats. So Yes, reach is a property of a specific category of explanations those explanations that Apply to multiple entities. The way to generate wealth is logically entailed by how to generate knowledge Which is a epistemology. And political theories would come into that as well. But I'm sure you could put in more chapters.