I love this analogy! First, I think it is true. For example, the more one knows about economics, the more potential research projects one can see. Second, it is an optimistic take on one’s growing sense of ignorance: if the island is close to circular, knowledge is growing with the square of the diameter of the island, while the boundary with ignorance is only growing in direct proportion to the diameter of the island. Third, it points up how titles such as The End of Science (by John Horgan) betray a lack of an extensive enough knowledge of science to clearly see the length of the shoreline of ignorance.