The Earth is a sphere, which means there’s no easy way to project it onto a flat surface. One of the methods used to project the Earth’s surface on the map results in certain places (such as Greenland) to be stretched to huge sizes, sometimes appearing as big as Africa (look up “Mercator map”). The joke here is that while we expect him to make a comment about the map’s projection, he instead comments on how Greenland on the physical map is only a few inches, as opposed to its actual size.
This is especially disturbing when you consider that, for most of us, most of our knowledge consists of such secondhand, literally-interpreted abstractions. And then this bogus knowledge is firmly validated by our similarly deluded peers.
It highlights the role of interpretation in our social epistemology. A dozen people can cite the same argument, all nodding their heads wisely, coming to a good and reasonable agreement, yet hold a dozen different meanings