This is probably the edgiest post I will ever write, because I want to talk today about edge cases. Like some of the concepts I described in my post on narrative physics, this is another instance of me taking an idea from a "hard" field (science, engineering, math) and applying it to a "soft" field (political science, philosophy, literature), and this time that concept is edge cases. If you're not familiar, an edge case is an engineering term used in testing to express failure modes. For a product to be deemed effective/safe/useful, it has to be rigorously tested, and not just under "normal" conditions; it has to be exposed to the most extreme and unusual conditions that the engineers can possibly imagine it might ever conceivably experience, and tested in that environment, too. Those extreme and unusual conditions are known as edge cases, and it is very common for a product to require redesign after it has met its nominal operating conditions because it fails to account for edge cases. If only that concept were applied outside of engineering.