A common fallacious form of argument is that known as the "motte and bailey," also sometimes called the "bait and switch," though the archaic term "motte and bailey" is more evocative for those of us who aren't engaged either in retailing products or in fishing as a regular matter. The term "motte" suggests a strong defensive position (not to be confused with a "moat," though obviously related -- we'll get to that). The motte is the raised earthwork in front of a castle. It may have a wooden palisade on its crest. The "bailey" is a pleasant and less militarized zone, perhaps a courtyard or market, outside of the protection of the motte. A moat, or perhaps a dry ditch, might exist protecting the whole motte-and-bailey complex. The idea is that the whole complex is defensible against small numbers of foes. But against a larger more determined attack, when a raid becomes a battle, the bailey might have to be aban...