 The author thanks Ben Caplan, Michael Glanzberg, Robbie Hirsch, Greg D’amico, Judith Tonheuser, Robert May and the reading group Synners at OSU for extremely helpful comments and observations. Thanks to the OSU reading group Synners for suggestions that were invaluable additions to Section 4.1. Thanks to Paul Saka for detailed comments and helpful discussion that helped me produce the first revision of the entry. Thanks to Jeff Pelletier for very helpful suggestions that helped a great deal with the second revision.