 For helpful suggestions on this entry (and the previous version), I thank Dorothea Baur, George Brenkert, Jason Brennan, Matt Caulfield, David Dick, Anca Gheaus, Keith Hankins, Edwin Hartman, Laura Hartman, Lisa Herzog, David Jacobs, Woon Hyuk Jay Jang, Peter Jaworski, Xavier Landes, Chris MacDonald, Emilio Marti, Dominic Martin, Pierre-Yves Néron, Eric Orts, Katinka Quintelier, Sareh Pouryousefi, Amy Sepinwall, Kenneth Silver, Abraham Singer, Alejo José G. Sison, Cindy Stark, Chris Surprenant, Kevin Vallier, and Hasko von Kriegstein.