 Convention-based theories are widely proposed for many social phenomena, including traffic rules, etiquette, laws, language, norms, institutions, morality, gender, codes of dress, and religion—as well as geometry, logic, truth, and necessity (see, among many others, Quine 1936, Lewis 1969, Schiffer 1972, Carter &amp; Patterson 1982, Gilbert 1983, Kekes 1985, Sugden 1986, Sidelle 1989, Friedman 1995, Lagerspetz 1995, Young 1996, Bicchieri 2005, Bickhard 2008, Schotter 2008, Marmor 2009, Azzouni 2014, Guala 2016).