 Initial work on these entries was supported by a fellowship from Stanford Humanities Center during the academic year 2002–03. Several versions of these entries have been greatly helped by a number of research assistants, including Jason Rosensweig, Edwin Etieyibo, John Kardosh, Courteney Crump, Paolo Verdini, Júlia Diniz e Carvalho, and Tyler Mathiassen. Thanks also go to the editors and staff at the Stanford Encyclopedia of Philosophy. Work on these entries have been supported by grants from the Social Sciences and Humanities Research Council of Canada, for which I am very grateful.