Earlier versions of this article were presented at the Arché Philosophical Research Centre in St. Andrews, at the Harvard Kennedy School's Safra Center for Ethics, at the Harvard Humanities Center's Cognitive Theory and the Arts Seminar, and at the 2009 Rocky Mountain Ethics Congress in Boulder, Colorado (where my commentator was Daniel Demetriou). Joshua D. Greene was kind enough to attend both sessions at Harvard and to offer clarifications and replies. For written comments on earlier drafts, I am indebted to Jacob Beck, Carol Berker, Tyler Doggett, Frances Kamm, Christine Korsgaard, Seana Shiffrin, Judith Jarvis Thomson, and Hasko Vonkriegstein (on behalf of the moral psychology reading group at Toronto University). For helpful comments and discussion, many thanks as well to Arthur Applbaum, Sharon Berry, Tim Button, Yuri Cath, Colin Chamberlain, Norman Daniels, Daniel Demetriou, Tom Dougherty, Matti Eklund, Nir Eyal, Michael Frazer, Johann Frick, Micha Glaeser, Ned Hall, Ulrike Heuer, Jonathan Ichikawa, Ole Koksvik, Arnon Levy, Louis Menand, Oded Na'aman, Dilip Ninan, François Recanati, Simon Rippon, T. M. Scanlon, Susanna Siegel, Alison Simmons, Leo Ungar, Manuel Vargas, Alex Voorhoeve, Glen Weyl, Liane Young, and Elia Zardini. Finally, I am grateful to the Editors of Philosophy & Public Affairs for a number of extremely helpful suggestions.