Abstract: Experiments of Living Constitutionalism urges that the Constitution should be interpreted so as to allow both individuals and groups to experiment with different ways of living, whether we are speaking of religious practices, family arrangements, political associations, civic associations, child-rearing, schooling, romance, or work. Experiments of Living Constitutionalism prizes diversity and plurality; it gives pride of place to freedom of speech, freedom of association, and free exercise of religion (which it would protect against the imposition of secular values); it cherishes federalism; it opposes authoritarianism in all its forms. While Experiments of Living Constitutionalism has considerable appeal, my purpose in naming it is not to endorse or defend it, but as a thought experiment and to contrast it to Common Good Constitutionalism, with the aim of specifying the criteria on which one might embrace or defend any approach to constitutional law. My central conclusion is that we cannot know whether to accept or reject Experiments of Living Constitutionalism, Common Good Constitutionalism, Common Law Constitutionalism, democracy-reinforcing approaches, moral readings, originalism, or any other proposed approach without a concrete sense of what it entails – of what kind of constitutional order it would likely bring about or produce. No approach to constitutional interpretation can be evaluated without asking how it fits with the evaluator’s “fixed points,” which operate at multiple levels of generality. The search for reflective equilibrium is essential in deciding whether to accept a theory of constitutional interpretation.