The Politics of Incommensurability: A Value Pluralist Approach to Liberalism and Democracy

In this dissertation, I advance a new interpretation of the meaning and political implications of Isaiah Berlin's theory of value pluralism. My argument focuses on two puzzles within the literature on value pluralism: first, value pluralist political theorists advance a variety of differing political views on an ostensibly value pluralist basis; second, and more deeply, their writings betray significant ambiguity on what value pluralism means in the first place. I identify two central sources of these problems. First, two distinct sets of ideas in Berlin's work, which I label the "moral-practical" and "societal groupings" versions of value pluralism, are persistently conflated by both Berlin and more recent value pluralist theorists. Second, attempts to justify a political view on the basis of value pluralism run aground on a "priority problem" stemming from the central value pluralist concept of incommensurability. In my approach, I maintain the distinction between the moral-practical and societal groupings theories, focusing on the moral-practical version as a more original and less well-understood contribution of Berlin's thought. I also develop a strategy, which I call "giving incommensurability its due," that avoids the priority problem by focusing on metaethical (or second-order), epistemic, and procedural considerations. This strategy supports two major sets of political implications: a liberal-constitutional framework of basic rights and liberties, and a robust, vibrant form of participatory and deliberative democratic politics. This turn to democracy constitutes an important shift vis-à-vis the current literature, which has, up to now, been preoccupied with value pluralism's relationship to liberalism.