Thomas M. Besch

The paper addresses O'Neill's view that her version of Kant's Categorical Imperative, namely, the requirement of followability (RF), marks the supreme principle of reason; it takes issue with her claim that RF commits us to Kantian constructivism in practical philosophy. The paper distinguishes between two readings of RF: on a weak reading, RF ranges over all (practical) reasoning but does not commit to constructivism, and on a strong version RF commits to constructivism but fails to meet its own test, and so is self-defeating. The paper argues that RF, if understood strongly, depends for its reasonableness on reasons that cannot coherently be required to meet RF, so that RF cannot be the supreme principle of reason. The paper considers several responses to this problem in order to suggest that RF depends for its reasonableness on perfectionist considerations.

The dissertation defends that the often-assumed link between constructivism and universalism builds on non-constructivist, perfectionist grounds. To this end, I argue that an exemplary form of universalist constructivism – i.e., O’Neill’s Kantian constructivism – can defend its universalist commitments against an influential particularist form of constructivism – i.e., political liberalism as advanced by Rawls, Macedo, and Larmore – only if it invokes a perfectionist view of the good. (En route, I show why political liberalism is a form of particularism and reconstruct the role of its conception of public justification, its implied contextualism about justified belief, its conceptions of toleration, neutrality, good reasons, and legitimacy, and, not least, its justification-constitutive conception of reasonableness.) Contrary to what is often assumed, then, at the level of a vindication of the very project of a universalist constructivism, universalist constructivists should construe perfectionists not as their opponents, but as partial, though uneasy, allies.