The idea that public reason provides the basis for justifying normative claims, including fundamental ethical and political claims, has acquired new resonance in recent decades. Yet it is not obvious whether or how the fact that a process of reasoning is public can contribute to fundamental justification. Indeed, since conceptions of reason, of the public, and of the boundaries between public and private are various and strongly contested, any claim that public reason justifies is multiply ambiguous. Moreover, some popular conceptions of public reason are quite ill-suited to any justification of fundamental norms. I offer three contemporary examples.

First, reasoning might be thought of as public simply because it is actually done in public or by the public, for example, in a context of political debate or of discussion in the media. Publicity in this sense may be crucial for any proposal to have democratic legitimation, variously conceived; but it cannot supply fundamental justifications. Democracies presuppose bounded territories and distinctions between citizens and noncitizens and, more broadly, between members and nonmembers (aliens, resident, and other); democratic process presupposes at least a rudimentary range of institutions such as the rule of law and at least minimal personal and civil rights.