I’ve recently had the privilege of taking over the Stanford Encyclopedia of Philosophy entry on Public Justification from political philosopher Fred D’Agostino. Our new co-authored entry (which I will fully take over in 2016) should be of interest to those readers interested in political philosophy generally and public reason views specifically. It is cool to define a concept for public consumption, so please, enjoy. I suspect even seasoned political philosophers will learn something (especially from our attempt to distinguish the idea of public reason from the idea of public justification). The opening paragraphs:

Some political philosophers and theorists place a requirement of public justification on the permissible use of state coercion or political power. According to these theorists the recognition of citizens as free and equal moral persons deserving of respect requires that coercion be justified for or to others by their own lights, or with reasons that they could recognize as valid. On this view, a public justification is achieved when members of the relevant public have adequate or sufficient reason to endorse a particular coercive proposal, law or policy. Those who endorse this requirement are often called public reason liberals as they hold that the coercive power of the state must be justified for or to all members of the public on the basis of good reasons.

Coercion is taken to be the object of public justification because it is the characteristic feature of political life. Charles Larmore remarks that public justification has “to do with the sort of respect we owe one another in the political realm — that is, in relationships where the possibility of coercion is involved” (Larmore 2008, 86). Rawls’s principle of public justification holds that it is political power that must be justified (Rawls 2005, 12) since, as he remarks, “political power is always coercive power” (Rawls 2005, 68). Jonathan Quong holds that public justification concerns the imposition of coercive laws (Quong 2011, 233–250). The scope and individuation of coercion is addressed in the next subsection, but here it must be emphasized that, as Christopher Eberle puts it, (2002, 54) “the clarion call of justificatory liberalism is the public justification of coercion.”

Notwithstanding the characteristic association between public reason liberalism and the requirement of public justification, public justification is the genus and public reason the species. The idea of public justification is, at its root, an idea about what justifies coercion. Although we can arrive at a state in which some social arrangement is publicly justified by an explicit course of reasoning leading to the legitimation of that state, this is not intrinsic to the more general idea of public justification, as we will see later. In particular, we can arrive at a state in which some arrangement is publicly justified by non-deliberative, indeed non-discursive means, and it is for this reason that public reason is a narrower notion than public justification.

John Rawls was the foremost advocate of the idea of public justification, though its importance is also stressed in the works of Jürgen Habermas, David Gauthier, Gerald Gaus, Stephen Macedo, Charles Larmore, Seyla Benhabib and many others. There is considerable disagreement about how to understand the idea. For instance, some hold that all public justifications must occur via shared or accessible reasons (often called consensus theorists), whereas others (often called convergence theorists) hold that public justification can be obtained if different points of view each provide good grounds for a particular policy (see Section 2.3 below). Public justification theorists also disagree about the right level of idealization or how to attribute reasons to citizens, which often involves imagining them as possessing superior information and cognitive abilities. This article explicates the idea of public justification in terms of a Public Justification Principle (PJP) that provides a classificatory system for these competing conceptions.