Truth is an important topic here, not because Rawls developed a theory of truth as it applies to morality or political justice but because he studiously avoided doing so. From his earliest articles through the publication of A Theory of Justice in 1971, he developed a conception of moral and political justification that involved no starring role for the concept of truth. In his mature political liberalism, he took a step beyond that, and insisted that political liberalism should not avail itself of the concept of truth. Only in between, at the brief high-water mark of his Kantian constructivism (with the publication of “Kantian Constructivism in Moral Theory” in 1980) was Rawls tempted into offering the rudiments of an account of moral and political truth. With his turn to a “political, not metaphysical” approach less than a decade later, however, Rawls left off any development of these hints and instead took up the more self-denying stance just mentioned.

Rawls 's principal motivation for avoiding any talk about truth in his later theory arose from his view that it is a deeply controversial matter what the nature of truth is, whether specifically in morality or more broadly. To understand his thinking on this topic, then, one needs to have some sense of what the controversies are.