Making a connection between ‘post-modernism’ and post-truth has by now become a standard trope, both within academia and popular discourse, despite post-truth’s only recent emergence as a concept. Such claims are often rather vague and fanciful and lack an altogether credible account of either phenomenon in many cases. This Chapter argues however that within a legal context, there is the emergence of a legal post-truth which is the direct consequence of a concrete form of post-modernity within legal practice and thought. (...) While law may be called upon to engage in judgments of ‘truth’ in numerous interesting ways, it does not itself have any particular form of privileged access to the truth of statements or allegations, even though it is often treated as doing so. However, the most persistent question which law must deal with, and indeed the most persistent question within legal philosophy, relates to a deeper form of inquiry into truth: the question of legal truth. In simple terms this refers to the correctness of any particular proposition of law. Within legal theory, this expands to the larger question of what makes, in general, any legal proposition valid, or true. Reflecting upon legal scholarship through the lens of truth reveals that theories of law can be broken down into two broad and radically distinct categories. On the one hand, there exist empirical accounts of law which fundamentally understand questions of legal truth as social questions whose answers are empirically demonstrable. On the other hand, there are ‘idealist’ accounts of law which view legal content, and hence truth, as existing in some way or other in a manner which transcends social practice and which is autonomous from it. Both of these classical accounts, while radically different, share an interesting paradox: they see truth in law as an objective fact, but one which is fleeting and distant, far from the paradigm of legal certainty upon which the ideology of law is partly based. However, such accounts of legal truth share many other unstated aspects, and are largely based upon ideas which place the separateness and completeness of legal systems at their heart, providing either a unified ideal or a unified empirically observable social practice. However, they are share a common flaw, namely the failure to account for what might be called a post-modern phase of development in law, in which ordinary legal questions now regularly require the complex and non-hierarchical interaction of competing legal systems with different ‘truths’ and different ways of arriving at such truths. Such phenomena are commonly referred to as legal or, at times, constitutional ‘pluralism’. This post-modern turn within law has also produced therefore what we might call a form of post-truth within law. This is particularly significant because it places under great strain both the empirical and ideal accounts of legal truth and require us to re-elaborate an account of what makes a legal proposition true. From certain perspectives, this legal post-truth shares certain important aspects with the cultural phenomenon of post-truth, namely its apparently capricious and deracinated nature. However, it is argued in this Chapter that, in the legal context at least, post-truth allows for the transcendence of the empirical/ideal divide and the revealing of deeper forms of legal truth and our ability to account for them through theory or, put more simply, explanation. Upon greater reflection, legal truth is generated by the very forms of argument, or modes, which allow access to it. Such forms of argument exist also to produce legal truths outside and between legal orders where these appear to conflict or collide. While some legal scholars and others claim that such pressures on structures of knowledge reveal the end of the potential for law to generate truth, it is argued here that, on the contrary, they require a more open and more transparent use of the pure methods and modes of reason which both reveal but also generate legal truth in the first place. This is relevant to post-truth more generally in one specific way, despite the numerous idiosyncrasies of legal truth and knowledge: when assertions of truth within structures of power seem to come to embody the perspectivism and relativism used as methods of deconstruction, the post-modern and deconstructionist projects themselves require radical change: they stay true to their goal of deconstructing structures and discourses of power by applying the classical epistemologies which are rejected by those in power. Just as legal outcomes which are asserted rather than reasoned or justified are most convincingly deconstructed through sober legal modes, so can the post-modernist project find purpose in a world where dominant epistemes seem to have come to embody a simplistic version of post-modernist critiques. (shrink)