The weight of any argument or theory that is empirically grounded is unparalleled. In contemporary legal discourses, no argument or theory fares better than an empirical one, that is when its foundations can be validated by facts, practices, and existing institutional arrangements – which are, on that occasion, considered self-sustaining. This is what is called empiricism. International lawyers have long understood the argumentative convenience of empiricism, which has accordingly been thriving in contemporary international legal thought. Only international lawyers amenable to the natural law tradition have continued to prefer to ground legal argumentation in normative and theoretical postulates and have played down the foundational role of facts, practices, and existing institutional arrangements which, in their view, cannot be self-sustaining. It is accordingly no surprise that the resilient debates between mainstream empiricists and moralists have been revolving around the validating role of these facts, practices and institutional arrangements.
This dichotomous image of the structure of international legal argumentation is challenged by The Thin Justice of International Law (hereafter TJIL) written by Professor Steven Ratner. Indeed, in this book, he offers us an elegant refinement of the natural law tradition in international law by seeking to bridge the abovementioned divide between empiricists and moralists in international legal thought. It will however be argued in the following paragraphs that the most innovative aspect of TJIL does not lie with the stylish blend of empiricism and morality it relies on but rather with the epistemic union between international lawyers and moral philosophers which it calls for.
The rich and wide-ranging discussion provided by TJIL can be summarized as making the three following moves. First, it posits a minimalistic two-tier notion of justice built on peace and human rights. This minimalistic notion of justice is called “thin justice” because it is meant to echo the current practices and rules of international law. Second, it evaluates existing rules and institutions in eight areas of international law with a view to determining whether applicable rules conform to this notion of thin justice. The result of these two steps is a road map for compliance and reform. When rules and institutions are found congruent with thin justice, international actors are provided with an incentive to comply with them. When rules and institutions are found at odds with thin justice, reform must be carried out. As the nuanced discussion in TJIL makes clear, this road map for compliance and reform, when applied across the eights fields under scrutiny, does not operate in a Manichean way. Congruence with the standard of thin justice is complex. TJIL reaches the conclusion that most core norms of international law meet the standard of thin justice, some very important ones do not and other norms are simply not amenable to any such judgment. Taken together, these three moves constitute an impressive cartographic exercise about what ought to be complied with and what ought to be reformed – simultaneously demonstrating the remarkable mastery by the author of TJIL of most areas of international law.
It goes without saying that if there were only these three steps (i.e. deductive, evaluative, prescriptive) TJIL would be anything but revolutionary. Indeed, such a three-step discussion corresponds, roughly speaking, to a common natural law approach whereby rules are evaluated on the basis of a posited normative framework with a view to generating an agenda for reform and/or compliance. Yet, Ratner’s innovation is in that TJIL’s posited normative framework (based on peace and human rights) is grounded in actual practice and “takes account of core realities of international politics and the global system” (p. 4). For him, “[e]ach discipline must eventually put its faith in real-world decision makers – states, international organizations, NGOs, corporations, citizens, and others – to carry out its particular visions” (p. 1).
In other words, TJIL provides an empirically grounded theory of justice which it is subsequently used to evaluate existing rules and institutions. Such a methodological blending of the ‘deductive’ and the ‘inductive’ is what I would call a “mushroom” approach: a certain standard or framework is inferred from one’s observation of the reality before elevating it into a universal evaluative framework on the basis of which the practice – in which it originates – is re-assessed. It is true that such a “mushroom” methodological construction is not unprecedented. For instance, it is found in the sophisticated inquiries designed by those dubbed the “managerialists” (see here), who have sought to domesticate all exercises of public authority and subject them to criteria of accountability, transparency and participation (see here). What is new, however, is the deployment of such a “mushroom” approach in natural law scholarship.
It does not take much familiarity with debates on methodology to realize the considerable methodological advantage that such a “mushroom” approach confers on legal argumentation. Indeed, it allows one to circumvent traditional objections against the postulated nature of natural law evaluative frameworks as international law can seemingly be appraised from an internal perspective, that is on the basis of a notion of justice that is international law’s own. Said differently, such a self-generated evaluative standard can no longer be dismissed for being arbitrary, hegemonic, or metaphysical – as the traditional charges against natural law go – for it is meant to be autonomous and extracted from international law itself.
The empirical sophistication offered by TJIL is obviously informed by its author’s awareness of the methodological criticisms commonly raised against natural law approaches to international law and their postulated evaluative frameworks. Indeed, Ratner shows that he is well aware of the problems inherent in postulated evaluative methods. It is also his methodological awareness that brings him to usefully make clear that TJIL does not seek to provide either a theory of validity or a theory of compliance, let alone a grand moral theory which would inextricably be condemned as a fantasy for disregarding law at work.
Whether TJIL actually succeeds in avoiding the traditional pitfalls of postulated evaluative frameworks is not a question that ought to be addressed here. It seems more relevant to highlight that TJIL, while putting forward an empirically generated notion of justice, simultaneously refuses to embrace mainstream empiricism. Indeed, TJIL still seeks to make a moral argument about international law. In this respect, it is noteworthy that after taking pains to distinguish his empirically grounded non-ideal theory of justice from naïve morality, Ratner is prompt to highlight that his practice-grounded notion of thin justice does not amount to a vindication of the status quo in international law or a betrayal of the advancement of the global justice project. If in a certain paragraph he claims that practice and rules of international law inform a thin concept of justice, he defends, in the ensuing paragraph the recurring need of reforming international law to vindicate global justice. In his view, global thin justice is thus both constituted by and constitutive of international law. This is why TJIL reads as an attempt to preempt the charge of utopia commonly associated with natural law by extracting justice from the world as it sees it, while trying to rebut the charge of apology of current rules and institutions commonly associated with mainstream empiricism. The image resulting from such argumentative oscillations is that of a remarkably knowledgeable author nimbly walking a tight rope, seeking to elude both the utopian quest for ideal justice and the apologetic defense of current rules and institutions.
It is noteworthy that this equilibrist’s performance is discontinued in the last part of the book where the author sheds the empirical constraints that had justified the adoption of a thin concept of justice and discloses its heartfelt vindication of an unbridled (“thick”) notion justice. In fact, the empirically constrained notion of thin justice is then tossed out in favor of a thick notion of justice where the careful balance between human rights and peace is now clearly titled towards the former. In this final part, TJIL reads as if, after 416 pages of self-restraint, its author had decided to emancipate himself from the constraints of “reality” in order to give free rein to an unconstrained theory of global justice. This move away from empiricism allows him to develop an even more ambitious programme for reform.
Steven Ratner’s escape from his self-imposed empirical cage in the last part of the book warrants a final observation, since it confirms the multidimensional epistemological agenda of TJIL. It is not only that such a breakout allows its author to redeem himself in the eyes of natural lawyers who may have been offended by his flirting with an empirically generated notion of justice in the rest of the book. More fundamentally, this last part consistently confirms that TJIL is a work aimed at rehabilitating international law as a platform to theorize global justice by international lawyers and moral philosophers working together. In that sense, TJIL can be read as a call for moral interdisciplinarity which entails that international lawyers and moral philosophers unite in a new epistemic community where the efficacy of thin justice is put at the service of the lofty ambitions of thick justice. More than the blended empiricism on which it relies, this plea for an epistemic union between international lawyers and moral philosophers is nothing less than a reinvention of the natural law tradition in international law.