The Pluralist–Solidarist Debate in the English School

In his 1966 essay, “The Grotian Conception of International Society,” Hedley Bull distinguishes between two conceptions of international society: pluralism and solidarism. The central assumption of solidarism is “the solidarity, or potential solidarity, of the states comprising international society, with respect to the enforcement of the law.” In contrast, pluralism claims that “states do not exhibit solidarity of this kind, but are capable of agreeing only for certain minimum purposes which fall short of that of the enforcement of the law.” Bull’s formulation of pluralism and solidarism, and the way he set the two concepts against one another, exerted a profound influence on subsequent English School scholarship and sparked the pluralist–solidarist debate. This debate revolves around theorizing different kinds of order, in particular international and world order. The English School used the language of “pluralism” and “solidarism” to address the legitimacy of humanitarian intervention. After the issue of humanitarian intervention was pushed down the list of scholarly priorities, pluralism and solidarism sparked renewed interest from scholars such as Barry Buzan, Andrew Linklater and Hidemi Suganami, William Bain, and Andrew Hurrell. Despite the debates triggered by the pluralist–solidarist debate, the vocabulary of pluralism and solidarism is a promising means of tackling questions and issues that are undertheorized or largely neglected in English School theory, including those relating to the place of sub- and supranational entities in international society, the meaning and scope of world order, and the significance of international political economy in theorizing different kinds of order.