In the cosmopolitan turn in the social sciences, Kant’s legal and political writings are often held up as marking the birth of modern cosmopolitanism. While the idea of cosmopolitanism goes back to the ancient Greeks and Romans and has an early modern life in natural law philosophy, it is Kant who is widely credited with turning cosmopolitanism into a modern moral, legal, and political way of thinking. The welcome republication of Garrett Brown’s Grounding Cosmopolitanism in paperback brings to a wider audience the work of an assiduous and committed scholar of Kant’s cosmopolitanism and its legacy for contemporary political thought.

The stated aim of this book is twofold: It is primarily exegetical, but it also looks to a normative engagement with Kant that goes beyond Kant—one that takes up contemporary cosmopolitan arguments. This twofold aim seems to me entirely laudable, although it is not always clear in practice where the exegesis ends and the normative engagement begins. As a result, the reader is sometimes left wondering whether the author uncritically accepts those parts of the exegesis that he leaves normatively unchallenged.

The main drive of the book is to defend Kant against contemporary criticisms that the author judges unjust or unfounded. Brown writes of “clarifying” various aspects of Kant’s cosmopolitan writings in relation to misconceptions in the current literature. On the whole, I find these “clarifications” well judged. To my mind, they reveal Kant as a classical writer who seeks to harmonize the different elements of the whole, while contemporary cosmopolitan thought tends to split these elements into radical extremes. In contrast, for example, with the emphatic distinctions that exist in the contemporary literature between different types of cosmopolitanism—for example, moral and legal, weak and strong—Brown emphasizes their categorical indistinctness in Kant’s own cosmopolitan writings. A sense of balance is what Brown finds in Kant—be it in his notion of law and morality, rights and constitutionalism, state sovereignty and cosmopolitanism, or culture and universalism.

One of my favorite chapters is that which addresses the relation between state sovereignty and cosmopolitanism in Kant’s work. Brown argues that Kant’s critique of absolute sovereignty, his relativization of sovereignty, is indicative of a refusal to abandon sovereignty altogether in the name of a future cosmopolitan order. Contemporary cosmopolitanism, by contrast, is tempted by the very extremes of sovereignty or cosmopolitan order that Kant managed to mediate. Brown shows very well that Kant saw his own jurisprudence as confronting the problems of traditional natural law: problems such as the interconnection between absolute state sovereignty for some (mainly Western states) and the denial of all sovereignty for others (mainly colonized peoples); the justification of interstate wars between European countries and of colonial conquest outside of Europe; the absence of international laws relating to military aggression and military conduct; the treatment of foreigners arriving on our shores as rightless nonpersons and the absence of any legal obligation to offer them “hospitality”; the lack of any legally binding international authority over nation-states and of any serious philosophical conceptualization of what a Federation or League of Nations might look like. What made Kant’s cosmopolitanism critical was its critique of the then-existing European state order and its speculative reconstruction through the extension of the system of rights beyond the boundaries of the nation-state. While there were, of course, all manner of gaps and incompletions in this critical enterprise, which as Brown argues have to be addressed by subsequent cosmopolitans, what Brown also does is demonstrate the parameters of the project as a whole.

On the more critical side, I wonder if Brown accepts too readily Kant’s own account of his break from natural law theory, and underplays the lines of continuity that connect Kant’s rationalized natural law with traditional forms of natural law. We should not ignore the problem of how far Kant’s own cosmopolitan prescriptions may have replicated the problems he identified. In normative terms, what we largely find in this book is a reformative endorsement of Kant’s cosmopolitan project, which seriously addresses current states of misunderstanding or, worse, wilful denial, and yet I wonder if this is at the expense of an equally serious normative engagement with the conceptual frame and political content of Kant’s project. I am thinking of the kinds of issues that Hegel raised in his critique of Kant: that in overstating his own break from the natural law tradition, Kant also overstated the break between his envisaged cosmopolitan order and the existing system of right; that Kant’s predominantly juridical perspective could not explain how deeply embedded colonialism was in European states; that while republican states may require the consent of the people to go to war, responsibility for making war and peace and for the command of armed forces usually remains with rulers; that in any event the “people” may well be more prone to martial enthusiasm than their rulers; that the “rights of man” can be subverted into a duty of unconditional obedience to the nation that grants these rights and be a source of nationalistic identification with republican institutions; that in times of war, the rights of individuals become a matter of complete indifference compared with the survival of the state; and finally, perhaps, that wars can remain useful even for the most republican of states. Of course, these criticisms themselves need critical scrutiny, and they by no means invalidate the project of “perpetual peace.” However, they indicate not only the massive advance made by Kant in conceptualizing the system of right as a whole in his Metaphysics of Justice but also the possible limitations of his formal natural jurisprudence.

Natural law, Kant wrote, provides “the immutable principles on which all positive legislation must rest.” Kant gave natural law a critical form and function by radicalizing its rational foundations and socializing the idea of right as “the sum of those conditions within which the will of one person can be reconciled with the will of another in accordance with a universal law of freedom.” However, since the main element of his definition of right was negative—the limitation of one person’s freedom in such a way that it may coexist with the freedom of everyone else in accordance with a universal law—law may appear merely as a limitation on freedom and give rise to the demand that this limitation be abolished. At the level of interstate relations, every state can consider international law to be a limitation on its freedom and treat legal indeterminacy as the only true freedom.

While I think that Brown is prone to subsume normative engagement with Kant’s cosmopolitanism to its clarification, the book is extremely careful, helpful, and insightful in its exegetical thoroughness and has an engaging and enlightened spirit running through it. Now that human rights, world courts, international laws, global institutions, United Nations conventions, and an all-inclusive UN are for better or worse part of our world, this book encourages us to look back critically on the contribution of Kant’s prescient cosmopolitanism to the making of this modern world. For example, I wonder whether Brown’s emphasis on Kant’s “adamant” republicanism, if correct, may reinforce an exclusive rather than all-inclusive conception of the Federation of Nations—something more like the League of Nations than the United Nations. However, it should also motivate us to keep alive the critical content of Kant’s cosmopolitanism under changing global conditions.