Anthony Pagden is one of the leading historians of political ideas of the Spanish Empire, made famous by his classic The Fall of Natural Man: The American Indian and the Origins of Comparative Ethnology (Cambridge University Press, 1982). He has since gone on to write about warfare, empires, and world history. This new book returns him to older themes and places his reflections on Spanish imperial thinkers into a wider frame of European deliberations about the role of empires in creating humanitarian thinking and their legacies for modern-day human rights.

First a clarification about what this book is not about; the title is misleading. The bulk of the book is concerned with Western European, especially Spanish and British, thinking about empire in the early modern period. It is neither global (there is no China, Mughal, Russian, or Ottoman discussion, for instance, nor does the vast literature on the American empire make an appearance, except to the extent that colonial debates before 1776 figure as part of a wider British spectrum), nor does it really deal with the post-1800 years. There is a final reflection on human rights in our day, but it is a leap from Pagden's suggestive reflections on Immanuel Kant. There is no discussion of liberalism and empire, nor a treatment of anticolonial thinking, which have been the subjects of a great deal of discussion in political theory in recent years.

Second, it is focused on ideas about empire. This book is not an institutional or political-economic story. The treatment of ideas is a conventional one, premised on the reading of foundational texts, not a meditation on their circulation, reception, influences, or their contexts.

But the book is original and unconventional in the way it charts out the legacies of the Spanish conquest—though Pagden brilliantly explores the ways in which the very meaning of “conquest” itself was invented and debated—encounters with Native Americans, and the heritage of thinking about the rights of others, especially the racialized subjects of conquering Europeans, in the humanistic traditions. This is why Pagden starts with Francisco de Vitoria and the intellectually fertile Salamanca School to lay out the “burdens” that Europe's first empires created for themselves. These founders of international law had the predicaments of the Spanish Empire, and especially the morality of conquest and colonization of the Americas, on their minds as they pondered the possibilities of a universal monarchy. Vitoria was not the first to pose the question, what “right” do Europeans or Christians have to impose their will on others? But he was perhaps the most eloquent and pursued the early modern logic to its limits, entangling natural rights and the law of nations to envision a human community. Ever since, early modern thinkers like Grotius and Gentili have reflected on just war and an ancient right of all peoples to enjoy access to other peoples and global resources, often drawn from an image of Rome as the maker of a global civil society.

But it was not all so easy. What vexed early modern thinkers was that not all people were equal, especially the Native American. Humanity was divided, not one. Talk of civilizations and increasingly of races gave reasons to control, oppress, and deny the rights enjoyed by some at the expense of others. At its extreme was the notion of terra nullius, explored brilliantly in chapter 4 of this book, which justified occupation by reimagining other lands as basically empty, to be converted into plantations. In the middle of Pagden's book, a comparative history of imperial thinking materializes, one Spanish, resting on Catholic conquering precepts, and another English, emerging as a Protestant, colonizing project. And so a burden was sown into the very fabric of European imperial ideology, one that yearned for universality yet inscribed a hierarchy of the world's peoples—and thus the legitimate claims on the part of some states to dominate others. This is why early modern international law was fundamentally imperial; it was also therefore incapable of being truly international.

This is the core thesis of Pagden's book, and why his story culminates with Kant's observation that there was a world-historical shift from natural rights and the law of nations to a new regime governed by “cosmopolitan right” and international law. Kant did not come up with this notion out of whole cloth. There had been, since the eighteenth century, more and more debate about the need to replace ancient traditions of conquest with modern possibilities of commerce. Trade and the prospects of global interdependence could soften—“sweeten,” in Montesquieu's formulation—a world of rivalrous and predatory empires. They could lay the foundations for a different, more peaceable, global order, one which finally transcended the vexations of the Salamanca intellectuals who tried to give moral justification to dominion, but ultimately failed to do so in a way that was truly universal.

While it was empire that pulled the world together and created the interdependencies that philosophes and political economists extolled, it took a repudiation of empire to create the modern framework for humanitarianism and human rights. For Pagden, those who decry modern human-rights talk as just another “Western” imperial project do not understand this fundamental transition in Western political thought. Nor do they understand the paradoxical legacies of European empires, which sired structures and ideas in the sixteenth century that later thinkers had to repudiate in order to invent a new legal framework for world affairs.

Ultimately, Pagden's is the story of European mythographers of empire—those, like Vitoria, who struggled to give empire moral ballast, as well as those, like Kant, who would deny that any true world legal order could accommodate empire. In exploring the continuities and discontinuities of imperial political imaginaries, this book has no peer. It is loaded with fascinating insights and surprising turns. But it is also constrained by the ways in which it bounds its subject. The absence of a wider spectrum of voices engaged in the global debates about empire means that Pagden's critique of those who complain about Eurocentric models of human rights is not nearly as insightful as his genealogy of Eurocentrism.