Michael Allen Gillespie tackles a perennial topic in the history of ideas—the emergence of the “modern” worldview and its relation to the theology of the premodern past—with originality and insight. The sweep of his book is particularly ambitious and impressive. Gillespie manages the difficult task of balancing more than a dozen sharply drawn intellectual portraits of major Western thinkers, while at the same time fitting each of these individual puzzle pieces together into a complex and persuasive metanarrative about the origins of our modern values.

Previous scholarly explorations of this ground, Gillespie notes, have tended to gravitate between characterizing modernity either as a radical break with the Christian past and the rise of a fundamentally new mode of life and inquiry (G. F. W. Hegel, Jacob Burckhardt, Hans Blumenberg), or as a more gradual and continuous transformation that transposed Christian ideas to a secular context (Etienne Gilson, Karl Lowith, Johan Huizinga). However, as Gillespie argues, these approaches have all tended to assume the internal coherence of the theology of ancient and medieval Christendom itself, and to infer that modernity must therefore constitute a response to this theology, either by extending or secularizing it, on the one hand, or by breaking with and thoroughly transfiguring it, on the other.

Instead, Gillespie's book contends that the true origins of modernity are to be found within a tension (or perhaps incoherence) present within orthodox Christianity itself. Christianity's continuation of the radical monotheism of Judaism led it to adopt an ontological realism regarding universals, inspired by its broad universal claims regarding God's omnipotence and omnibenevolence. However, the particularist character of Christianity's account of revelation, especially in its biblical foundations and in the doctrine of the Incarnation, contrarily committed it to a more nominalist and individualist ontological foundation. This conflict recurs again and again within Christianity's history, emerging both in its philosophical troubles (theodicy) and its political conflicts (the Reformation). But Gillespie stresses that modernity as we know it also took shape within the constraints of this enduring metaphysical dilemma, and for this reason, even though the explicit theological reasoning has now largely dropped out of sight, a deep theoretical conflict still remains at its heart. These tensions within Christianity will be familiar to theologians and philosophers of religion, but Gillespie's ingenious contribution is to spot the many ways in which this tension reappears within modern culture itself.

The core of the author's argument can be found in his first chapter: that the origins of modernity can be traced back to the nominalist revolution in medieval philosophy and theology, and that, indeed, the germ of the idea of the modern is already implicit in the controversy to which nominalism gave rise. Ockham, the quintessential nominalist thinker, held that ontological realism about universals, though perhaps initially inspired by claims about God's monotheistic omnipotence, in fact constrained God's omnipotence by making God dependent on forces independent of God's own being and will. In place of this ontological realism, Ockham promoted a radical orientation toward particulars and individualism that led to an increased awareness of contingency and a sharper focus on the will as opposed to reason. It led as well to a more thoroughly voluntaristic understanding of God's intervention in and judgment of the world.

In the centuries immediately following Ockham, Gillespie goes on to argue, the theological conflict exposed by nominalism began to work its way out into the broader culture, first through Renaissance humanism, from Petrarch to Machiavelli and Erasmus, and then through the Reformation thought of Martin Luther and his Protestant successors. Although the humanists rejected the logical squabbles of nominalism as much as those of scholasticism, they nevertheless derived from the nominalists their distinctive concern with particularity and individualism—but at the expense of a full affirmation of God's omnipotence. Luther and the Reformers, in turn, seeking to head off the perceived Pelagianism of humanist individualism, took the nominalist notion in a different direction: a voluntarist reaffirmation of God's omnipotence, bought at the price of undercutting free will and human dignity.

Modernity, on Gillespie's account, arose in response to this set of imperatives and tensions hidden within the nominalist mode of inquiry. By refocusing our attention on questions of becoming and motion, rather than being and universals, nominalism gave rise to an understanding of the relation of God and nature that made possible modern natural science. But its most lasting expressions emerged with Descartes and Hobbes, whom Gillespie pairs as rival fathers of competing versions of modernity: for Descartes, a rationalist modernity, for Hobbes a materialist one. Descartes's rationalism, the foundation of the continental philosophical tradition, solved the enduring conflict by elevating the subjective will of both the nominalist and humanist traditions above the particular limitations of the bodily and finite world. By contrast, Hobbes's materialism, which underwrites much of subsequent Anglo-American philosophy, employed a neonominalism that emphasized the contingency of nature and of humanity's place within nature, but also stressed humanity's potential to shape and constrain this contingency through instrumental reason and convention.

In the book's final chapter and epilogue, Gillespie begins to draw some more explicit connections between the story he has been telling and the enduring contemporary philosophical problems that he claims are rooted in the direction taken by modernity. The insights he begins to develop here are good ones (his brief reflections on the relation of contemporary Islam to these theological problems are particularly provocative), and less historically inclined readers might wish for some further and more explicit unpacking of these connections. But for readers willing to work out certain aspects of the story's connections to contemporary thought on their own, or for readers for whom a genealogy of Western moral and political concepts is an end in itself, Gillespie's impressive book will constitute an important contribution to the macrolevel interpretation of the history of moral and political ideas.