SIMON CRITCHLEY, A BRITISH PHILOSOPHER based at The New School in New York, is best known for books like Very Little... Almost Nothing (1997), Infinitely Demanding (2007) and The Book of Dead Philosophers (2009), a bestseller that has helped to cement his status as a prominent public intellectual. (Recently this status was further solidified by a noteworthy spat between Critchley and the Slovenian philosophical superstar Slavoj Žižek, about which more below.) Over the years he's developed a reputation as a rigorous philosopher in the "continental" tradition, playing a major role in the Anglophone reception of tricky French thinkers like Emmanuel Levinas and Jacques Derrida. Yet he's also proved to be passionate about making philosophy an accessible part of contemporary culture — for instance, through "The Stone," an opinion series he organizes for the New York Times.

Throughout his career, Critchley has recast philosophy as a response to two types of "disappointment": the religious (how are we to deal with life after the death of God?) and the political (what's left for the Left to rally around, in light of the apparent triumph of neoliberalism?) His latest book, The Faith of the Faithless, systematically connects these two threads. We live, Critchley claims, in an age defined by a "dangerous interdependence of politics and religion," where warfare is underwritten by overt religious rhetoric. "Somehow we seem to have passed," he observes,

from a secular age, which we were ceaselessly told was post-metaphysical, to a new situation in which political action seems to flow directly from metaphysical conflict ... in which religiously justified violence is the means to a political end. 

But if today's violent conflicts — in the Middle East, for instance — are connected to a "clash of fundamentalisms," this, for Critchley, is only a symptom of something more deep-rooted. Indeed, our religious and political disappointments could turn out to be inextricable, for Critchley contends that politics per se is religious; and The Faith of the Faithless makes a compelling case for this claim.

Critchley begins the book by unpicking a typically knotty epigram from Oscar Wilde: "Everything to be true must become a religion." The author's first philosophical feat is to show us why we should take this bon mot seriously. If we're to appreciate religion's political power, we must understand how belief imbues ideas with truth, how faith lends weight to an argument. For Critchley, Wilde's riddle has something to tell us about why beliefs, even the secular sort, are so often wrapped up in a "framework of ritual." Even our most rational beliefs are brought about partly through faith; they're religious in structure. So, secular creeds must mimic religious ones if they're to be taken as true. 

Putting Wilde's words to work on world politics, Critchley turns to the tradition known as "political theology," a subject best summed up by Carl Schmitt in his book of the same name. In that work, Schmitt declares that "all significant concepts in the modern theory of the state are secularized theological concepts." For Critchley, these words resonate with Wilde's aphorism, shedding light on how "political forms" — from fascism to liberalism — are fashioned out of the raw mate...