Peter Sloterdijk has been one of Germany’s best-known philosophers for 30 years, ever since the publication of his Critique of Cynical Reason in 1983—a thousand-page treatise that became a best-seller. Since then Sloterdijk has been at the forefront of European intellectual life, contributing to public debates over genetic engineering and economics and hosting a long-running discussion program on television, all while publishing a steady stream of ambitious philosophical works. The Critique of Cynical Reason appeared in English many years ago, but it is only recently that Sloterdijk has begun to emerge on the American horizon. Bubbles, the first volume in a trilogy called Spheres, his magnum opus, appeared here in 2011. Now it is followed by You Must Change Your Life, another wide-ranging and challenging book. Along with Rage and Time, which appeared in English in 2010, these volumes make it possible to begin to come to grips with Sloterdijk as a stirring and eclectic thinker, who addresses himself boldly to the most important problems of our age. Above all, he is concerned with metaphysics—or, rather, with what to do with the empty space that is left over when metaphysics disappears—along with religion, faith in revolution, and the other grand sources of meaning that long gave shape and direction to human lives.

Sloterdijk was born in 1947, making him just the right age to participate in the student movement of the 1960s. By the early 1980s, when he wrote Critique of Cynical Reason, the idealism and the world-changing energy of that movement had long since dwindled into splinter-group violence, on the one hand, and accommodation to the realities of capitalism and the Cold War, on the other. In that cultural moment, Sloterdijk’s diagnosis of “cynicism” was very timely. “The dissolution of the student movement,” he wrote, “must interest us because it represents a complex metamorphosis of hope into realism, of revolt into a clever melancholy.”

Despite its parodic Kantian title, Sloterdijk’s Critique is not a work of theoretical abstraction; it is a highly personal confession of this generational world-weariness. As a philosopher, Sloterdijk is especially struck by the way he and his peers were able to master the most emancipatory and radical philosophical language, but utterly unable to apply its insights to their own lives and their own political situations. Coming after Critical Theory, whose post-Marxist diagnoses of social ills are a key reference point and antagonist for Sloterdijk, younger thinkers have found themselves brilliant at diagnosis and helpless at cure. “Because everything has become problematic, everything is also somehow a matter of indifference,” Sloterdijk observes. The result is cynicism, which he defines in a splendid paradox as “enlightened false consciousness”: “It has learned its lessons in enlightenment, but it has not, and probably was not able to, put them into practice.”

If we are to break out of this learned helplessness, Sloterdijk argues, we must ransack the Western tradition for new philosophical resources. Such ransacking is exactly the method of Sloterdijk’s thought, first in the Critique and then, on an even grander scale, in Bubbles and You Must Change Your Life. Drawing on very wide reading—wider, the reader often feels, than it is deep—Sloterdijk excavates the prehistory of contemporary problems, and some of their possible solutions. In the Critique, he offers an extended analysis of the culture of Weimar Germany, in which he locates the origin of twentieth-century cynicism—as well as describing the many sub-varieties of cynicism (military, sexual, religious), and doing a close reading of Dostoevsky, and cataloguing the meaning of different facial expressions. The effect on the reader is of being shown around a Wunderkammer, where what matters is not the advancing of an argument but the display of various intellectual treasures.

If the "cynicism" that Sloterdijk describes is a post-'60s phenomenon, the prescription that he offers is a return to '60s values.

If the “cynicism” that Sloterdijk describes is a post-’60s phenomenon, the prescription that he offers is a return to ’60s values of spontaneity, passivity, and the wisdom of the body. But he does not describe these in the language of hippiedom; instead, and characteristically, he finds a grounding for them in the oldest regions of the Western philosophical tradition. The hero of his book is Diogenes, who was himself derided as cynical—literally, “dog-like”—by the people of Athens. But there is a vast difference, Sloterdijk argues, between the exhausted cynicism of the late twentieth century and what he calls, using Greek spelling, the “kynicism” of Diogenes. When Diogenes defecated or masturbated in the street, when he slept in a bathtub, or told Alexander the Great to get out of his sunlight, he was employing a joyful language of radical bodily gestures to defeat the philosophers’ imprisoning language of abstract concepts. “Neither Socrates nor Plato,” Sloterdijk writes, “can deal with Diogenes—for he talks with them ... in a dialogue of flesh and blood.”