If by the early years of the 20th century traditional monotheism had not died in the hearts and minds of European intellectuals, as Friedrich Nietzsche had suggested in the mid-1880s that it would, among them God was nonetheless on life support. But the result, even for many Nietzscheans, was less atheism than a blossoming of heretical God-talk, some of it reviving and reconstructing older heresies.

In the critical period between the world wars, as Benjamin Lazier shows, two opposing heresies stood out among Christian and Jewish intellectuals alike: Gnosticism and pantheism. Proponents and opponents used both these terms with maddening imprecision, but Lazier makes a strong case that they were pertinent nonetheless.

Gnosticism was manifest, above all, in the postwar–World War I crisis theology of Protestant theologians such as Karl Barth, Friedrich Gogarten and Eduard Thurneysen. Although hardly replicating the ancient heresy in every particular, the crisis theologians, responding to the ghastly carnage of the Great War and to what they regarded as an insipid liberal theology wedded to progressive hopes that the war had shattered, revived a gnostically inflected conception of a “wholly other,” transcendent God. Theirs was a deus absconditus, who stood distant and apart from a sinful, abandoned world. This God could be heard only by means of revelation from a beyond to which humans had no other access.

As Lazier says, it’s “difficult to overstate the importance” of Barth’s Epistle to the Romans in the interwar period. That work did the most to “systematize a gnostic language of heresy spoken well beyond confessional boundaries, and it set the terms—whether embraced or disputed—for much of the Christian and Jewish thought in the wake of Versailles.”

Recoiling from Barth’s dark vision, other postwar theologians were drawn to the polar-opposite heresy, pantheism. Pantheism’s God was not wholly other but wholly immanent, one with nature. This pantheistic impulse was manifest most prominently in a remarkable interconfessional explosion of renewed interest in the work of the great 17th-century philosopher and Jewish heretic Baruch Spinoza, the scourge of monotheists in his own time and since.

Lazier, who teaches at Reed College in Portland, Oregon, is less interested in the proponents of Gnostic and Spinozist heresies themselves than in the wider “efflorescence” of the debates they occasioned. He means to demonstrate that historians would be remiss if they fail to “take theology seriously as a cultural and intellectual practice” in 20th-century intellectual life, a practice that resonates well beyond the work of theologians.

In particular, in God Interrupted Lazier seeks to demonstrate that interwar theological disputes served as the seedbed for the thinking of three major but disparate German-Jewish thinkers (and friends): philosopher Hans Jonas, political theorist Leo Strauss and historian Gershom Scholem. The most renowned work of all three emerged in the years following World War II, and little of it bore obvious marks of a common origin in the theological disputes of the 1920s and early ’30s.

In this “unconcealment,” to use an appropriately Heideggerian term, Lazier performs brilliantly. Although all three of his subjects were deeply moved by Gnostic arguments (those of the early Barth in particular) and contemptuous of wholesale pantheism, each might be said to have argued that an absconding God had left enough of himself behind in creating the world to constrain and guide human self-assertion (though this is not exactly the way Lazier himself puts it).

Both Jonas and Strauss built upon a shared conception of a teleological nature, one that recovered the Greek notion of physis from its banishment by modern, mechanical science. Jonas, whose work is less known in the United States than it should be (he spent many years here after World War II), made his initial mark in the early 1930s as a critical analyst of ancient Gnosticism, but then went on to develop a remarkably original philosophical biology and environmentalism that recast Kant’s categorical imperative to read: “Act so that the effects of your actions are compatible with the permanence of genuine human life.” In particular, Jonas emphasized the obligations of human beings as the “shepherds of Being-in-general,” to use another term of his teacher Heidegger. The German edition of Jonas’s The Imperative of Responsibility sold hundreds of thousands of copies, and he became the philosophical voice of the Green Party.

Jonas coupled this ethics with a speculative, post-Auschwitz theology that posited God as “a needful being who had created the world but spent himself entirely in so doing. This was a god relegated to the back seats of the cosmic theatre he had built but could not direct, for all his vital interest in the drama’s outcome an impotent spectator nonetheless.”

Strauss derived from physis a conception of natural right with which to hem in a Hobbesian/Nietzschean politics guided by nothing more than historically contingent human conventions. An apparent atheist, Strauss nonetheless made full use of Gnostic theology to authorize an incommensurability between reason and revelation and to vest authority in human politics in a secular philosophy capable of discerning moral imperatives prior to mere nomos, or human law. (Strauss was, as Lazier nicely puts it, an “ante-nomian”.)

Scholem as a young man was drawn deeply to a transgressive, Nietzschean, anarchist ethics, one that the more radical Gnostics claimed was authorized by God’s absence (a position that Scholem described in an important early essay as “redemption through sin”). He even flirted with the composition of a “Jud enzarathustra.”

But over the course of his career, by means of his revolutionary investigations into the history of Jewish mysticism and of the Kabbalah and the competing languages of Gnosticism and pantheism that suffused it, Scholem, like Jonas and Strauss, hammered out a dialectical third road that sustained the human autonomy that pantheism annihilated but subjected it to a divine remnant in creation that Gnosticism denied. Here too a Heideg gerian move brought Nietzsche to heel. God, in absconding from the world, Scholem argued, had left behind a “nothingness” essential to Being, including Dasein (human being): a “trace of divine transcendence, however nebulous and faint,” that served to circumscribe human self-creation.

A Zionist from a young age, Scholem was interested above all in Jewish autonomy and self-assertion. He was drawn to the wildest antinomian heretics among the Jewish mystics, even 18th-century nihilist Jacob Frank, who preached a doctrine of “purification through transgression” and called for the “transvaluation of all values of the Jewish tradition” (the “Jewish [Charles] Manson,” Lazier labels him). Yet he brought his own Zara thustrian ambitions to heel and eventually crafted a Zionism at once resolute and averse to messianic ambition.

God Interrupted is intellectual history of a high order: eye-opening, skillfully wrought, rich in implication and touched with literary flair. Lazier refrains from fully judging his protagonists, though his sympathies for Jonas and Scholem and his skepticism toward Strauss are clear. Nonetheless, in writing of a pivotal moment in modern theology’s history and its reverberations, he has not only made his case for its wide historical significance but also crafted a book that will provoke those still struggling to determine the amplitude and frequency of God’s oft-interrupted call.