To be posthumously considered a Jewish philosopher may not have been desirable for Hans Jonas (1903–93), a student of Martin Heidegger and the Protestant theologian Rudolph Bultmann. His first major published work, Gnosis und Spätantike (1934), appearing in English as The Gnostic Religion (1958), however, clearly places him in line with the scholarship and thinking of a host of German Jewish intellectuals in the last years of the Weimar Republic. His early work is akin in some respects to that of Gershom Scholem, with whom he shared a lasting friendship. With Martin Buber and even Ernst Bloch, whom he would later oppose, he shares a theological impulse that informs his historical research. Yet Jonas was neither a historian nor a theologian. In his later years, his attention turned to practical philosophy, and he was concerned in particular with a philosophy of nature. A philosophy without preconditions would be his aim. In contrast to theological speculation, Jonas would later prize thinking that was grounded in intellectual neutrality. He sought to develop an ethics that could not be denied its universal meaning on account of its author being a Jew. “Thinking,” he once remarked, “the true occupation of the philosopher, must be entirely free of such binds and hereditary preconditions in orientation.” Even faith in the existence of God tainted its absolute autonomy: “[T]he method of philosophy demands a clear commitment to atheism,” he stated. And yet, “as both philosopher and Jew, there is an obvious tension.”

Jonas's biography follows the trajectory of others in his generation. His study of Gnosticism appeared in print one year after his flight to England (1933) and, in retrospect, can be read as one more signpost at the end of the Jewish Enlightenment, which reached its pinnacle in the German-speaking world. Britain served as a medium and a transit point for Jonas twice: once en route to Palestine and again when he was a victorious soldier returning to Germany. He undertook the voyage to Jerusalem with a great spiritual longing that was shared with other German Jews of his time, his Zionism bearing strong religious hues. Upon his arrival in Jerusalem, he joined up with Gershom Scholem and the Pilagesh circle, laying the groundwork for an academic career. His intellectual pursuits were mitigated by the outbreak of war, and he joined the Jewish Brigade as part of the British forces. At the end of the war, he proceeded to Canada and then on to New York, where in the 1950s he was appointed professor of philosophy at the New School for Social Research.

The Jewish dimensions of The Life and Thought of Hans Jonas bring Jonas's bifurcated role as “philosopher and Jew” into focus. The intellectual harmony of these two worlds is the key question. Are there two Hans Jonases, and if so, which is the Doppelgänger? Christian Wiese renders a large cache of unpublished material accessible and offers the English reader a wide variety of untranslated letters, lectures, and interviews. This is an addition to the tremendous effort that he has undertaken to make Jonas's work available in German. Most notable is the annotation of extensive interviews with Jonas published in 2003 under the title Erinnerungen, which has now also appeared in English with Brandeis University Press. Yet the Jewish dimensions of what was clearly a central figure in modern Jewish thought still remain rather ambiguous. It is not clear whether we should understand Jonas's Judaism as a necessary precondition or as a hindrance that would mitigate the neutrality of his philosophy (as an absolute absence of preconditions would seem rather implausible).

This problem becomes apparent in Chapter 3, which begins with Jonas's opposition to Heidegger and Bloch and concludes with a discussion of his address on “The Concept of God after Auschwitz: A Jewish Voice.” Jonas's belief in the existence of God is a recurring question throughout the book. It is here that we come to understand his belief as qualified. Jonas is resolved to uphold the absolute benevolence and omniscience of God, while jettisoning omnipotence. In his defense, he may have reserved enough to constitute the basis of reasonable belief. But whether God's all-goodness can be preserved with a corresponding notion of divine incapacity is a question that requires further investigation.

An identifiable Judaic motif here is the ẓimẓum (self-contraction) of God, which he borrows from Lurianic Kabbalah. Just as the earthly world had revealed itself to be governed by exile, abandonment, failure, and powerlessness, so was the divine world equally in crisis in Luria. The unmoved mover was jolted into motion: powerless to stop evil, he must retreat from active engagement in the world. In Wiese's reading, the difference between the idea of ẓimẓum and Jonas's notion of divine impotence is that while the ẓimẓum is a temporary condition, the absence of power is permanent for Jonas. Wiese understands this as an antimessianic trope, which distinguishes Jonas from the Kabbalah and possibly also a modern form of Gnosticism. In Luria, the current state of failure is predicated on an earlier disaster—the collapse of Creation—while in Jonas, it is uncertain as to where causation begins or ends. In avoidance of a Gnostic nihilism, Jonas cannot envision a reversal of the ẓimẓum and therefore accepts the permanent state of divine impotence. The precise moment of divine retreat, however, also remains unclear and equally therefore the origins of evil.

There are some editorial problems, such as typographical errors and Germanisms, which could have been avoided by the publisher. The letter from Hans Jonas to Hannah Arendt on Eichmann (181), which is dated 1963, could not have been written before May 1964 by its own reference. However, these errors do not detract from the contribution that The Life and Thought of Hans Jonas has made to our understanding of the man and his place within German Jewish thought as a whole.