Paul Mendes-Flohr spent four decades on modern Jewish thought; his final book, Love Is Strong as Death: A Biography of Franz Rosenzweig, was completed a year before he died in October 2024. Rosenzweig is the “anti-Kant” — a philosopher of comparable depth whose life was lived rather than merely thought: a German-Jewish scion who nearly converted to Christianity, came back to Judaism on Yom Kippur, and kept writing as ALS slowly paralyzed him.
The biography rests on unpublished material — Rosenzweig’s “Black Book” diary and over a thousand “Gritli letters,” a seven-year epistolary romance with his best friend’s wife:
- His philosophy rejects “old thinking”: God, human, and world are irreducible, bound through creation, revelation, and redemption; revelation’s core command is “Love me.”
- The title comes from Song of Songs — for Rosenzweig the “focal-book of revelation,” where human eros and divine eros are continuous; Gritli became the “locus theologicus of revelation.”
- Eugen Rosenstock-Huessy, who coined “a communism of love” for the triad, judged the letters “more important than the whole Star.”
- Rosenzweig and Kafka as doppelgängers: German-speaking Jews at the height of prewar continental culture, both dead young of disease, spared the Nazi conflagration — both extraordinary letter-writers.
The book is not for general readers — “misologistic” and “irrefragable” go undefined. But the review argues it may finally begin Rosenzweig’s introduction to the wider world: Kafka long ago escaped Central European Jewish letters; Rosenzweig, partly by design, hasn’t yet. This biography may be the start of that introduction, but it will not be the last word.