Emil du Bois-Reymond (1818–1896) rose to the pinnacle of German science during the same epoch that German science rose to preeminence in the European academic world. A pioneer in the study of electrical currents in nerves and muscles, du Bois-Reymond made seminal contributions to the mechanistic view of life, holding that matter and motion, not mystical vital forces, suffice to explain all organic processes. He later became a professor of physiology, an institute director, and rector at the University of Berlin, helping to build what is now recognized globally as the progenitor of the modern research university. Both these roles, and his position as secretary to the Prussian Academy of Sciences from 1876 until his death, served as public springboards to assert the authority of science as the royal road to truth in the modern age. Today, however, few non specialists appreciate du Bois-Reymond's huge impact, in part because his materialist approach to neuroscience has simply become common sense. The challenge for the modern biographer is to evoke the inner life of a scientist who believed that nerves and muscles alone explain our thoughts and actions. The enigmatic relationship between neuroscience and the self, between public career and inner life, is the focus of Gabriel Finkelstein's study. It offers—but does not demonstrate—the claim that its subject was “the most important forgotten intellectual of the nineteenth century” (xv).

After an early dalliance with Romantic Naturphilosophie and its woolly notions of organic vital development, du Bois-Reymond became a student of Johannes Müller, who held the chair of anatomy and physiology at the University of Berlin. Part of an all-star cohort of pioneering life scientists dubbed “Müller's Lab” in the eponymous book published by Laura Otis in 2007, du Bois-Reymond counted among his colleagues Theodor Schwann, architect of the cell theory of life; Rudolf Virchow, the founder of modern pathology; and the polymath Hermann von Helmholtz. “Animal electricity” became du Bois-Reymond's own area of expertise. Following Luigi Galvani and Alessandro Volta, who gave us the words “galvanize” and “volt,” as well as the now-forgotten Carlo Manteucci, du Bois-Reymond spent countless hours hooking up frog legs to electrodes to make them twitch. He then had to prove that such effects were not artifacts of his experimental apparatus, or byproducts of the tissue injury caused by dissection, or reconfirmations of some unknown vital force that was not a true electric current. Thanks to his precision instruments and careful hypothesis-testing, du Bois-Reymond surpassed not only his Italian but also his French and English contemporaries. Finkelstein follows him from his cramped Berlin laboratory to public appearances in Paris and London—where he encountered haughty skeptics in the former city and enthusiastic dilettantes in the latter—during the 1850s, when German science had begun to challenge its western rivals. Along the way, as Finkelstein relates in great detail, the scientist fell in love, got married, and settled down to a prosperous and contented family life.

The second half of du Bois-Reymond's career was notable less for his further scientific discoveries than for a highly influential series of public speeches delivered from his twin perches as university professor and secretary of the Prussian Academy. It was in these speeches, later published for a wide readership, that du Bois-Reymond assimilated the progress of science to the triumph of liberalism, nationalism, and civilization itself. He celebrated Prussia's scientific and educational accomplishments after its defeat of France in 1871; canvassed world history to reveal that, among human institutions, only science registered true improvement; and issued a bracing defense of Charles Darwin, who, as a modern Nicolaus Copernicus, had displaced humanity from the center of the world. And yet, his two most penetrating speeches—”The Limits of Science” (1872) and “The Seven Enigmas” (1880)—are distinguished as much for their epistemological humility as for their scientific triumphalism. It is striking that although he advocated the ultimate “resolution of natural processes into the mechanics of atoms” (265), du Bois-Reymond steadfastly denied that science could ever fully accomplish this goal. The fantasy that one could, in principle, calculate the fate of the universe if one only knew the disposition of every atom would still never reveal the essence of matter, let alone of life. So, too, consciousness, sensation, thought, and free will would always remain a mystery. Ignorabimus (we shall never know) became the slogan by which du Bois-Reymond was remembered. His was a stance that proclaimed the superiority of science over religious obscurantism, yet he judiciously refrained from endorsing a fully disenchanted, deterministic view of life in the universe. His views exposed him to blistering controversy and conservative rebuke, but he remained a happy warrior to the end—consistent with his happy private life as a successful academic and family man.

Finkelstein's biography is rich in details, as well as insights, particularly about the mixture of rivalry and comradeship among career-focused academics in Germany and beyond. The book remains more a descriptive biography than an analytical one, however. Long anecdotes on family life and career struggles shed little light on the key philosophical and epistemological concerns of the age. Analytical statements, when they do come, often come abruptly, and would have benefited from more careful preparation, unpacking, contextualization, and evidentiary grounding. Examples include Finkelstein's remarks on identity and epistemology, on the common threads of “experience” binding marriage and work (170), and on “functional analysis” (230) as the master key to du Bois-Reymond's science. Certain critical experimental techniques and terms—tetanization and negative variation—are insufficiently explained. All this leaves the reader unsure about exactly how the world looked before du Bois-Reymond changed our understanding of it. Finkelstein ultimately does not succeed, then, in integrating his subject's neuroscience into his life story, let alone in framing the wider analysis of “self and society” needed to secure du Bois-Reymond's place in the nineteenth-century intellectual pantheon.