The Murder of Professor Schlick is not preponderantly focused on the killing and death of Professor Moritz Schlick. The perpetrator, weapon, and other facts of this detestable killing and shocking crime are known. David Edmonds’ clear, informative, and multifaceted study situates the murder within the rise and fall of the Vienna Circle, as his title indicates. The murder is a concentrated case of conflicting forces in radical reactionary Vienna. The Vienna Circle was a distinguished and vital circle, in a culture replete with them. The delineation of the social forms of intellectual life is a strength of this book. For example, Edmonds’ discussion of the coffeehouse is rich and friendly. Cheerful, collegial intellectuality is embodied in this book, as it often was in the life of the Vienna Circle, even as it met increasing, ultimately violent, opposition. The circle as a cultural form, its emergence and maintenance, growth or decline, is a valuable feature of The Murder of Professor Schlick.

Key members of the Vienna Circle, such as Hans Hahn and Otto Neurath, who had met regularly for a few years (1907-1912) before the Great War, came together again in 1922, after Moritz Schlick assumed Ernst Mach's professorship in natural philosophy at the University of Vienna. By 1924, they had a regular meeting place in the Mathematics Institute on the Boltzmann Gasse. Schlick was German and had connections in the English-speaking world but settled in Vienna and became the convenor of the circle which grew from early, somewhat informal discussions. Circles—private meetings to intentionally discuss economics, psychology, mathematics, literature, and any number of subjects—abounded in Vienna in part because the University of Vienna and other institutions featured lectures but little to no discussion or even interaction between students and teachers. Circles included graduate students, faculty, professionals, journalists, and persons of high academic training and accomplishment who were not fully employed, one reason for this being antisemitism. Circles collected and fed intellectual energy and excitement, locally and internationally. Eager creators and thinkers in a crisis-ridden Europe, in Vienna which was the capital of a smallish state after having been the center of an historic, multinational Empire, discussed set topics. In the circle managed by the peace- and propriety-loving Professor Schlick, they discussed in a decorous manner. To attend the circle, one had to be invited, and those deemed by Schlick to be obstreperous, such as Karl Popper, were not. The circle discussed Ludwig Wittgenstein's Tractatus from 1925-1927, and although Wittgenstein was invited, he declined. Privately he met with Schlick and some others, including Friedrich Waismann. Waismann wrote expositions of Wittgenstein's work, which ultimately proved to be more a burden than a boon to Waismann, who was demoralized by his failures to meet the standards of his philosophical hero.

The defined membership engaged in harmonious discussion, although over the years antipathies developed, such as, for example, that between Schlick and the exuberant polymath Otto Neurath. Neurath was politically active; Edmonds calls him a “Marxamite” (133), a combination of Marxist and Benthamite, an advocate of the working classes concerned with happiness for all. Moritz Schlick was not political and wished to avoid overtly political pronouncements from the Vienna Circle. He and Neurath continued in the circle, demonstrating a tolerance of disagreement that was increasingly absent in society at large. Despite differences among circle members, they were strongly engaged in their common project, logical empiricism. The Vienna Circle sought to puncture the metaphysical and the ineffable. Propositions that were verifiable by empirical evidence or within the limits of the statement itself were what they accepted as meaningful. Philosophy was to work in tandem with science to clarify problems and enhance understanding of scientific truths. For example, with psychoanalysis a prominent feature of Viennese cultural life, they debated in what ways it was a science. They were interested in strengthening the natural and social sciences by applying common criteria to validate their discoveries.

In 1929, when circle members feared that Schlick would leave for a German or American professorship, they wrote a manifesto of their aims in science and society. The Vienna Circle was a private society; they published their manifesto under the aegis of the Ernst Mach Society, which was formed in 1927 and whose officers by 1928 were the prominent members of the Vienna Circle. Schlick was president of the Ernst Mach Society. Although touched by the tribute Schlick recognized the manifesto to be, he was bothered by its polemical cast and felt that it was an unnecessary provocation, given the political climate. Upon the conclusion of the Austrian Civil War in 1934, Schlick was called by the Viennese police to answer questions about the Ernst Mach Society. Schlick wrote three testimonials defending the interest of the society in unpolitical science, but the society was disbanded. The Vienna Circle continued to meet, although less regularly, for a few more years. Austrofascism was certainly inimical to the interrogation of tradition or the disparagement of the mystical, which were the lifeblood of the circle, so some members left Austria in 1934, others later. (Kurt Godel left only in 1940.)

Edmonds details the philosophical debates of the circle and the philosophers with whom they were connected. Also notable are his biographical portraits of circle members. Otto Neurath's life is fascinating and will be of great interest to readers. One of the few illustrations in the book, which is not a photograph, is of a Neurath isotype. Neurath pioneered the pictorial renditions of information to communicate with foreign-language speakers or the unschooled. In Europe and the Soviet Union, he established museums with pictorial renditions of economic, scientific, and historical information. Icons of men and women on bathroom doors have become so pervasive that we hardly think of their originator, Otto Neurath. Edmonds’ story is not a “great man” history, as he includes for example Esther “Tess” Simpson who worked at the Academic Assistance Council in Britain, helping academic refugees, including a number from the Vienna Circle who had fled the Continent. (The end of the book provides biographical portraits and a chronology, useful in keeping philosophical, political, social, and other lines of the story clear.)

The Vienna Circle was upended, finally, by the murder of Professor Schlick, although if not by that, it would have been by something else in an increasingly Nazified Vienna. Hans Nelböck, criminally paranoid and blaming his failures on his former teacher Schlick, shot him and later used Nazi ideology (e.g., Schlick's philosophy was unpatriotic) as a defense, which got him out of jail in two years. Schlick was not in the first instance killed because of ideology, although the brutally contentious atmosphere of Vienna was the matrix for the murder. No member of the circle was killed by the Nazis, although some had a hard life in exile. They helped each other in various ways, intellectually and personally. Their philosophical profile has receded, because much like Neurath's isotypes, some of their main values of clear language and rigorous logic were pervasive in philosophy and intellectual work. The challenges they faced with growing authoritarianism, polarization, irrationality, racism, and violence are not gone from our world, and their efforts, successes, and failures are, still of intense interest.