Metaphysics, understood as the study of the causes of first things, of “being qua being” or simply of that which goes beyond the physical realm, has traditionally been seen as a central topic of philosophy. But for the subjects of David Edmonds’s lively new book – the group of philosophers, mathematicians and physicists known as the Vienna Circle – metaphysics was, strictly speaking, nonsense.

At the centre of the Circle were two distinct personalities. The de facto chair of the Circle was the eponymous Professor Moritz Schlick, genteel, mathematically trained, a stickler for procedure and largely apolitical. His opposite number was Otto Neurath, the red-bearded “dervish of Vienna”, an indefatigable organizer of the intellectual and political life of left-wing Vienna, too interested in housing and public education to have much time for metaphysics (or, as some members of the Circle grumbled, basic politeness). He pioneered “isotype” representations that translated complex statistical information into simple, unornamented images, convinced that while “words divide, pictures unite”. This was the political counterpart to the philosophical conviction that came to define the logical positivism of the Circle: “metaphysical terms divide, scientific terms unite”.

According to Rudolf Carnap, the most intellectually combative member of the Circle and the man who would bring logical positivism to America after the Second World War, metaphysics divides precisely because it is nonsense. Metaphysics takes the form of vague and paradoxical “pseudostatements”, Carnap’s favourite example being Heidegger’s adage that “the nothing noths”. These pseudostatements neither describe the world nor elucidate the structure of our reasoning, but merely gesture at an idea that would not make sense were it put in comprehensible terms. They appear to say something profound, but fail to say anything at all. Metaphysicians are thus less like scientists and more like musicians or abstract artists, prompting feeling rather than knowledge. But if metaphysicians are musicians, as Carnap archly remarked, they are “musicians without musical ability”.

If there was any city that understood musical ability, it was Vienna. Before the First World War, Vienna was the capital of a multilingual, multi-ethnic empire. Each night its coffee houses became theatres of debate and exchange, where Austrian painters, Polish logicians and Czech physicists, Zionists, Catholics and revolutionary socialists argued about the intellectual events of the day. For the Circle itself, the most significant of these were two revolutions in scientific thought: Einstein’s physics of relativity and the new logic of Gottlob Frege and Bertrand Russell. The new science demanded a new philosophy: iconoclastic, empiricist and resolutely anti-metaphysical.

The scientific preoccupations of the Circle are well-documented, but Edmonds shows that the revolutionary fervour of interwar Vienna was by no means limited to logic and physics. Well-connected members of the Circle might be found at a table with Gustav Klimt or Karl Kraus discussing Bauhaus architecture just as easily as Brownian motion. Neurath, Carnap and many others were closely involved with Austromarxism and the leftist government of “Red Vienna”. The most succesful parts of the book are those in which Edmonds draws unexpected connections within the sprawling web of thinkers and artists in interwar Vienna (not many histories of philosophy have a dramatis personae after the epilogue), bringing to life the artistic and political flavour of those coffee-house debates.

Most of the circle were socialists or Jews or both, and, as Austromarxism gave way to Austrofascism, many grew increasingly anxious about the fate not only of the Circle but also of their own positions in Vienna. Enquiries were made about positions at British and American universities. Then, on June 22, 1936, as Schlick was walking from his home on the Prinz Eugen Strasse to his morning lecture, a student named Johann Nelböck leapt out from the crowd and shot him point blank through the heart. The trial was a sign of things to come. Nelböck’s initial defence was that the Circle’s anti-metaphysical philosophy had eroded his moral judgement, but after the Anschluss he issued an appeal to the Nazis, arguing that in killing “a Jewish teacher who propagated doctrines alien and detrimental to the nation” he had eliminated the rot of atheistic and immoral Jewish philosophy (notwithstanding the fact that Schlick was not Jewish). He was released on parole, celebrated not only by the mob and the clergy, but by his colleagues at the university. One of them, writing under the pseudonym “Dr Austriacus”, made explicit an increasingly widespread feeling about Jewish people and “Jewish ideas” in Vienna: “let the Jews have their Jewish philosophers at their Cultural Institute! But the philosophical chairs at the University of Vienna should be held by Christian philosophers! … It is to be hoped that the terrible murder at the University of Vienna will quicken efforts to find a truly satisfactory solution of the Jewish Question”.

A question the book raises but never quite answers is the connection between the philosophy and the politics of the Circle. Edmonds seems to agree with Carnap that metaphysics is Kampfmittel, a tool of war, used to cultivate a sense of sanctity and sublimity around notions such as “nation”, “race” or “historical destiny” to justify the sacrifice of anything (or anyone) in their defence. The metaphysics of blood and soil was philosophical nonsense, but nonsense that had a mesmeric effect on those who heard it, whether in Heidegger’s lectures or the vulgar metaphysics of the Nuremberg rallies. Such was politics, and such was philosophy in the 1930s. But do the enigmas of metaphysics always serve as tools of reaction? And is there really anything inherently democratic about empiricist demands for clarity and plain-speaking? Readers are left to make up their own minds, but for those concerned by contemporary echoes of Reichstag-storming, book-burning and right-wing extremism, the Vienna Circle’s dual commitment to logical clarity and social justice can serve as a model, in the words of Karl Sigmund, of “exact thinking in demented times”.

Jonathan Egid is a writer and teacher of philosophy. He is writing a book about the seventeenth-century Ethiopian philosopher Zera Yacob, and the question of whether or not he existed

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