This is a very readable, comprehensive history of the Vienna Circle, nicely complemented by pictures of many of the members and associates of the Circle and relevant places in Austria and elsewhere.
Although the Vienna Circle has always been known to me as a philosophical community, it really had its roots in the work of physicists Ernst Mach and Ludwig Boltzmann. Mach and Boltzmann were broad thinkers, concerned not only with theoretical issues within physics but also with questions about what exactly physicists were doing when they observed and theorized. Mach famously opposed metaphysical realism, and metaphysics in general. Mach was, by my reading, much more epistemologist than metaphysician, with an emphasis on sensory impressions — what physicists do is observe by way of their senses and construct theoretical representations that allow us to understand our sensory impressions. Sigmund terms such concepts as atoms, force, and mass for Mach as “intellectual props.”
Boltzmann, while every bit the proponent of scientific understanding that Mach was, adopted a much more realist interpretation of science and its concepts. The two collided in a public debate over the reality of atoms. Boltzmann argued for a realist interpretation of atoms, even though, as Mach emphatically pointed out, no one had ever seen one. The debate focuses down on the question of sense impressions, or more loosely, direct experience. The question at the heart of the matter was the foundation of scientific knowledge, with Mach insisting that all of science rest ultimately on sense impressions. Boltzmann, while having no more patience than Mach with philosophical metaphysics, insisted that such fundamental concepts of science expressed what “really” existed.
The members of the Urkreis, the "Protocircle" that preceded the Vienna Circle itself, grew up intellectually under the influence of Mach and Boltzmann. Two core figures of the Urkreis, Hans Hahn and Otto Neurath, would go on to become founders of the Vienna Circle itself. Again, neither of the two was a philosopher, Hahn being a mathematician and Neurath an economist. But both held to what would become central tenets of the Vienna Circle — a rejection of philosophical metaphysics and strong convictions behind the priority of the empirical sciences.
The Vienna Circle itself promoted the “scientific worldview” from 1924 through the aftermath of World War II. It formed under the leadership of Moritz Schlick, philosopher at the University of Vienna, along with cofounders Hahn and Neurath. Two philosophical positions were consistent throughout the lifetime of the Circle — a rejection of philosophical metaphysics and a conviction that scientific knowledge be grounded in direct observation.
The Circle carried broad influence, beyond its actual members, touching and being touched by a who’s who of the intellectual times — Albert Einstein, Bertrand Russell, Ludwig Wittgenstein, David Hilbert, Kurt Gödel, John von Neumann, Richard von Mises, Friedrich von Hayek, Robert Musil, and on and on. Maybe the Circle’s most noted philosopher, Rudolph Carnap, produced seminal works on the logical structure of science, treating logic as the connective tissue of scientific reasoning, separate from its content.
Sigmund’s telling of the tale of the Circle is historical much more so than philosophical per se. He rarely enters into in-depth philosophical discussions or criticism of the positions taken by members of the Circle, but rather a history of those positions, debates surrounding them, the Circle’s historical context, and the personal histories of its members.
All of those dimensions have interesting, entertaining, and curious aspects, including professional jealousies and competitiveness, personal and political agendas, and even murder (the shooting of Schlick by his former student, Johann Nelböck). Neurath in particular was a bigger-than-life character and probably pushed the Circle closest to political issues and positions.
And of course, the collision between the Circle and the Anschluss in 1938 scrambled the careers, personal lives, and in some cases the political convictions of the Circle’s members. The Circle did survive the war, but the Nazification of Austria and its intellectual life meant that a number of the Circle’s members would lose their academic positions, face political and personal pressures, and in some cases, become refugees.
Sigmund is not a philosopher (he is a mathematician), so I’m not going to fault him too strongly for not engaging in philosophical points with a critical eye.
I think it would be interesting, though, to go more deeply into an important tension in the thinking of members of the Circle, Carnap in particular. Those two principal tenets of the “scientific worldview” held, on the one hand, that scientific knowledge be grounded in observation, and on the other that philosophical metaphysics was not just a waste of time, but literally meaningless exactly because it was not grounded in the kind of observations and statements about them that scientific knowledge was grounded in. It’s one thing, though, to make a claim about the grounding of scientific knowledge and very much another to claim that anything that doesn’t adhere to the defining criterion of scientific knowledge is literally nonsense. If correct, that latter claim would seem to brand not only philosophical metaphysics but probably most of what people say when they speak as gibberish.
As it turns out of course, this narrow view of language and meaning was part of the criticism that Wittgenstein leveled against his own earlier work (the Tractatus), which was revered by many within the Circle, in his later thinking (represented by his Philosophical Investigations) and distanced him increasingly from the thinking of the Circle.
Readers should be aware that the relatively casual but caustic dismissals of thinkers of a different vein than the Circle’s members — e.g., Hegel, Heidegger, Feyerabend, even Kant — should not be taken at face value. Carnap’s famous paper on the The Elimination of Metaphysics Through the Logical Analysis of Language — a polemical attack on Heidegger’s metaphysics — is, at least to my reading, a paradigm of philosophical non-engagement.
That said, I definitely recommend the book, as an historical account of the Vienna Circle if not a philosophical treatment of the positions taken by its members. For a book of intellectual history, it reads very fluidly (partly due to Sigmund’s having translated his own German edition into English, with help from Douglas Hofstadter). I had wanted to know much more of the facts about the Circle, its own history and its place in the broader history of its time, and about the members personally. I got that.