Q&A: Karl Sigmund on the Vienna Circle

If you were living in Vienna around 1920, you would be in the midst of an extraordinary milieu of artists, philosophers, and scientists. In the center of that milieu was a group called the Vienna Circle, intellectuals whose work on the philosophy of science is the subject of a new book by University of Vienna mathematician and historian Karl Sigmund.

The Vienna Circle contained roughly a dozen academics from a variety of fields, including philosopher and physicist Moritz Schlick, mathematician Kurt Gödel, and economist Otto Neurath. They met regularly during the 1920s and 1930s and were united by, as Sigmund puts it, “the idealistic goal of forging a great unification of human knowledge.” Ultimately the circle launched logical positivism, a philosophical movement that emphasized logic and experience as the sole sources of insight.

In the June issue of Physics Today, Don Howard writes that “the way we think and talk about science today—as a way of investigating and understanding our world based on rigorous logic and empirical investigation—is largely the legacy of the Vienna Circle.” He says that Sigmund’s book, Exact Thinking in Demented Times: The Vienna Circle and the Epic Quest for the Foundations of Science, will long stand as the best account of the circle and its work. Howard describes the book as “history—serious and first-rate history—written like a novel” and calls it “a masterpiece.”

PT: You’re known for your work in evolutionary game theory. For those who haven’t heard of the field before, what is evolutionary game theory? What kinds of questions do you investigate?

SIGMUND: Game theory is the mathematics of conflicts of interest. We study decisions whose success depends on the decisions of others. Game theory can be used in the study of biological and cultural evolution to describe the ways that successful reproduction and survival strategies spread in a population. Historically, some of the first applications focused on fighting behavior in animals. But what interests me most is the emergence of moral norms through social learning—how to explain, for instance, the amazing propensity of humans to cooperate.

PT: What sparked your interest in the Vienna Circle?

SIGMUND: It was sparked by Ludwig Wittgenstein, a philosopher of mathematics and language who fascinated me when I was a schoolboy. I got over that crush, but I still cannot make up my mind about his work or about him as a person—and when I found that the Vienna Circle had exactly the same problem with Wittgenstein, I instantly felt drawn to them. Today the members of the circle are pigeonholed as “logical empiricists,” but that label does not do justice to their diversity, their internal and external fights, their turbocharged philosophical environment, and their dramatic individual fates. They were right in the middle of an amazing philosophical firework, one that sent Ernst Mach, Ludwig Boltzmann, Karl Popper, and Wittgenstein soaring into the sky.

PT: How did living in Vienna influence your work on Exact Thinking in Demented Times?

SIGMUND: It influenced me tremendously. The Vienna I grew up with, in the 1950s and 1960s, was very close to the Vienna of the circle and at the same time utterly different. My office was on the same corridor as the room where they met, my coffeehouses were theirs, and some of my older teachers had known them personally. At the same time, the Vienna of my youth was an intellectual wasteland, the “town without Jews,” as novelist Hugo Bettauer had predicted in the 1920s.

PT: The members of the Vienna Circle were working in a politically and intellectually tumultuous era. Do you think their story holds any lessons for our own times?

SIGMUND: “Demented times” strikes a chord, for sure. But we must be careful not to be carried away by our propensity to recognize patterns everywhere. History is not a morality play, and its parallels never extend very far. What strikes me more, in fact, are the differences. For instance, doing science today—with project funding, PhD programs, and impact factors—has a very different feel from what it was 40 or 80 years ago.

PT: What is your next project?

SIGMUND: Einstein’s Vienna, a TV documentary created by my wife and me. It’s almost finished. Albert Einstein was in Vienna only five times, each time for a few days only—but he had close ties with a tremendous number of Viennese scientists, including the thinkers of the Vienna Circle. When I wrote my book, I was surprised to see Einstein shoulder his way into each chapter. He was the intellectual hero of the circle—that was one of the very few things they all agreed upon. And the film is not only about science, but also, alas, about two murders. It will be a documentary, but one in the guise of a film noir.

PT: What are you reading?

SIGMUND: Lately I have been rereading a dozen biographies of Einstein. And right now, I am reading The Age of Wonder: The Romantic Generation and the Discovery of the Beauty and Terror of Science by Richard Holmes. Let’s face it: Science is for romantics.