There are two standard evaluations of Popper's importance. The first sees Popper as an important figure in the philosophy of science, one whose work is now passe, but whose influence cannot be denied. The other sees Popper as one of the great geniuses of the twentieth century, a polymath who gave us new paradigms of scientific and political thinking. This second view, while still the view of the minority, is gaining support in a new millennium where Popper is enjoying something of a renaissance. This is the view that has inspired both Bryan Magee and Antony Flew to pen histories of philosophy subtitled (surely not just for the sake of alliteration) "From Plato to Popper." And this is the view that inspires Malachi Haim Hacohen to give Popper a central place in what, despite its title, is an intellectual history of inter-war Vienna.
If Popper's importance has not been properly appreciated, suggests Hacohen, that is because we try to situate him in the Anglo-American tradition that appropriated him after the Second World War and in which he became famous. Instead, Hacohen traces the genealogy of Popper's philosophy through the currents of thought in inter-war Vienna, showing how they shaped Popper and how Popper responded to them within this context. We see how his principle of falsification evolved as a response to the logical positivism of the Vienna Circle, and how his critique of historicism and promulgation of the Open Society--though published in and appropriated by a Cold War West--were in fact inspired responses to the socio-political debates of 1930's Vienna.
Hacohen's primary aim is to give us a greater understanding, and hence a greater appreciation, of Popper's achievement. But in tracing inter-war Viennese culture more broadly, he also shows the extent to which that culture's set of concerns has shaped our own intellectual outlook thanks to the diaspora of Viennese intellectuals--many of them Jewish--in the face of the Nazi threat. The Vienna Circle influenced a generation of philosophers, Hayek has become a champion for libertarians, and Gombrich has changed the way we look at art. In all of these cases, but none more so than in philosophy, these thinkers have found success in England and America by adapting ideas born out of uniquely Viennese debates to contexts that these debates never reached.
Inevitably, our reception of these ideas on foreign shores distorted their intent. For instance, we tend to understand the Vienna Circle as Ayer understood it without appreciating how the tools and methods these philosophers developed were meant to settle the debates on the nature of science that had divided an earlier generation of Viennese thinkers, the likes of Boltzmann and Mach. Like the Vienna Circle, Popper is too often read as his English-speaking contemporaries interpreted him, and Hacohen's book gives us a rich sense of the problems and debates that shaped Popper's distinctive outlook. Hacohen has labored tirelessly in the archives, and while his preference for completeness and transparency of research over readability makes it a laborious slog, both the depth, breadth, and originality of Hacohen's scholarship is exceptional. He is more at home discussing the social sciences than the natural sciences, but he is more at home in both of these fields than most of us can ever expect to be.
The problem, then, is whether Popper is the central figure of the intellectual history of inter-war Vienna, which is how Hacohen portrays him, or if he is only one of a number of bright minds to emerge from that context, and neither the brightest nor the most influential. He was a marginal figure at that time, and his contemporaries in the Vienna Circle, though respectful, seemed not as convinced as he was that he had delivered the deathblow to logical positivism. The philosophical world more generally tends to give the role of death-dealer to Quine for his 1951 paper, "Two Dogmas of Empiricism." Hacohen might reply that we inflate Quine's importance to Popper's detriment because we come to logical positivism from an Anglo-American perspective, and that in failing to appreciate its original context, we fail to appreciate that Popper had buried logical positivism by 1934. There is some merit in this argument, and perhaps if Popper had arrived in London before 1946 and if the Logic of Scientific Discovery had been published in English before 1956, things would be different. But whether a result of historical mischance or of Popper's work not being as decisive as he thought, he has failed to have an impact on English-speaking philosophy that rivals the Vienna Circle. Or Quine, for that matter.
Hacohen makes an excellent case for the tremendous, and too-often unnoticed, influence of inter-war Vienna on post-war scholarship in the English-speaking world, but he is less convincing in situating Popper as the central figure of this influence. Popper certainly developed interesting and fertile responses to the problems of his intellectual milieu, but it seems a bit of an exaggeration to claim that he solved these problems, or even that his solutions are more compelling than those of any of his contemporaries. Hacohen does not simply state his allegiance to Popper baldly; he provides arguments, but these arguments are not likely to convince those of us who are not already Popperians.
Popper has never been fully embraced by the mainstream of Anglo-American philosophy, and this may be connected with his having been shaped by a different set of concerns than his English-speaking contemporaries. With these concerns in clearer focus, he still doesn't emerge as one of the great thinkers of the twentieth century, but Hacohen's effort to give him his due does shed valuable light on an interesting period. Though his emphasis on Popper's importance may be misplaced, Hacohen's book nonetheless makes for engaging intellectual history.