Thanks to Neurath's efforts and other factors, the Vienna Circle had achieved a considerable notoriety by 1930. For Neurath himself, this had been largely a political matter – the desire to oppose irrationalist and anti-scientific intellectual movements at a fundamental level. He (rightly) saw these movements – which were very popular with students – as broadly sympathetic to the authoritarian fascism that was gaining ground throughout Europe. He was, of course, too late; time ran out too quickly for a long-term strategy aimed at intellectual influences to have much effect. But the strategy was reasonable, and given the dimensions of the threat, Carnap was willing to support it as a matter of civic duty, though his own time-horizons were much longer. His own understanding of ‘politics’, as we saw at the end of Chapter 1, comprised not just what is usually meant by that word, or the social activities of education and scientific research, but also the provision of fundamental conceptual frameworks for human discourse.

The Vienna Circle itself realised that its programmatic rhetoric exceeded what could be rigorously argued. Its members harboured various degrees of hope about the realisability of the promises made, but everyone (except perhaps, sometimes, Neurath himself) was aware that the basis for the programme was under construction, and might not be constructible at all in the form of its present design (ca. 1930). The gaps in the Aufbau construction were acknowledged, not least by its author.