Chapter 19 concludes the book and analyzes the importance of the notion of synthesis for Tinbergen. Synthesis for him was a unity in moral and scientific perspective, and he admired most those economists and social reformers who were able to combine scientific insight with moral vision and practical action. The chapter analyzes the extent to which Tinbergen’s own work and efforts represent such a synthesis. It is suggested that his personal goals of peace and harmony were only partially integrated with his scientific economics. These elements coexisted, which meant that he left a fragmented legacy. His contributions to scientific expertise and its institutionalization, however, had the most long-lasting influence. And although expertise proved hard to combine with his own high-minded idealism, it is demonstrated that what attracted economists like Tinbergen to a role as policy expert was precisely the belief that social goals could be pursued through economic policy. The goal for control through rational planning of economic policy also fitted his personality well, and thus best captures the Tinbergen synthesis.

Chapter 1 uses the construction of the Peace Palace in The Hague around 1910 as metaphor for his intellectual project. The Peace Palace was the tangible outcome of two consecutive international conferences on international law in Tinbergen’s birthplace. The conferences were an initiative of nineteenth-century imperial powers, but provided an important impetus to the international legal, and later economic, order that would come to characterize the twentieth century. In a similar way Tinbergen’s work is marked by a tension between older nineteenth-century historical state-centered perspectives on the economy and modern twentieth-century techniques and scientific tools. The theme of peace and the construction of an international order were central to Tinbergen’s intellectual project. And like the Peace Palace, his project was characterized by a tension between high-minded idealism and political realities. Most importantly, the city of The Hague as diplomatic center in a small country, dependent on international trade and peace, provides a helpful lens through which to understand Tinbergen’s oeuvre.

Chapter 7 is one of three chapters that reflects on the rise of economic expertise during the twentieth century. It places the development of Tinbergen’s econometric techniques within a broader political context in which political parties during the middle of the twentieth century moved away from ideological and class-based foundations and toward general interest parties, known as people’s parties (or in German Volksparteien). This generated a demand from within politics for a new type of economic expert, who served no longer as party ideologues, but rather as policy experts. This was most visible in the social-democratic parties, such as the Dutch SDAP, which transformed in the PvdA (Labor Party). During the same period economists presented themselves increasingly as experts to the state, who could scientifically pursue the general interest. These developments run counter to the more widely known story about economics becoming a value-free science as proclaimed by Lionel Robbins. The chapter argues that Tinbergen’s contributions are best understood as a continuation of the German tradition of Staatswissenschaften, which pursued economics in service of the state.

Chapter 14 analyzes the political-economic context of Tinbergen’s work as development planning expert in Turkey between 1960 and 1966. Tinbergen was brought in against the will of the Turkish government, at the urging of the OECD and the IMF. After the military coup later that year, he played a key role in the founding of the State Planning Office as well as its institutional design. The SPO was modeled after the Dutch CPB, and how its political setting differed from the planning bureau in the Netherlands is analyzed. Many of the development planning efforts of the SPO were met with hostility in Turkish politics and in the economy. The chapter traces how Tinbergen sought to navigate these tensions, frequently unsuccessfully. He hoped to create space for economic expertise above the parties, as he had successfully done in the Netherlands, but structural reforms necessary according to the planning experts quickly became part of the political struggle within the country between the more traditional and liberal agricultural interests, and the more progressive and planning-minded industrial interests. The chapter highlights the importance of the international planning ideology and economic interests of the West in shaping the outcomes of Tinbergen’s efforts in Turkey.

Chapter 16 is the third of three chapters to reflect on the rise of economic expertise during the twentieth century. In this chapter the debate surrounding Gunnar Myrdal’s book Asian Drama is used to position Tinbergen in the debates about development planning and neocolonialism. The critique of Myrdal’s book by anthropologist Clifford Geertz is used to contrast the way in which economic expertise developed in the Netherlands, and how it was imposed in former colonial countries by the international community. It is argued that an important set of preconditions such as social integration, broad political parties (people’s parties), and a strong civil society that made the success of economic expertise possible in the Netherlands were absent in many of the developing countries in which Tinbergen worked. The chapter concludes with an analysis of Tinbergen’s universalism, which had attractive moral features, but ran into limits as a program of economic policy.

Chapter 11 is the second of three chapters reflecting on the rise of economic expertise during the twentieth century. It utilizes the famous Lucas critique of econometric models to explore the role and position of the economic expert and economist. It demonstrates how central Tinbergen’s decision models were for the Lucas critique, which was framed completely in Tinbergen’s terms. The critique was mostly justified since the models of Tinbergen implicitly relied on an asymmetry between the policymaker making decisions and other economic actors making decisions. That asymmetry is mirrored in Tinbergen’s perspective on public and expert knowledge, and the role of experts in a democratic society. Lucas correctly identified a crucial tension between democratic ideals and expert decision-making, but he also incorrectly equated changes in decision variables with changes in the institutional structure of the economy, and therefore made the world (too) flat. In conclusion, it is useful to distinguish between the economist concerned with the comparison of alternative institutional arrangements and the economic expert concerned with policy decisions. Both strands are shown to be present in Tinbergen’s work, who at times wrote as economist about institutional design and at times as policy expert about optimal policies.