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 8 analyzes his work for the League of Nations, which resulted in the first macro-econometric model of the US economy. The League’s Economic and Financial Section was a hub of economic expertise in the 1930s. Before Tinbergen arrived, Gottfried Haberler had produced an overview of the business-cycle theories. This chapter argues that the projects of Haberler and Tinbergen are best understood as outcomes of joint work under the supervision of Arthur Loveday and Dennis Robertson, with the help of assistants, coauthors, and expert committees. Although commissioned and published under the names of particular authors and understood as monographs, the studies are attempts to create expert consensus. A detailed study of the Tinbergen report demonstrates at once the various coauthors and internal critics involved and the contested nature of virtually all aspects of the study, as well as the potency of this new teamwork, without which the study would have been impossible. That this report was meant to forge expert consensus means that the critique of John Maynard Keynes of both studies should be understood partly as a challenge to the League of Nations as an institution, and partly to this new type of consensual expert knowledge more broadly.

Chapter 9 details Tinbergen’s activities during World War II when he was working at the Central Bureau of Statistics. It uncovers crucial details about his relationship to the German occupiers and the peculiar deal he struck with them, in particular, Ernst Wagemann, to maintain some degree of independence for the institute. It also seeks to understand his attitude toward fascism, which he strongly condemned at a personal level, but whose economic policies he repeatedly praised in his writings, both before and during the war. The restrictions imposed on research at the CBS during the war meant that Tinbergen could not continue his studies into the business cycle, which had been declared a relic of the past by the Germans. In response to these restrictions Tinbergen wrote some of his more systematic work in economic theory and economic growth, further removed from policy. What is most striking is that precisely during the turbulent 1930s and 1940s a notion of an autonomous economic system emerged in his work. This detachment from politics and society is analyzed in detail. The chapter closes with a discussion of his efforts during the early Reconstruction years as director of the newly founded Central Planning Bureau.

Chapter 17 analyzes his efforts, throughout his scientific career, to measure welfare. Measurement was crucial for his intellectual program. While measurement often succeeded in his early career with the development of business-cycle statistics, the measurement of welfare remained unattainable. The measurement of welfare was important because it would allow a scientific comparison of the welfare levels between different individuals, and thus of the degree of inequality. He wanted to use that as a basis for his scientific notion of justice. In his efforts he went against a general consensus in economics that interpersonal comparisons of welfare were beyond the reach of economic science. Tinbergen took up a chair in Leiden after his retirement and attempted to develop a collaboration with Bernard van Praag and Arie Kapteyn, but their joint approach found little support in the wider economics community. Nonetheless, the failure is interesting because it provides insight into the way in which moral concerns became more important later in Tinbergen’s career, how crucial measurement was to him, and because his attempts foreshadowed later approaches in economics to measure capabilities and happiness. Most importantly, it demonstrates how he hoped that science could inform normative concepts such as justice.

Chapter 13 analyzes his contributions to development economics. It is argued that his central contribution is not an economic theory of development, but rather a technique for development planning. Tinbergen’s work on planning is mainly concerned with implementing development plans, which he argued should be done using his three-stage planning model, consisting of the macro phase, the industry phase, and the project phase. Later work expanded this model to include regional planning and education planning. After the initial period between 1955 and 1960, most of Tinbergen’s work on development economics was increasingly about a vision of an integrated world economy. It is demonstrated that econometric and analytical work moved to the background and that his visionary and institutional work moved to the foreground. Crucial in his vision of the international economic order was his experience in the Netherlands. The chapter shows how his vision of the international economic structure crucially relied on analogies with the national economic order. The chapter concludes with some early reflections on his development economic work and suggests that it largely disregarded the ethos of self-help and emancipation that Tinbergen knew from his youth in the AJC.

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 15 situates his work during the Cold War and the debate about convergence between the economic and political systems in the East and West. Tinbergen’s argument for coexistence of the two nuclear powers and economic systems is analyzed. This thesis of coexistence is later developed by Tinbergen into a theory of convergence, which is not rooted in economic or sociological theory, but is primarily a moral argument about the (search for an) optimal order. His idea of the optimal order is analyzed, in particular, to emphasize how deeply he had become an institutional thinker. The chapter also discusses various international interactions of Tinbergen in Indonesia, Spain, France, and elsewhere with military leaders and regimes to explore the consequences of his desire to always engage in conversation and to avoid conflict. These limits are further explored in a critique of his convergence thesis by his daughter and son-in-law. The chapter concludes with an analysis of an exchange between Oskar Morgenstern and Tinbergen about the role of the economist during the Cold War. Morgenstern worked for the US military to optimize military strategies, whereas Tinbergen argued that economists should direct their efforts to promoting peace.

Chapter 2 describes the family in which he grew up. Both his parents were teachers, and his father Dirk Cornelis was a quite prominent figure in The Hague. Dirk Cornelis Tinbergen held a PhD in Dutch medieval literature and was part of progressive educational milieu that sought to renew pedagogical methods and the Dutch spelling. His mother stayed home after she had children, but she stimulated the societal awareness of Jan Tinbergen. He had four siblings, two of which also pursued scientific careers. Luuk and Niko Tinbergen were both successful biologists; Niko won a Nobel Prize in physiology and medicine in 1973, four years after Jan Tinbergen won the Nobel Prize in economics. It is argued that the family was an example of Bildungsbürgertum. In the education of the children there was ample attention to culture and the study of nature. Unlike his brothers, Jan had little appetite for outdoor life and from a young age was more drawn to the exact sciences and modern industry, in particular, the trams in The Hague.

Chapter 10 argues that the central contribution of Tinbergen is his decision models, which conceive of economic policy as the relation between instruments and goals. The chapter analyzes the way in which the original econometric models of the 1930s were transformed by Tinbergen (and Ragnar Frisch) into models for policymaking, in response to their new state positions. Tinbergen was director at the Central Planning Bureau in the Netherlands, which developed into the premier economic policy institute there. The transformation of econometric models into decision models no longer treated policy as a given, but instead treated behavioral economic relations as given, and the policy variables as decision variables, placing the economic expert inside the model. The chapter explores this fundamental transformation, and how it impacted Tinbergen’s own view of economics. He no longer believed that the primary goal was to describe the economic structure, but rather to design of (optimal) decision models to pursue targets. This was true at the firm and state levels. He sought to redefine crucial concepts such as unemployment and business cycles in policy terms. Finally, he used that transformation to analyze the optimal level of decision-making in the economy, a crucial insight for his later work.

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 5 details the transformation from the cultural socialism of Tinbergen’s youth to the more political socialism of the Plan Movement. Crucial throughout this transformation was the work of the Belgian Hendrik de Man, who was both the most important intellectual for the cultural socialist youth movement (AJC) and the leader of the Plan Movement in Europe. De Man’s early work was critical of Marxist theory and sought to reconcile bourgeois cultural ideals with an idealistic interpretation of socialism. But during the Great Depression, and especially after the early successes of fascism in various European countries, De Man and other social democrats strongly felt that an immediate response to the economic crisis and the political challenge of fascism was required. Although Tinbergen never became as politically involved as de Man, he was one of the main architects of the Dutch Plan of Labor. This Plan proposed a number of crisis measures, such as public works, but also sought to secure a permanent place for economic expertise within the Dutch state. The chapter concludes with an analysis of the anti-parliamentarian and anti-democratic elements in the Plan movement.

Chapter 12 describes Tinbergen’s transformation from a national economic expert to an international development economist. While involved in domestic matters in the early 1950s, a trip to India affected him deeply. Afterward he reoriented his career, asked permission to leave the CPB, and developed a new research agenda. That new agenda went hand in hand with a redefinition of the role of the Netherlands in the world in the aftermath of colonization. Tinbergen argued that it was the responsibility of the Dutch people to give something back to the world after the country had received Marshall aid and was again a stable economy. The most visible outcome of this was his involvement in the founding of NOVIB. He worried that social democracy in Western Europe was turning into a complacent and materialistic movement and hoped that international goals would give it a new spirit. He drew on his extensive network in Dutch politics and the Royal family to shape development aid policies at home and to transform himself from a national into an international economic expert. This aligned with a reimagination of the economy, which he increasingly viewed as an international interdependent system, under the influence of Colin Clark.

Chapter 18 analyzes his work after his retirement in Rotterdam, in particular, on international governance. The first part of the chapter demonstrates that in response to frustrated attempts to further integrate the international community, Tinbergen became more radical and ambitious. He promoted a global government and international order along the lines of the developments that had taken place at the national level. He became more critical of the short-sightedness of both political leaders and voters and grew more critical of democracy. The second part of the chapter analyzes the underlying perspective of Tinbergen about the fallibility of man and the need for economic order. His view of humans is shaped by his Protestant, in particular, Remonstrant, beliefs, and he believed that (economic) order in the form of rules and institutions was required because humans are flawed. Harmony and peace must be actively constructed. The chapter suggests that next to a deep-seated sense of responsibility there is an element of fear in Tinbergen’s outlook. In his later works these fears and worries come more into the foreground, and he became pessimistic about the future, but he tried to remain hopeful.

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 4 analyzes Tinbergen’s scientific coming of age under the mentorship of the physicist Paul Ehrenfest. Tinbergen started his studies in mathematics and physics in 1921 in Leiden where he encountered some of the leading physicists of the age, such as Heike Kamerlingh Onnes and Ehrenfest. Especially the latter helped turned Leiden into a lively scientific hub with innovations in the curriculum, teaching methods, and his famous inquisitive seminars, which earned Ehrenfest the title the Socrates of Leiden. From 1923 onward Tinbergen was mentored by Ehrenfest, who guided his studies in both physics and economics. The chapter details the difficult choice that Tinbergen had to make between these two fields, as well as the shared vision that Tinbergen and Ehrenfest developed about the role of science and scientists in modern society. In 1929 Tinbergen completed his dissertation in physics, which already contained some analogies between physical and economic phenomena. In the following years Ehrenfest stimulated Tinbergen’s statistical research in economics, which soon became part of the new field of econometrics. The two would host the meetings of the Econometric Society in 1933, but just days before, Ehrenfest would take his own life.

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.

Chapter 6 analyzes the trajectory from his early econometric studies to the macroeconomic model he completed in 1936. During this period, he worked at the Central Bureau of Statistics and the Netherlands Economics Institute, to develop new methods to study business cycles. That research was linked to a network of similar institutes across Europe in London, Vienna, Paris, Berlin, and beyond. The chapter demonstrates how the analysis of the dynamics of particular markets provided inspiration for a study of the dynamics of the overall economy. The goal shared by many theorists of the age was to arrive at a dynamic economic theory, as opposed to the static equilibrium models of classical economics. Tinbergen sought to identify the relevant mechanism that could explain the type of movements typically seen in the overall economy: business cycles of about eight years. But the chapter argues that there was also an iterative dynamic between the political and policy issues of the time and Tinbergen’s work, which was never purely scientific or disconnected from practical concerns. The chapter concludes with a sketch of the main characteristics of his econometric work: the dynamic nature, the combination between theory and empirics, the substantive institutional emphasis, and the way in which Tinbergen believed that quantitative econometric studies could help overcome theoretical and political differences.

Chapter 3 analyzes the tension between his bourgeois upbringing and his socialist convictions. In his early twenties Tinbergen went through his most radical period in which his socialism was fostered within the social-democratic student clubs, the Workers Youth Movement (Arbeiders Jeugd Centrale, AJC), and the pacifist milieu. He sought to identify closely with the fate of the workers. Through Tinbergen’s review of the novel A Middle-Class Man (Der Bürger) by Leonhard Frank, about a bourgeois man who seeks to join the socialist struggle, the tensions in his life and work during this period are explored. The chapter details how Tinbergen tried to find his own role, and that of his fellow students, in the fight for socialism. This involved finding the right response to Marx, exploring modern approaches in economics, and identifying the way in which he could contribute most to the socialist cause. Initially, he believed this would mean becoming one with the workers and the workers’ movement, but within a few years Tinbergen distanced himself somewhat from these movements, and became convinced that modern scientific economics was the way forward.