Jan Tinbergen was and is of course a scientist, full of curiosity about how the world works. But his motivation has always been more than curiosity. He wants to know how the world works so that he can make it work better. Knowledge is the foundation of policy. It was natural for Tinbergen to set forth a formal theory of policy nearly ﬁfty years ago and it was equally natural from him to relate the theory to practical problems of policy in the Netherlands and else where and to implement it and illustrate it with the help of theoretical and econometric models. Thus Tinbergen was the originator of the subject on which I propose to speak to you today.
Tobin, James, "On the Theory of Macroeconomic Policy" (1989). Cowles Foundation Discussion Papers. 1174.