The Op-Ed. is entitled “When the Scientist Is Also a Philosopher,” and it draws attention to the fact that economists’ work is “based not only on our understanding of how the world works, but also on our judgments about what makes a good society.” So: economists are both scientists, to the extent that they make falsifiable predictions about the economy; and political philosophers, in the sense that their work continues to be shaped by political and moral judgments in ways that natural scientists’ work is not. A fair enough point, as far as it goes.
But ironically, in the process of making this point, Mankiw illustrates something different. He shows the disparity between the relative sophistication of economics as a science and the relative lack of sophistication in many economists’ thinking as “political philosophers.” Mankiw’s credentials place him near the top of the economics profession in the United States. He can debate technical economic issues with a facility that few can match. But when he moves beyond these technical matters and into something like political philosophy, he loses that facility and appears blind to the unstated assumptions underlying his view of the economy.
In the central passage of the column, he writes the following: