How mathematical should economics be?

Manmohan Singh on economics (LSE, 2006):

In more recent decades we see excessive specialization in social sciences, and economists fancy themselves to be social engineers and technocrats. But we must never forget that economics began, after all, as political economy. Economic policy making has always involved political choices since it has political consequences. IG belonged to a generation that recognized this ground reality. He knew that the choices our economists were recommending for adoption by our country had to be marketed in the political marketplace of a functioning democracy. It was not enough that these choices were rational, or that their costs and benefits could be measured. It was not enough that the arguments were intellectually consistent or were mathematically tested. In a democracy such choices had to be also politically defendable and acceptable.