Paul Krugman Quote

Economics is harder than physics; luckily it is not quite as hard as sociology. Why is economics such a hard subject? Part of the answer has to do with complexity. The economy cannot be put in a box. [...] Another reason economics is hard is that the critical sociologist is right: it involves human beings, who do not behave in simple, mechanical ways.

Preface - Peddling Prosperity (1994)