It has been obvious for quite a while that Sanders — not just his supporters, not even just his surrogates, but the candidate himself — has a problem… - Paul Krugman

In this part of the lecture I have argued that a number of works in development economics written during the 1950s contained, more or less explicitly and more or less self-consciously, a theory in which strategic complementarity played a key role in development: external economies arose from a circular relationship in which the decision to invest in large-scale production depended on the size of the market, and the size of the market depended on the decision to invest. Whatever the practical relevance of this theory, it made perfectly good logical sense. Yet this was subsequently abandoned, to such an extent that classic papers in the field began to seem, as the physicist Wolfgang Pauli used to say, "not even wrong" — simply incomprehensible.

I do not think this is a permanent condition. The craziness comes more from cultural ethnic issues than anything else, because you have a… A lot of the real craziness come from, if you like, from rural who feel that they’re losing their country, they’re losing ownership of the country. And they are right—we are becoming more diverse, more multicultural. And in the end... they are not the future. In the end, the power they still have will go away. But it’s a very difficult time until then. So the future is Mayor Deblasio of New York, but Ted Cruz is still out there with the ability to do a lot of damage.

The problem is that there is no alternative to models. We all think in simplified models, all the time. The sophisticated thing to do is not to pretend to stop, but to be self-conscious—to be aware that your models are maps rather than reality.