There is plenty to be said for seeing the world through an economic prism but one of the downsides of the dismal science is what it does to your levels of enthusiasm for new ideas. Much of economic history consists of people making mistakes, forgetting them, rebranding the old failed ideas and making the same mistakes all over again.

How does one square this with the claim one sometimes hears that this is an unusually fertile moment for economics? Consider some of the big new ideas in economics today: the universal basic income (UBI), modern monetary theory (MMT) and cryptocurrencies. Might any of them actually shift the needle?

Let’s start with crypto. It is probably the easiest of the three to write off, given the