Alan Greenspan, the former Federal Reserve chairman, writes in his new book, “The Map and the Territory,” that he has been thinking about bubbles since the financial crisis of 2008. Specifically, he has been trying to understand why he and so many other economic forecasters failed to see the housing bubble that caused the crisis.

The mistake, he writes, is that forecasters treated humans as rational decision makers — a functional fiction that no longer seems functional. But Mr. Greenspan sees a way forward: Humans, he writes, are irrational in predictable ways. What economists like to call “the animal spirits” can be incorporated into economic models.

“I have recently come to appreciate that ‘spirits’ do in fact display ‘consistencies’ that can importantly enhance our ability to identify emerging asset price bubbles in equities, commodities and exchange rates — and even to anticipate the economic consequences of their ultimate collapse and recovery.”

This is promising stuff. It might even make an interesting book. But the subject barely holds Mr. Greenspan’s attention for a single chapter.