Adam Smith's uncritically enthusiastic modern disciples portray his invisible hand theory as saying that market forces reliably harness selfish individuals to serve the common good. That's often true, but as Darwin recognized clearly, many traits that serve the interests of individual animals make life more difficult for larger groups.

Getting the economy back on its feet is properly viewed as an investment in future prosperity. When businesses and consumers confront attractive investment opportunities, often the only way to seize them is by borrowing. The same is true for government. Contrary to the pronouncements of critics of economic stimulus, these investments will not impoverish our grandchildren. Continuing to allow the economy to languish in recession is the surest way to impoverish them.

When the rich build bigger, they shift the frame of reference that shapes the demands of the near rich, who travel in the same social circles. Perhaps it's now the custom in those circles to host your daughter's wedding reception at home rather than in a hotel or country club. So the near rich feel they too need a house with a ballroom. And when they build bigger, they shift the frame of reference for the group just below them, and so on, all the way down.

When people bump up against one another in the course of pursuing their goals, it is in everyone's interest to resolve any resulting problems in the least costly ways possible.

As John Maynard Keynes taught us in the 1930s, in such situations, government is the only entity with both the motive and the ability to boost total spending by enough to put people back to work. As it happens there are long lists of important public projects that cry out to be done.

We could curtail private spending by several trillion dollars a year without requiring painful sacrifices from anyone. That would be more than enough to rebuild our crumbling infrastructure and eliminate government indebtedness once and for all.

If the search is for examples that contradict the predictions of standard economic models, a good rule of thumb is to start in France.