And finally, no matter how good the science gets, there are problems that inevitably depend on judgement, on art, on a feel for financial markets.
First, I think the science of monetary economics has clearly gotten better.
A second reason why science cannot replace judgement is the behavior of financial markets.
Increased government spending can provide a temporary stimulus to demand and output but in the longer run higher levels of government spending crowd out private investment or require higher taxes that weaken growth by reducing incentives to save, invest, innovate, and work.
But because we in the United States finance our current account deficit by borrowing in our own currency, we can move to a more competitive dollar without the adverse effects that followed currency declines in other countries.
To finance this trade deficit, the U.S. has to borrow from the rest of the world or sell American assets like stocks, businesses, and real estate to the rest of the world.
The only way that we can reduce our financial dependence on the inflow of funds from the rest of the world is to reduce our trade deficit.
A rise in the level of saving can reduce aggregate activity temporarily but only a sustained high level of saving makes it possible to have the sustained high level of business investment that contributes to the long-run growth of output.