A striking characteristic of economic policymaking in this country is our fascination with the ephemeral and our neglect of long-range problems. A lot of passionate commentary, for example, has been devoted to the slowing of the growth rate of real G.N.P. to 3.8 percent in the third quarter. Yet if the past is any guide, that figure, when finally revised, will turn out to have been in error. The slowdown may have been much smaller than reported, and quarterly fluctuations in the growth rate are in any case largely beyond our control. The U.S. economy does not respond like a yo-yo to every push or pull on the string called economic policy.