What Would Keynes Have Done?

凱恩斯主義經濟學或凱恩斯主義是根據凱恩斯的著作《貨幣、利息與就業通論》的思想基礎上的經濟理論，主張國家採用擴張性的經濟政策，通過增加需求促進經濟增長。

摘自The New York Times 11/30/08 What would Kenyes Have Done? by N.Gregory Mankiw
根據凱恩斯主義, 經濟下滑的根源是來自於需求不足. 商品或服務的需求下滑--> 銷售下跌--> 生產削減及裁員...增高的失業率及獲利的下跌, 進一步的壓抑需求..如此將造成惡性循環.

原文部份內容:
IF you were going to turn to only one economist to understand the problems facing the economy, there is little doubt that the economist would be John Maynard Keynes. Although Keynes died more than a half-century ago, his diagnosis of recessions and depressions remains the foundation of modern macroeconomics. His insights go a long way toward explaining the challenges we now confront.

According to Keynes, the root cause of economic downturns is insufficient aggregate demand. When the total demand for goods and services declines, businesses throughout the economy see their sales fall off. Lower sales induce firms to cut back production and to lay off workers. Rising unemployment and declining profits further depress demand, leading to a feedback loop with a very unhappy ending.

The situation reverses, Keynesian theory says, only when some event or policy increases aggregate demand. The problem right now is that it is hard to see where that demand might come from.

The economy’s output of goods and services is traditionally divided into four components: consumption, investment, net exports and government purchases. Any expansion in demand has to come from one of these four. But in each case, strong forces are working to keep spending down.

The fly in the ointment — or perhaps it is more an elephant — is the long-term fiscal picture. Increased government spending may be a good short-run fix, but it would add to the budget deficit.

Keynesian economists often dismiss these long-run concerns when the economy has short-run problems. “In the long run we are all dead,” Keynes famously quipped.

It is hard to say how successful monetary and fiscal policy will be in avoiding a deep downturn. But as events unfold, you can be sure that policymakers in the Fed and Treasury will be looking at them through a Keynesian lens.

In 1936, Keynes wrote, “Practical men, who believe themselves to be quite exempt from any intellectual influence, are usually the slave of some defunct economist.” In 2008, no defunct economist is more prominent than Keynes himself.