But if the Fed has only one effective instrument – interest rates – its two goals of economic and financial stability cannot be pursued simultaneously. Either the Fed pursues the first goal by keeping rates low for longer and normalizing them very slowly, in which case a huge credit and asset bubble would emerge in due course; or the Fed focuses on preventing financial instability and increases the policy rate much faster than weak growth and high unemployment would otherwise warrant, thereby halting an already-sluggish recovery.
可如果美联储只有利率一种有效工具，经济和金融稳定的两大目标就无法兼顾。美联储或者通过长时间压低利率及缓慢正常化在实现第一个目标的同时制造出巨大的信贷和资产泡沫；或者侧重于防止金融动荡，比增长乏力和失业率高企所能允许的限度更快地提升政策利率，从而导致本已缓慢的复苏陷入停滞。