For many years, this question was framed according to the “lean versus clean” debate: Should central banks “lean” against bubbles, damping down asset prices that create risks to financial stability, or just clean up the mess after bubbles burst? Proponents of the latter approach, such as former Fed Chair Alan Greenspan, express doubt that policymakers can reliably identify bubbles, and are generally uneasy about managing asset prices.
多年来，这一问题引起了一场“遏制还是清理”的争论：央行应该“遏制”泡沫，打压引起金融稳定风险的资产价格，还是等到泡沫破裂后清理混乱局面？后一个方针的支持者包括前美联储主席艾伦·格林斯潘（Alan Greenspan），该方针质疑决策者是否能可靠地识别泡沫，认为总体而言管理资产价格绝非易事。