「長期」と「短期」のマクロ経済モデルと金融の不安定性 : ポスト・ケインズ派金融不安定性分析の位置づけと評価(<特集>ポスト・ケインズ派経済学の新たな展開と現代的課題)

抄録

There has been antagonism between neo-classical and Keynesian macroeconomics since the 1980s. Neo-classical economists have criticized the IS-LM model for reasons such as lacking a microeconomic foundation and assuming price stickiness. Neo-classical and Keynesian economics also hold differing theories of interest rate. In short, neo-classical economics adopts the saving-investment theory of interest rate determination, whereas Keynesian macroeconomics adopts the liquidity preference theory. Mankiw (1992) proposed a macroeconomic model in the short and long run. He interpreted the IS equation as the saving-investment theory of interest rate and the LM equation as the quantity theory of money. Romer (2000) and Taylor (2004) presented another macroeconomic model in which a monetary policy rule was introduced in place of the LM equation. Romer (2000) and Taylor (2004) abandoned any differing theory of interest rate between neo-classical and Keynesian economics. On the other hand, Minsky (1982; 1986) who was a heavyweight in post-Keynesian economics proposed the financial instability hypothesis, which emphasized how the complicated financial structure underlying the capitalist economy generates business fluctuations and cycles. Many non-neo-classical economists have developed his idea following Taylor and O'Connell (1989) who proved that an economy would fall into a financial crisis when a decline in expected profit rates aggravated the financial condition of firms and increased households' preference for liquidity. Recent studies by Asada (2006) and Ninomiya and Sanyal (2009) have incorporated the dynamic equation of debt burden of firms into nonlinear economic dynamic models to indicate the financial condition. Following Rose (1969) and Okishio (1986), Ninomiya (2007c) adopted the loanable fund theory and discussed financial instability in an oligopolistic (or short run) economy. This paper examines financial instability in macroeconomics in the short and long run. We adopt the loanable fund theory to integrate neo-classical and Keynesian economics in order to evaluate the post-Keynesians' analysis of financial instability.