The ‘theoretical developments initiated by Haberler but named for Pigou’ do not provide sufficient grounds for rejecting ‘Keynes’s key theoretical proposition’
检验了弗里德曼在美国经济学会主席演讲中提出的一个论断，即哈伯勒发起但以庇古命名的理论发展足以否定凯恩斯的关键理论命题。经过仔细审视，该论断被证明是错误的，即使在弹性价格世界中，也没有合理理由认为系统会自然趋向充分就业均衡。
This paper examines a claim made in the introduction to Milton Friedman’s Presidential Address to the American Economic Association and that is now taken for granted in orthodox economics. According to Friedman, ‘the theoretical developments initiated by Haberler but named for Pigou’ provide sufficient grounds for rejecting Keynes’s ‘key theoretical proposition’ and the economics of Keynes in its entirety. The problem with this claim is that it turns out, given the scrutiny that it clearly deserves, to be false. The ‘theoretical developments initiated by Haberler but named for Pigou’ do not provide sufficient grounds for rejecting Keynes’s ‘key theoretical proposition’, and thus the economics of Keynes as a whole. There is no legitimate rationale for believing, in other words, even ‘in a world of flexible prices’, that the system will tend naturally toward ‘a position of equilibrium at full employment’.