A 'Walrasian post-Keynesian' model? Resolving the paradox of Oskar Lange's 1938 theory of interest
深入解读奥斯卡·兰格1938年关于利率的晦涩论文，通过两个图形模型展示其投资函数的非线性及均衡解的意义，并重构兰格对资本主义经济慢性次优性的看法及其对社会主义经济的科学支持。
This article investigates Oskar Lange’s 1938 article, ‘The rate of interest and the optimum propensity to consume’, with the intention of providing a thorough interpretation of this rather obscure work. I explore in depth Lange’s theory of interest and its relationship with both Keynes’s General Theory (1973a) and Hicks’s synthesis (1937), developing two graphical models that show the non-linearity of Lange’s investment function as well as the consequentiality of his equilibrium solution. Through an unedited manuscript, I also reconstruct Lange’s beliefs about the chronic sub-optimality of the capitalist economy and his scientific endorsement of the socialist economy. I conclude that the purposes of Lange’s article predate and are independent of the General Theory. They consisted of a theoretical generalisation and analysis of institutional data, intended to separate economic theory from the tacit assumption of a capitalist economy.