Abstract

Axel Leijonhufvud’s On Keynesian Economics and the Economics of Keynes (1968) definitely belongs to the category of “classic” books. Its message—decentralised economies are prone to large increases in unemployment since communication failures prevent the optimal coordination of private decisions—is by now well understood. In this paper, we argue that even though most commentators correctly identify this message, they overlook two crucial aspects of Leijonhufvud’s demonstration. These aspects relate to what the author calls the “aggregative structure” and the “transaction structure” of macro-models. We show that the former type of structure plays a central role in the emergence of unemployment in the “Economics of Keynes”, while the latter type of structure explains why unemployment is “involuntary”.

摘要

Axel Leijonhufvud的《凯恩斯主义经济学和凯恩斯经济学》（1968年）无疑属于“经典”书籍。它的信息是：由于通信失败阻碍了私人决策的最佳协调，去中心化经济体容易导致失业人数大量增加。在本文中，我们认为，即使大多数评论员正确地识别了此消息，他们也忽略了莱昂霍夫夫德的示威游行的两个关键方面。这些方面与作者所说的宏观模型的“集合结构”和“交易结构”有关。我们表明，前一种类型的结构在“凯恩斯经济学”中失业的出现中起着核心作用，而后一种类型的结构解释了为什么失业是“非自愿的”。