海耶克景氣與資本結構理論之重建

THE HAYEK THEORY OF TRADE CYCLE AND CAPITAL STRUCTURE RECONSTRUCTED

海耶克／哈耶克（Friedrich A. Hayek）結合奧地利學派迂迴生產（round-about production）理論與Wicksell累積過程論之難題在於，無法內生地確定產業垂直分工的均衡結構。本文導引垂直分工的中間產值函數，發現加工過程中持有中間投入的利息成本累進遞增，構成迂迴分工程度的自然限制，可解此一難題。Hayek理論強調利率、物價與資本結構的失衡調整過程，在上述基礎上修訂、重建之景氣理論，足以證明：一、動態安定系統之「Hayekian總和供給曲線」為負斜率，二、貨幣擴張政策不具長期實質效果，終將導致停滯性膨脹（stagflation）與資本錯置（misdirection of capital）。

The key problem of Hayek’s theory of trade cycle, which combines Wicksell’s cumulative process and the Austrian theory of roundabout production, is how to determine the equilibrium capital structure of a vertically specialized industry endogenously. This article asserts that interest costs of the intermediate input increase progressively along the round-about process and form a natural constraint to the degree of specialization. This settles the Hayek problem. Furthermore, by synthesizing disequilibrium dynamics of the price and the capital structure, this study reformulates the Hayek theory and shows that: (1) the Hayekian aggregate supply curve in a system that is dynamically stable has a negative slope; (2) expanding monetary policies are ineffective in the long run, and inevitably end in stagflation and misdirection of capital.