A Praxeological Theory of Interest Rates

Abstract

This paper starts with the observation that the pure time preference theory leads to conflicting views concerning the effect of changes in productivity on the rate of interest. Subsequently, it reviews parts of the interest literature and concludes that the pure time preference theory does not qualify as a praxeological theory. Then, the paper combines Hülsmann’s theory of interest with the subjectivist capital theory of Lachmann and Kirzner and provides a praxeological theory that explains the rate of interest. The key to that theory is that cost reduction through the use of fixed capital must always be understood as relative to the costs of labor which the capital replaces. Since labor is non-specific and the price of labor therefore also constitutes the production costs of fixed-capital goods to a certain extent, the use of fixed capital necessarily entails a business surplus somewhere in the economic system. Since this surplus cannot dis-appear it qualifies as interest income. The size of this income is such that the interest rate corresponds to the marginal rate of substitution between labor and fixed capital as embodied in entrepreneurial actions.