Ludwig von Mises and the Theory of Capital and Interest

Kirzner’s essay reconstructs Mises’s theory of capital and interest from scattered writings and seminar influence rather than from a single systematic treatise. Its central claim is that Mises’s mature position is not simply Böhm-Bawerkian, but a radicalized Mengerian subjectivism: capital is a category of monetary calculation, while interest is rooted in time preference rather than in the physical productivity of capital goods.

STUDENTS OF MISESIAN ECONOMICS often agree that the theory of capital and interest occupies a central and characteristically Austrian position in the general Misesian system.

Kirzner begins from the apparent tension between the importance of these topics in Misesian economics and Mises’s relatively limited direct publication on them. The essay therefore reads Mises’s position through Socialism, Human Action, and related discussions, emphasizing how his treatment of capital and interest follows from broader praxeological commitments. Interest is not a yield mechanically produced by machines, land improvements, or roundabout techniques; it is the market expression of the universal preference for sooner over later satisfaction. Because production takes time, future goods and the factors expected to yield them are discounted in present valuation.

The key conceptual move is Mises’s separation of capital from capital goods. Capital goods are concrete, heterogeneous means of production arrayed in time; capital is not such a physical stock but an accounting concept made possible by money prices and entrepreneurial calculation. Kirzner stresses that this definition protects Austrian theory from treating production as an automatic technical process rather than as a structure of plans.

Thus, capital is properly defined as the subjectively perceived monetary value of the owner’s equity in the assets of a particular business unit.

This also explains Mises’s distance from Böhm-Bawerk. Kirzner does not deny Böhm-Bawerk’s importance, but he argues that Mises purified the Austrian tradition of residual objectivism. The average-period-of-production idea and productivity-flavored explanations of interest still leaned too heavily on technical features of production. For Mises, time enters economics prospectively, through the actor’s comparison of alternative future-oriented plans, not through an independently measurable physical magnitude.

Nor does the concept of a totality of capital goods provide any insight into the productive process.

Kirzner’s contrast with Clark and Knight sharpens the point. The Clark-Knight view treats capital as a permanent fund capable of yielding a continuous income stream, but Mises rejects this as obscuring the temporal, appraised, and entrepreneurial character of production. Factor prices already embody expected future contributions to consumer goods; productivity may explain why more goods are available, but it cannot explain why present goods command a premium over future goods.

Knight correctly characterized Mises as taking an extreme Austrian position on interest by refusing to attribute any explanatory role to the objective, or physical, conditions governing production in a capital-using world.

The essay concludes by linking capital theory to entrepreneurship. In pure theory one may distinguish capitalist, entrepreneur, and factor owner, but in actual markets these roles are inseparable. Maintaining capital, lending, investing, and reorganizing production all involve uncertainty-bearing and judgment. Observed returns therefore mix originary interest with entrepreneurial gain or loss. Kirzner’s larger contribution is to show that Mises’s theory makes capital intelligible only within a market order of monetary calculation, and makes interest intelligible only through subjective valuation across time.