Ludwig M. Lachmann, “The Science of Human Action” (1951)

Lachmann’s essay is an extended review of Mises’s Human Action, but it is also a methodological interpretation of Austrian economics after Weber, Menger, and Hayek. He begins by stressing that Mises’s book cannot be treated as a narrow technical treatise, because its argument joins economic theory to a wider account of social order, ideology, and rational inquiry.

Its majestic sweep embraces almost the whole field of economics and touches, at some point or other, on almost every social issue of our time.

The organizing distinction is between “Catallactics,” the analysis of market exchange, and the broader “Praxeology,” the science of human action. Lachmann reads Mises as defending the autonomy of the social sciences against positivism: action is intelligible because it is purposive, plan-guided, and structured by categories such as means, ends, choice, cost, and time. These categories are not empirical generalizations in the manner of physics; they are presupposed in the very recognition of conduct as action.

There is therefore such a thing as a Logic of Action closely linked to the logic of our thought.

This does not make economics empty formalism. Lachmann’s most important emphasis is that Mises’s system is a theory of processes rather than of static states. Equilibrium constructions may clarify tendencies, but they cannot substitute for explanations of how acting persons revise plans under uncertainty. Market coordination depends on interpretation, learning, and entrepreneurial judgment. Profit and loss are therefore not merely distributive categories; they are signals that sort successful from unsuccessful anticipations and continually reallocate control over resources.

Lachmann’s sympathy with Mises’s apriorism is qualified by his insistence that economics must recognize different layers of experience. The basic categories of action are not tested like hypotheses about measurable regularities, yet the concrete application of economics concerns historical markets, changing knowledge, and uncertain expectations.

They are not subject to verification or falsification on the ground of experience and facts.

The essay then links methodology to capital theory. Lachmann presents Mises as moving beyond homogeneous conceptions of capital and beyond the older “average period of production” doctrine. Capital goods form a heterogeneous, time-structured order whose value depends on their place in entrepreneurial plans. This is why the market process cannot be reduced to simultaneous equations: the central problem is the continual recombination of complementary assets in light of imagined futures.

In this way what we have come to regard as the main body of economics is seen to belong to two related but distinct fields.

That capital-theoretic perspective grounds Lachmann’s account of socialism and the trade cycle. Socialist calculation fails not simply because planners lack arithmetic prices, but because they lack the entrepreneurial capital market in which assets are regrouped, tested, and revalued. Likewise, the Austrian theory of the cycle is not a crude claim about “too much” investment. Credit expansion distorts the capital structure, encouraging projects for which the necessary complementary resources are unavailable. The crisis reveals discoordinated plans rather than mere deficient demand.

The closing movement of the essay treats Mises as a critic of egalitarian and bureaucratic illusions. Lachmann does not present this as an optional political appendix but as an extension of the theory of action: specialization, inequality of judgment, and entrepreneurial selection are intrinsic to the market order. His Mises is therefore not only a defender of laissez-faire, but a theorist of how knowledge, plans, prices, and capital combinations are coordinated through time.