Mitchellians, Keynesians, and Marxians Are Convinced That Business Cycles Spring from Deep within the Capitalist System

Yet, on closer analysis, the common reaction is by no means self-evident. It rests, in fact, on an unproven assumption—the assumption that business cycles in general, and depressions in particular, arise from the depths of the free-market, capitalist economy. If we then assume that the business cycle stems from—is “endogenous” to—the free market, then the common reaction seems plausible. And yet, the assumption is pure myth, resting not on proof but on simple faith. Karl Marx was one of the first to maintain that business crises stemmed from market processes. In the twentieth century, whatever their great positive differences, almost all economists—Mitchellians, Keynesians, Marxians, or whatnot—are convinced of this view. They may have conflicting causal theories to explain the phenomenon, or, like the Mitchellians, they may have no causal theory at all—but they are all convinced that business cycles spring from deep within the capitalist system.

--Murray N. Rothbard, introduction to the first edition of America's Great Depression, 5th ed. (Auburn, AL: Ludwig von Mises Institute, 2000), xxxviii.