Edited and written by David Gordon, senior fellow of the Mises Institute and author of four books and thousands of essays.

Checking Premises

Winter 1999

David L Prychitko
Research in the History of Economic Thought and Methodology
Volume 16 (1998), pp. 241-58

In the course of a largely appreciative review of Murray Rothbard's An Austrian Perspective on the History of Economic Thought, David Prychitko, who has long positioned himself as an anti-Rothbardian, makes a few mistakes worthy of attention. Our author, as a hermeneuticist in good standing, must get in at least a few shots at "a leading Austrian of the doctrinaire Misesian wing, with its insistence on apodictic theoretical truths" (p. 243).

What better way to disconcert a supporter of deductivism than to show that he stands guilty of logical error? Rothbard, it seems, "burns entire schools of thought (Ricardian, Walrasian, and Keynesian being his favorite sacrifices) as necessarily false and useless simply because they incorporate descriptively false assumptions.... This suggests that Rothbard remained misinformed about basic logic" (p. 252).

How has Rothbard lapsed into mortal sin? He has ignored the elementary fact that false premises need not entail false conclusions. Mr. Prychitko is perfectly correct that valid reasoning from false premises need not transmit falsity to the conclusion. But Rothbard has made only a trivial slip; and the main point he endeavors to make in the passage our author attacks is both true and important.

Rothbard's target was the system of David Ricardo, which, in his view incorporated false assumptions "into the initial axioms" (p. 256, quoting Rothbard). A deductive system begins with certain initial axioms and from them derives various theorems. It is the truth of the initial premises that guarantees the truth of the conclusions. Without true axioms, our deductive system stands on air.

The conclusions of the deductive system may, given false premises, turn out to be true. But the fact that they can be derived from false premises gives us no reason to think that they are true. Thus, Rothbard's sin was venial and his basic point insightful. Ricardo aimed at establishing certain propositions deductively. If his axioms are false, he has failed. Rothbard is right that such deductions are "useless and misleading."

I fear that Mr. Prychitko's grasp of logic is itself not above reproach. He writes "[K]nowing only the truth or falsity of the first premise does not inform us of the truth or falsity of the conclusions" (p. 252). But if your premises are true, then whatever validly follows from them is also true. The principle that valid inference transmits truth from premises to conclusions is the whole basis of the deductive method. I hope that our author does not consider this basic principle of reasoning to be doctrinaire.

A few other points in Mr. Prychitko's essay warrant mention. Why does he think that if, during the "scholastic culture of High Catholicism...scholars and theologians were struggling with the basic presuppositions of early Catholic faith and the dynamic competitiveness of nascent capitalism" (p. 257), this shows that the scholastics had not established a paradigm in economics? If our author is right, the scholastics struggled with the ethical justification of capitalism: this is entirely consistent with holding an agreed-upon account of economic theory. Mr. Prychitko may deny this, I suspect, because he thinks that questions of value cannot be separated from factual issues. But this view is his and not Rothbard's, and he should not take for granted its truth in criticizing him.

Further, why does our author suggest that Rothbard held, nonsensically, that "radical milleniallism among the Anabaptists" was "an early effect of Calvinism" (p. 248)?


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