In Austrian economics as it has been developed through Mises ‘rationality’ is synonymous with ‘goal-directed conduct.’
It is a formal definition with no reference to the particular goal sought and no reference to the means utilized.
It is not the same conception of rationality as that used by objective/normative ethics and objective/normative moral theories.
The notion that the Austrian definition of rationality might be trivial or meaningless probably rests on the premise that tautologies are ‘empty’ or meaningless. But tautologies need not be considered empty or meaningless.
24 = 2 x 12 = 4 x 6 = 3 x 8 is tautological. But three groups of eight may not be immediately apparent upon an apprehension of twenty four.
Logical or tautological reasoning fleshes out the implications of given suppositions, and these implications are important for action and life.
Aprioristic reasoning is purely conceptual and deductive. It cannot produce anything else but tautologies and analytic judgments. All its implications are logically derived from the premises and were already contained in them. Hence, according to a popular objection, it cannot add anything to our knowledge.
All geometrical theorems are already implied in the axioms. The concept of a rectangular triangle already implies the theorem of Pythagoras. This theorem is a tautology, its deduction results in an analytic judgment. Nonetheless nobody would contend that geometry in general and the theorem of Pythagoras in particular do not enlarge our knowledge. Cognition from purely deductive reasoning is also creative and opens for our mind access to previously barred spheres. The significant task of aprioristic reasoning is on the one hand to bring into relief all that is implied in the categories, concepts, and premises and, on the other hand, to show what they do not imply. It is its vocation to render manifest and obvious what was hidden and unknown before. (Human Action)
In the Misesian conception, just as mathematics expounds the tautological implications of 24, praxeology expounds the tautological implications of goal-directed conduct or rationality or intentionality or human action (all terms here considered synonymous).
“The analytic method is simply a way of discovering necessary consequences of complex collocations of facts—consequences whose counterpart in reality is not so immediately discernible as the counterpart of the original postulates. It is an instrument for “shaking out” all the implications of given suppositions. Granted the correspondence of its original assumptions and the facts, its conclusions are inevitable and inescapable.”
(Robbins, An Essay on the Nature & Significance of Economic Science)
In Austrian economics, at least in the Misesian interpretation, the fundamental original assumption is that an actor faces a situation that he is attempting to replace with a different situation. The attempt to change the situation he is confronted with to a different situation is called ‘rational action’ or simply “rationality.” The study of the formal implications of rational action results in a science of ‘given relations.’ which means a science that instructs on what must accompany a given situation should it occur. E.g., the law of marginal utility expressing a relationship between an actor coming into a supply or unit of supply, and a ‘value’ experience that accompanies his coming into that supply.
Normative ethics, whether of the state, of the right, or of the left, must attack praxeology and value-free social science (usually disparaged as ‘utilitarianism’) because these provide a comprehensive framework for understanding social phenomena while not offering any support to the normative conclusions and “objective” values that the state, the right, or the left, want to enforce.
Value-free social science is seen as an enemy by objective and normative ethics, since value-free science is a rival paradigm that explains social phenomena comprehensively with no room left for classifying those with whom we disagree as immoral, evil, and criminal.
“Bewildered, people had to face a new view of society. They learned with stupefaction that there is another aspect from which human action might be viewed than that of good and bad, of fair and unfair, of just and unjust.”
“Human action and social cooperation seen as the object of a science of given relations, no longer a normative discipline of things that ought to be—this was a revolution of tremendous consequences for knowledge and philosophy as well as for social action.”
(Human Action)