“The real thing which is the subject matter of praxeology, human action, stems from the same source as human reasoning. Action and reason are congeneric and homogeneous; they may even be called two different aspects of the same thing. That reason has the power to make clear through pure ratiocination the essential features of action is a consequence of the fact that action is an offshoot of reason. The theorems attained by correct praxeological reasoning are not only perfectly certain and incontestable, like the correct mathematical theorems. They refer, moreover, with the full rigidity of their apodictic certainty and incontestability to the reality of action as it appears in life and history. Praxeology conveys exact and precise knowledge of real things.”
Or here
“There are only exchange and nonexchange; and with regard to any exchange all the general theorems concerning exchanges are valid in their full rigidity and with all their implications. There are no transitions from exchange to nonexchange or from direct exchange to indirect exchange. No experience can ever be had which would contradict these statements.”
Action and reason are one and the same thing, so to speak. You can’t have one without the other. Furthermore, any theory, concept, or idea deduced from the axiom “Human Act”, granted the argument logically follows, is thus valid.
“There are only exchange and nonexchange; and with regard to any exchange all the general theorems concerning exchanges are valid in their full rigidity and with all their implications. There are no transitions from exchange to nonexchange or from direct exchange to indirect exchange. No experience can ever be had which would contradict these statements.”
Exchange either happens or it doesn’t. There is no halfway point. There is no such thing as half an exchange. Either I give you $1 dollar for an apple, or I don’t. The price may change, but the fact of exchange is either a yes or a no. Furthermore, there is no way that one can experience half an exchange, because it is impossible.
If the hadn’t been into such wonderful high-sounding language (one understands right away that he is either a German or French speaker from the mere tone of the writing), he could have gone like: “try to disprove that people exchange because they prefer to! See, you can’t, because that is tautological. Thus, every logically derived axiom, starting form that point alone, is just as unattackable.”