Clarifying Further What The A Priori of Argumentation Is

I was rereading a section of The Economics and Ethics of Private Property by Hans-Hermann Hoppe and found the correct definition of the a priori of argumentation. In the past I have simply said that the definition is “One cannot consistently argue that one cannot argue,” but I only had it half right.

The second axiom is the so-called “a priori of argumentation,” which states that humans are capable of argumentation and hence know the meaning of truth and validity…The validity of the axiom, like that of the action axiom, is indisputable. It is impossible to deny that one can argue, as the very denial would itself be an argument…One cannot argue that one cannot argue. Nor can one dispute knowing what it means to make a truth or validity claim without implicitly claiming the negation of this proposition to be true. [emphasis mine]