Semantic Consistency

I don't know that we would want assert that all languages are tautological.  Logic certainly is, and perhaps mathematics, to the extent it is not axiomatically related to experience.  But it seems a bit strong to say something like "economic language" is made up of only tautologies.  More generally we might refer to a "semantic consistency" whereby the indices and relationships of a diagram, while they may be inspired by experience, are defined relative to one another within the confines of the diagram itself.  And where the consistency of a diagram is semantic — unlike where it is objective or axiomatic — the application of the diagram becomes a more pressing question.

Friedman's answer to this question is:

"[T]here inevitably will remain room for judgment in applying the rules.  Each occurrence has some features peculiarly its own, not covered by the explicit rules.  The capacity to judge that these are or are not to be disregarded, that they should or should not affect what observable phenomena are to be identified with what entities in the model, is something that cannot be taught; it can be learned but only by experience and exposure in the "right" scientific atmosphere, not by rote. It is at this point that the "amateur" is separated from the "professional" in all sciences and that the thin line is drawn which distinguishes the "crackpot" from the scientist." ["The Methodology of Positive Economics," p. 25]

This is no more than "common sense," what Deleuze called the "process of
recognition" that precedes "good sense", "the process of prediction" [Difference and Repetition, p. 285] deployed on a scientific level.  It is based upon an education in "the 'right' scientific atmosphere;" in particular, it is based on the specialization of "professional" schooling where an instrumental confinement to the diagram is embedded as a way of life. [see, "Re-Imagining the Academy: Louis Menand"] The problem is that it blinds its adherents to alternative diagrams, to there even being alternative diagrams, to different interpretations of the same situation, and it allows the importation of diagrams, with often tragic results, into situations where they do not apply.  Any diagram is a selective abstraction, one among several, and there is always the question whether it applies or not.