Assessing a Diagram

Christopher Sims gave this definition of scientific thought.

"Advances in the natural sciences are discoveries of ways to compress data concerning the natural world — both data that already exists and potential data — with minimal loss of information." [p. 1]

Originally, it seems to me, the goal of the "natural sciences" was explanation, and then at some point that was reduced to "prediction", and now, apparently it's simply a matter of fitting past and future data to data-compressing correlations.  Whether for explanation, prediction, or fit the procedure may be diagrammatic, but assessing the consequences as a measure of diagrammatic thought, especially as the sole measure, seems to get increasingly rickety.  Later Sims laments:

"I think many economists now see themselves as experts in persuasion as much as experts in substantive knowledge.  They are willing to use arguments they know are flawed without explaining the flaws or to cite evidence they know could be shown to be misleading, for the sake of rhetorical effectiveness." [p. 9]

The diagrammatic purpose can only be realized in the motives of individuals users, and the reliance on assessing the consequences by itself is not much of a guarantee.  As Peirce wrote regarding the economics of research:

"It is to be remarked that the theory here given rests on the supposition that
the object of the investigation is the ascertainment of truth.  When an investigation is made for the purpose of attaining personal distinction, the economics of the problem are entirely different.  But that seems to be well enough understood by those engaged in that sort of investigation." [CP 7.157]

The economics of the diagram, the benefit versus the cost of using it, is the second measure, playing off the diagram's adequacy to its purpose.  These considerations determine whether we'll use a diagram or not, but there's a lot of slack in such determinations.  And, I don't think artificially adding the "ascertainment of truth" as a stipulated purpose will take up that slack.  We need to look at the consistency of the diagram itself, the inferences made within it, and the assumptions it makes.  We need to tighten things up between the experience to which it applies and the consequences which it then explains, predicts, and/or fits.