Objective Consistency

There's a tendency with diagrammatic thinking, one Peirce succumbed to as well, to discuss it in terms of science.  Mark Twain [in Life on the Mississippi] describes what he calls the "science" of being a steamboat pilot on the  Mississippi River in the late 1800s.  The amount of knowledge was immense, one way up the river, another going down, and constantly changing as the river changed. What's more, as with all non-tacit diagrams, the pilot had to "see" it. As Mr. Bixby put it:

NO! you only learn THE shape of the river, and you learn it with such absolute certainty that you can always steer by the shape that's IN YOUR HEAD, and never mind the one that's before your eyes. [p. 103]

Twain called what he was learning a "science", yet, unlike modern science, it concerned itself with only one particular object, the Mississippi River.  In fact, as the object, the river played the crucial role of underpinning the internal consistency of the diagram as well as the inferences being made using it.  It provided an objective assurance that a conflict resolution procedure would not be needed in applying the rules.  Rather than saying such knowledge is not really "science", that it is not diagrammatic because it is not generalizable, it might be better to realize that the modern sciences, and other more general kinds of diagrams, must maintain the same kind of internal consistency without that anchor in a particular object.