The answer to
Tuesday's yesterday's riddle (which was inspired by Thomas Presskorn's comment) is that models are to theories what norms are to practices. That is,
Models determine the meaning of a "mere" perception as an empirical fact.
That wasn't actually a very good sentence, but it was enough to suggest a solution to the puzzle.
The etymology of "norm" was helpful: '"standard, pattern, model," 1821, from French norme, from Latin norma "carpenter's square, rule, pattern".' When we turn to "model", things get even better: 'from Latin modulus "a small measure, standard," diminutive of modus "manner, measure"'. A norm is essentially an ethical standard, just as a model is an epistemic one.
It's interesting here to recall Kuhn's reflections in his post-script to The Structure of Scientific Revolutions:
...along the spectrum from heuristic to ontological models, all models have similar functions. Among other things they supply the group with preferred or permissible analogies and metaphors. By doing so they help determine what will be accepted as an explanation and as a puzzle-solution; conversely, they assist in the determination of the roster of unsolved puzzles and in the evaluation of the importance of each. (246)
Notice here the strong influence that models are said to have on what I've been talking about this month as imagination. By setting up "permissible analogies and metaphors", as well as defining relevant puzzles and acceptable solutions to them, they ultimately tell us what is to count as a "fact" in a particular area of research. [And facts are what the imagination makes us pictures of.] That's why Kuhn is right to talk about them as both "heuristic" and "metaphysical" components of paradigms. After all, what we find puzzling is the state of the facts, and only the discovery of new facts will dispel our puzzlement in a satisfying way. Models discipline the imagination.
Riffing on the etymology again, I think we can usefully think of norms as patterns in human action. It is those patterns that make our actions meaningful. And it's interesting to look at models precisely as "manners": they are are ways to experience things. Facts are really patterns in our data. And we notice some patterns and not others according the models we have been trained to use as guides ("carpenter's squares") in our analyses of our perceptions. Just as acts conform to, or push against, or even break with our norms, facts conform to, or push against, or break with our models. It's that relationship that makes them what they are.
(Notice the value of this kind of analogical reasoning. Thinking about the general features of norms, and tracing the etymology back to the Latin for a carpenter's square and pattern, we can apply these images to our understanding of models. Basically, we are noticing the "normative" aspect of models: how they influence our perceptions. We are also noticing the way norms constitute "model behavior", e.g., how the "normal" is constructed by appeal to "role models".)
The social sciences have to keep in mind that while they are, like all other sciences, primarily interested in the facts, which they derive from their perceptions according to their models, the relevance of their inquiries depends on the actions the facts bear upon. And those actions are meaningful, i.e., they become proper, socially sanctioned "acts", by virtue of the norms that are in force in a particular culture at a particular time.