What to call the fact that science traffics in assumptions?

I regularly teach a course called Understanding Science, an introduction to some issues in philosophy of science and science studies. One topic is the nature of inference: deduction, the fact that scientific inference is (largely) non-deductive, and the problem of induction.¹

A related point is that scientific inference is always informed by relevant background beliefs— which you might call background assumptions or background knowledge, depending on whether you want to endorse them. Following John Norton, I call this the material theory of induction. As Norton writes, “there are no universal inductive inference schemas. The inductive inferences of science are grounded in matters of fact that hold only in particular domains, so that all inductive inference is local.”²

In recent years, I’ve pivoted from mentioning the material theory of induction to emphasizing it as one of the important take home lessons of the course. It makes lots of other features of science follow as natural consequences: fallibilism, the Duhem-Quine thesis, inductive risk, etc.

This leaves me with a rhetorical problem. Given connotations of the word “theory”, it can sound to students as if the material theory of induction is a conjecture or speculation. It is not.³

So, is there a better thing to call this fact?

I’m currently mulling over the material fact of induction. Maybe the materiality of induction.

Suggestions are welcome.

1. I wrote a short thing for that part of the course; available as an open education resource.
2. See Norton 2003.
3. There is room for some philosophical debate, but the material theory is mostly right even if not utterly true. Most ampliative inference depends on assumptions about the stuff in question. Universal schemas are insufficient for most of science.