But we should be able to ask:  “What are the arithmetical rules that connect measurable circumstances to abstract math?”
	Arithmetical rules that work should be logically and experimentally consistent when we test them. But what we are referring to, in detail? ….. Are “measurable circumstances” and “pure math” different?   ……… Do they use just the same kinds of numbers, subject to just the same rules?  …… Does it matter?   If we are to understand how physical effects couple together, it sometimes does matter, and we’ve got to look at some simple things that we aren’t in the habit of attending to.