On a language teachers’ list, the comment recently appeared:

Maybe we need to  distinguish between input-based strategies and TPRS techniques, as well as “approaches”  vs. “methodologies.”

This is something I’ve been trying to do on some of the “other lists” when engaging non-CI-based folks in dialogue about what we do. This is how I cut up the cake:

Philosophy — the basic beliefs a teacher has about what makes language acquisition happen. I prefer to label this a Philosophy and not an Approach since it really has to do with some deeply-held beliefs, in the cases where the teacher has had or has taken the time to really think about what makes the whole language thing happen.

1.  CI-based Teaching — comprehensible input causes acquisition when applied in sufficient amounts. Acquisition is what causes proficiency in the language.
2.  Rules-and-Output Teaching: having students learn (or overtly figure out, but in any case be able to state and manipulate) rules leads to proficiency, which can be reinforced by having them manipulate the rules to produce output.

To my mind, these two are mutually exclusive, if a teacher is going to concentrate on what causes proficiency.

Methods: specific procedures or sets of steps or activities that a teacher uses to teach language, based on the Philosophy he believes in (well, that SHOULD be obvious, because the activities that would be involved in (1) and (2) above are going to be really different from one another).

It might well be a good thing to identify distinct Methods within the Philosophy of CI teaching, because this would put paid to the accusations that “TPRS teachers think it is a silver bullet” and similar. The Rules-and-Output teachers typically say that they use “a variety of methods”, but all of those methods conform to their basic Philosophy. In fact, they DO NOT use methods from the CI philosophy in that any input they provide is not typically made 100% comprehensible. They do provide input, and many use that as “evidence” that they “also” use methods from the CI Philosophy of teaching (which they are not, if the input is not truly comprehensible).

TPRS is one Method within the CI Philosophy.
Krashen’s new ideas about Extensive Free Voluntary Reading could be another if they are picked up and operationalized in the classroom. (I have more thoughts on this but this is not the place for them).