See my comment here. Thinking of laws as rules vs. descriptions may not predict different observations, but they do lead to different cognitive attitudes about scientific inquiry and explanation (e.g. we often think of rules as explaining behavior, but we don't think of descriptions as explanatory in the same way), and in this regard I think the prescriptive perspective is a recipe for confusion. One could say the same thing about the kind of empiricism advocated on LW as opposed to rationalism (of the traditional philosophical variety, not the LW variety). These two philosophical stances don't predict different observations, but that doesn't mean the choice between them is merely a linguistic one. They are associated with different pragmatic attitudes, and the empiricist attitude is a lot more valuable that the rationalist one.