I recently read the following argument on a blog, and I was wondering what the panelists might say about it. It is a well known philosophical principle that one cannot infer normative facts from empirical ones (this is the is-ought problem). But if, as it is often supposed, "ought implies can," then cannot implies ought not ("ought not" in the sense of "not obligatory"). In that case, we can infer normative facts from facts about empirical facts about what people cannot do.