Linguists and philosophers commonly distinguish between semantics and pragmatics, where the former concerns the truth or falsity of linguistic items and the latter concerns aspects of the use of such items that may make them unassertable even when true. Common though the distinction is, there is an ongoing controversy about where exactly the line between semantics and pragmatics is to drawn. We report two experiments meant to investigate empirically whether there is any pre-theoretic distinction that might help settle the debate. The same experiments are meant to shed light on a related question, namely, whether pragmatic aspects of language use pertain only at the level of assertability and not at that of believability. Our results suggest that ordinary people do not reliably distinguish among truth, assertability, or believability. We argue that this has consequences for the methodology of experimental semantics and pragmatics.