The rule concerning irrelevant propositions is generally accepted by all medieval authors writing on obligations, but in importantly different exact versions. We will come back to some of these versions in the following, but first we must make clear about Burley’s version. He puts special attention to the following question: a proposition is relevant if it follows or is incompatible, but follows from exactly what, or is incompatible with exactly what? As Burley sees it, this relevance must be de