Argumentation in everyday life is a matter of pragmatics. A speaker who utters an assertion that is meant to be an argument is not only committed to the truth of the assertion itself and its presuppositions but also to the implicit premises that make the assertion a reasonable argument. For example, if a speaker utters an argumentum ad verecundiam “Dr XY said so”, he is committed to the truth of “Dr XY is an expert in the relevant field” among other premises. This follows from the properties of assertions alone if the commitment attributed to assertions is extended from ‘commitment to truth’ to ‘commitment to relevance’.