This investigation deals with modal verbs like 'können', 'müssen' and so on. When used in sentences like (1) 'Der Stuhl kann zusammenbrechen' or (2) 'Das musste ja so kommen' it is difficult to decide whether the modal verbs are used inferentially or non-inferentially. It is argued that in order to answer this question a hearer refers to the context and his knowledge concerning the discourse.