Louis Goossens investigates the conceptual shift of the English modal 'must' from a deontic to an epistemic meaning. This general shift, which also applies to other modal verbs, has been accounted for in two different ways: as a metaphorical mapping from the sociophysical world onto the epistemic world (Sweetser 1990), or, especially in grammaticalization studies, as a shift triggered by context-induced inference. Both synchronic and diachronic data on the usages of ' must' suggest that the shift from deontic to epistemic is a gradual process, which can be accounted for by metonymic bridges. (Klaus-Uwe Panther and Günter Radden)