Several prominent philosophers have held that physical properties are dispositions. The aim of this paper is to establish the following conjunction: if the thesis that physical properties are dispositions is unsupplemented by controversial assumptions about dispositions, it entails a contradiction; and if it is so supplemented the resulting theory has the consequence that either many worlds which seem to be possible worlds are not possible worlds or some properties which seem to be identical are not identical. In this way it (...) is shown that a dispositional account of physical properties is implausible. (shrink)