Most scholars engaged in ideational analysis agree that the availability of new ideas may cause existing welfare state policies and institutions to alter. This article considers the extent to which the open functional approach and constructivist approaches are able to explain the role of ideas in policy and institutional change. Notwithstanding their contribution to the study of the role of ideas in policy and institutional change, these approaches suffer from some shortcomings as they fail to view ideas as non-stable entities. In order to address these shortcomings, an alternative poststructuralist discourse theoretical explanatory model is presented. Applying this model to the case of the rise and fall of Dutch life course policy, the article shows how a discourse theoretical view of ideas as flfoating signifiers contributes to the study of the role of ideas in welfare state change.