Since about 2003, the notion of threshold concepts--the central ideas in any field that change how learners think about other ideas--have become difficult to escape at library conferences and in general information literacy discourse. Their visibility will likely only increase because threshold concepts figure prominently in the Framework for Information Literacy for Higher Education, still under development by the Association of College and Research Libraries (ACRL). Nevertheless, few scholars have critically considered the wider intellectual ramifications of certain assumptions fundamental to threshold concepts in library and information literacy instruction. This paper is an initial attempt to promote such discussions.