This article argues that cross-disciplinary linkages -- that is, relationships among phenomena studied by those in different disciplines -- often serve to destabilize, at least temporarily, systems of stability that are theorized to operate within the sets of phenomena studied within most disciplines. It surveys across disciplines both systems of stability and mechanisms of instability, and derives several implications for interdisciplinary and disciplinary research practice. In particular it argues that systems of stability deserve to be included within conceptions of disciplinary perspective. It speculates on how a general connection between stability and instability might be explored. The article thus informs our understanding both of what interdisciplinarity is and how it is best performed.