Our topic is the ontology and persistence conditions of material objects. One widely held doctrine is that identity-over-time has causal commitments. Another is that identity-over-time is just identity (simpliciter) as it relates one object that exists at two times. We believe that a tension exists between these two apparently sensible positions: very roughly, if identity is the primary conceptual component of identity-over-time and—as is plausible—identity is noncausal, then the conceptual origins of the causal commitments of identity-over-time become a mystery. We will begin by formulating the two widely held doctrines and our puzzle more fully and more carefully. Then, the remainder of the paper will be devoted to analyzing views one might adopt that could minimize the tension.