Yet there are many ways of organizing phenomena besides revealing mechanisms. Some scientists are concerned with physical structures and their spatial relations without regard to how they work: an anatomist might be interested in the spatial organization of parts within the body with minimal interest in how those parts articulate together to do something. Many scientists build predictive models of systems without any pretense that these models in fact reveal the causal structures by which the systems work. Some scientists are concerned with taxonomy, sorting like with like without regard to how the sorted items came about or how they work. Finally, in many areas of science, there is a widely recognized and practically significant distinction between knowing that C (e.g., smoking) is a cause of E (lung cancer) and knowing how C causes E. This is not so much an ontological difference as it is a difference in the grain with which one seeks to understand a system’s causal structure. In short, there are many framework concepts in science, and not all of them can be assimilated to mechanisms.