Stipulating universal propositions with a ceteris paribus clause is common in science, especially in economics. However, there are issues with using these clauses in theories and policies. Ceteris paribus clauses are meant to isolate variables, but if not specified well, they can include variables instead. In such cases, theoretical abstraction may be more appropriate. However, abstract theories can lead away from real-world details needed for policy-making. To address this, interdisciplinary approaches in concept selection are advocated.