In copyright law, the useful articles doctrine plays a significant role in defining the limits of copyright’s domain and the boundary between copyright and patent. But the implicated notion of “conceptual separability” has proved to be difficult to define, and the Supreme Court’s effort to define it in the recent case Star Athletica, L.L.C. v. Varsity Brands, Inc. is unsatisfying. In an effort to resolve this challenge, the present paper puts forth a novel test for conceptual separability, one that draws inspiration from the philosopher’s idea of conceivability. The test is the following question: “When you conceive of the relevant useful article as lacking the design element in question, is the article you imagine functionally identical to the actual article?” If the answer to this question is yes, then the design element is conceptually separable from the article’s utilitarian aspects; if not, then the element has failed the test, and it is not entitled to copyright protection. The present paper explores why this novel proposal avoids many of the pitfalls of existing tests (including the Court’s own in Star Athletica), why it best achieves the aims of the useful articles doctrine, and what questions remain once the challenge of conceptual separability has been resolved.