In this note I test a specific thesis about the dependence of philosophy of science on science that Laudan presents in his Science and Hypothesis; namely, that the sciences were justificationally prior to the philosophy of science. I argue that Laudan's historical case studies show a justificational priority that goes the other way. I also argue that the justificational role that in Progress and Its Problems the history of science is alleged to play vis-à-vis competing conceptions of scientific rationality is not apparent in Laudan's argumentation in favor of his suggested analysis in terms of problem-solving effectiveness.