In intersystemic cases, a court applies the law of a foreign system. Scholars have argued that the court ought to use the interpretive methodology of the foreign system’s courts. I argue against that intuitive position. First, interpretive methodology is not bound up with primary rights and duties such that it constitutes substantive law for conflict of laws purposes. Second, although interpretive methodology has epistemic value and may affect case outcomes, a given methodology might not have the same epistemic value or the same effect on outcomes for differently situated interpreters. Further, the approach that the foreign judges take to interpreting their own law is necessarily anchored to the foreign system’s rule of recognition, which is not true of the approach of external judges. Descriptive facts might align such that external interpreters would have to use the internal methodology to identify the applicable law, but that’s an empirical question the answer to which will vary from case to case.