The U.S. Court of Appeals for the Federal Circuit in recent years has embraced the use of bright-line formalistic rules in the interest of increasing certainty in patent law. This formalistic approach pervades the court's jurisprudence and extends far beyond claim construction. The Supreme Court has also expressed an interest in certainty in patent law, but its approach has varied from that of the Federal Circuit. Whereas the Federal Circuit has articulated bright-line substantive rules that are outcome determinative, the Supreme Court has articulated process-based formalistic rules, such as the use of rebuttable presumptions, which do not preordain a certain outcome and thus provide greater fairness. This article reviews the Supreme Court's patent-related jurisprudence to explore the differences between the Court's and the Federal Circuit's views on certainty. Next, the article evaluates the Federal Circuit's claim construction jurisprudence and assesses which doctrines and methodologies, if any, are consistent with the Supreme Court's view. Finally, the article concludes that the Federal Circuit should embrace claim construction methodologies that are more akin to rebuttable presumptions instead of the estoppel-like approaches it presently uses. While such a change may sacrifice some certainty, it would better comport with Supreme Court precedent and afford greater fairness to patentees.