730
Opinion of the Court
lents. 234 F. 3d 558 (2000). The court held, with only one judge dissenting, that estoppel arises from any amendment that narrows a claim to comply with the Patent Act, not only from amendments made to avoid prior art. Id., at 566. More controversial in the Court of Appeals was its further holding: When estoppel applies, it stands as a complete bar against any claim of equivalence for the element that was amended. Id., at 574-575. The court acknowledged that its own prior case law did not go so far. Previous decisions had held that prosecution history estoppel constituted a flexible bar, foreclosing some, but not all, claims of equivalence, depending on the purpose of the amendment and the alterations in the text. The court concluded, however, that its precedents applying the flexible-bar rule should be overruled because this case-by-case approach has proved unworkable. In the court's view a complete-bar rule, under which estoppel bars all claims of equivalence to the narrowed element, would promote certainty in the determination of infringement cases.
Four judges dissented from the decision to adopt a complete bar. Id., at 562. In four separate opinions, the dissenters argued that the majority's decision to overrule precedent was contrary to Warner-Jenkinson and would unsettle the expectations of many existing patentees. Judge Michel, in his dissent, described in detail how the complete bar required the Court of Appeals to disregard 8 older decisions of this Court, as well as more than 50 of its own cases. 234 F. 3d, at 601-616.
We granted certiorari. 533 U. S. 915 (2001).
II
The patent laws "promote the Progress of Science and useful Arts" by rewarding innovation with a temporary monopoly. U. S. Const., Art. I, § 8, cl. 8. The monopoly is a property right; and like any property right, its boundaries should be clear. This clarity is essential to promote progress, be-
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