Breyer J. --"But where a statute leaves a “gap” or is “ambigu[ous],” we typically interpret it as granting the agency leeway to enact rules that are reasonable in light of the text, nature, and purpose [**] of the statute. Mead Corp., 533 U. S., at 229; Chevron U. S. A. Inc., supra, at 843. The [IPR] statute contains such a gap: No statutory provision unambiguously directs the agency [(the USPTO)]to use one standard or the other. And the statute “express[ly] ... authoriz[es] [the Patent Office] to engage in the process of rulemaking” to address that gap."
** Article I, Section 8, Clause 8 --To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries.
Sotomayor J. sorry for meth dealer but not inventors? (here)