Abstract: The fair use doctrine requires courts “to avoid rigid application of the copyright statute when, on occasion, it would stifle the very creativity which that law is designed to foster.” Campbell v. Acuff–Rose Music, Inc., 510 U.S. 569, 577 (1994). The Federal Circuit’s rejection of a jury finding of fair use instead embraced a rigid approach that, as a matter of law, would bar any copying of code into a new program, even for a different platform, as non-transformative and unfair. To justify its ruling, the Federal Circuit abandoned a consensus in the lower courts about the broad scope of fair use when dealing with highly functional software elements. It made key mistakes about the fair use factors and their balancing, including inflating the relevance of commerciality, applying an erroneous “no more than necessary” standard for copying, dismissing as insignificant the highly functional nature of computer programs, and conflating the market for Java SE as a whole with the market for individual declarations. Absent these legal errors, it is clear that the jury was at least reasonable in making factual findings that supported a finding of fair use. The extent to which a new work has a new meaning, message, or purpose—transformativeness—is often and rightly prioritized in the fair use analysis. But what constitutes transformativeness is often contentious. Here, the new purpose of Google’s new code implementing the declarations was the creation of a new computing environment in which Java programmers could readily create programs on multiple platforms, which required the use of limited portions of highly functional declarations. This type of purpose has been recognized as transformative because of its role in furthering competition and innovation. A computer interface supports the creation of other creative works, and in such situations, it is important to avoid locking in third parties to specific platforms. Factors two and three of the fair use test help define the boundaries of this type of fair use. In cases such as the one at bar, the highly functional nature of the copied declarations and the limited amount of the overall Java SE work used, consistent with industry practices, are vital considerations supporting the conclusion that Google’s use was a transformative use that served copyright’s basic goal of encouraging creation of new works. By discounting to the point of irrelevance the thinness of protection for highly functional aspects of computer interfaces (factor two) and of the industry practice of treating the amount Google reimplemented as reasonable (factor three), the Federal Circuit distorted its analysis of the other fair use factors, threatening the coherence of fair use doctrine and the ultimate progress of creativity. By downplaying the relevance of the nature of the work and the amount taken, the Federal Circuit fell into the well-known trap of circularity: reasoning that, because Oracle could have charged a license fee for this type of use if fair use were unavailable, Oracle suffered cognizable market harm. Because such claims can be made for any fair use, which by definition is not paid for, this reasoning cannot distinguish fair and unfair uses. But factors two and three can help identify when crediting such claimed market harm would be inconsistent with copyright’s overall balance between past and future creators. Thus, given the limited copying of functional elements here, factors one and four also support fair use, because Google’s purpose was generative of additional creativity by third parties and because Oracle’s claimed market harm goes beyond the legitimate scope of its thin copyright in highly functional declarations. A thin copyright for software, including Java SE, provides software copyright owners with meaningful protection against copying of significant amounts of expression, but meaningful protection does not require the expansive rights that the Federal Circuit granted. Providing a broad scope to highly functional elements of software is unnecessary and dangerous to competition and innovation. Factors two and three enable fair use to implement this distinction between types of works. The Federal Circuit erred in not recognizing this interaction between the fair use factors and instead adopting a rigid rule that would preclude fair use in computer programs.