Neither software nor computer programs are explicitly mentioned in statutory United States patent law. Patent law has changed to address new technologies, and decisions of the United States Supreme Court and United States Court of Appeals for the Federal Circuit (CAFC) beginning in the latter part of the 20th century have sought to clarify the boundary between patent-eligible and patent-ineligible subject matter for a number of new technologies including computers and software. The first computer software case in the Supreme Court was Gottschalk v. Benson in 1972. Since then, the Supreme Court has decided about a half dozen cases touching on the patent eligibility of software-related inventions. The eligibility of software, as such, for patent protection has been only scantily addressed in the courts or in legislation. In fact, in the recent Supreme Court decision in Alice v. CLS Bank, the Court painstakingly avoided the issue, and one Justice in the oral argument repeatedly insisted that it was unnecessary to reach the issue. The expression "software patent" itself has not been clearly defined. The United States Patent and Trademark Office (USPTO) has permitted patents to be issued on nothing more than a series of software computer instructions, but the latest Federal Circuit decision on the subject invalidated such a patent. The court held that software instructions as such were too intangible to fit within any of the statutory categories such as machines or articles of manufacture. On June 19, 2014 the United States Supreme Court ruled in Alice Corp. v. CLS Bank International that "merely requiring generic computer implementation fails to transform [an] abstract idea into a patent-eligible invention." The ruling continued: [...] the mere recitation of a generic computer cannot transform a patent-ineligible abstract idea into a patent-eligible invention. Stating an abstract idea "while adding the words 'apply it'" is not enough for patent eligibility.[] Nor is limiting the use of an abstract idea "'to a particular technological environment.'"[]. Stating an abstract idea while adding the words "apply it with a computer" simply combines those two steps, with the same deficient result. Thus, if a patent's recitation of a computer amounts to a mere instruction to "implemen[t]" an abstract idea "on . . . a computer," [] that addition cannot impart patent eligibility. Law Constitution Article 1, section 8 of the United States Constitution establishes that the purpose of intellectual property is to serve a broader societal good, the