There is room to debate what makes an invention patentable, but one thing should be uncontroversial: patentable inventions should actually be new. That’s what EFF and the R Street Institute told the Supreme Court this week in an amicus brief urging it to grant certiorari and reverse the Federal Circuit’s decision in Ariosa v. Illumina [PDF]. We explained that the Federal Circuit’s decision is wrong on the law and bad for innovation, access to knowledge, and the patent system.

In Ariosa, the Federal Circuit departed from more than a century of case law to uphold a patent that claimed an “invention” that someone else had already described in a published patent application. According to the court, the description didn’t qualify as material that could invalidate the patent being challenged because it did not appear in the “claims”—the section specifying the legal boundaries of the applicant’s rights – but rather in the section of the patent application describing the nature and operation of the applicant’s work.

This hair-splitting exception flies in the face of the Patent Act, which treats published patent applications just like granted patents in that they can invalidate later-filed patents based on all they describe, not just what they claim, based on the earliest filing date associated with the application. The Supreme Court has twice held that that rule applies to granted patents, but has not yet had a chance to confirm that the same rule applies to published patent applications.

EFF and R Street’s brief emphasizes the need for the Supreme Court to confirm what should be uncontroversial: to be patentable, inventions must be new. That follows from the Constitution’s mandate that the patent system promote innovation and technological progress. It is also consistent with the words of the Patent Act and the statements that Congress made when writing those words into law.

It also makes sense: Patents claiming advances made by others deplete from, rather than contribute to, the stock of public knowledge. The teachings of the earlier patent would be free for the public to use if not for the second-comer’s efforts at the Patent Office. Given the volume of patent applications and the resulting backlog at the Patent Office, the longstanding rule against such patents makes more sense now than ever.

By swinging open the Patent Office’s door to patents on old ideas, Ariosa’s approach cuts against the pro-innovation goal the Constitution sets forth for the patent system. We hope the Supreme Court will grant certiorari to confirm that the Patent Office must say no to second-comers seeking to patent the achievements of others.