Nautilus v. Biosig - What Will Be The New Test For "Reasonable Certainty"?
Saturday, June 7, 2014 at 10:04 AM
Justin E. Gray in Federal Circuit, Supreme Court

Nautilus, Inc. v. Biosig Instrucments, Inc. (U.S. Supreme Court June 2, 2014)

As has been written about at length, the Supreme Court has rejected the "insolubly ambiguous" test finding it "does not satisfy" 35 U.S.C. 112 P2 and has instead held that "a patent is invalid for indefiniteness if its claims, read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of invention."  The Court explained that "[t]o tolerate imprecision just short of that render­ing a claim 'insolubly ambiguous' would diminish the definiteness requirement’s public-notice function and foster the innovation-discouraging 'zone of uncertainty,' United Carbon, 317 U. S., at 236, against which this Court has warned."

It will be interesting to see what the Federal Circuit does on remand with the Supreme Court's new standard.  Will the Federal Circuit create a new test to help both itself and lower courts determine what does and does not inform those skilled in the art with "reasonable certainty"?  Perhaps the Federal Circuit will try to formulate a test that expressly includes the idea from Exxon (with its roots in Athletic Alternatives) that "no narrowing construction can be adopted" (an idea that did not appear in the Federal Circuit's Nautilus opinion) and was explained further in a recent Federal Circuit case decided after cert was granted in Nautilus, namely Takeda v. Zydus.  While Exxon (and the "no narrowing construction" language) was cited by the Supreme Court in a footnote as an example of Federal Circuit decisions using the now-defunct "insolubly ambiguous" language, the likelihood that the Supreme Court will take another 112 P2 case in the foreseeable future is small.  Thus, what the Federal Circuit does with the Nautilus remand has the potential to be the new indefiniteness test for quite some time. 

If readers have thoughts on what the Federal Circuit may do with the Nautilus remand, I would appreciate hearing them.  Feel free to email me at

Article originally appeared on A Claim Construction and Patent Law Blog (
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